Пориста структура порошків нанорозмірного боразографену
The structural features of surface of the nano-dimensional bor-azo-graphenic powders (t-BNg) after previous washing in boiling water were researched. The results showed that after process of purifier (washing) the powder’s surface of t-BNg characterized as slit-like micro-, mesoporous (monodispersed...
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Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2017
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| author | Petrova, A. V. Garbuz, V. V. Lobunets, T. F. Tomila, T. V. |
| author_facet | Petrova, A. V. Garbuz, V. V. Lobunets, T. F. Tomila, T. V. |
| author_institution_txt_mv | [
{
"author": "A. V. Petrova",
"institution": "Інститут проблем матеріалознавства ім. І. М. Францевича НАН України"
},
{
"author": "V. V. Garbuz",
"institution": "Інститут проблем матеріалознавства ім. І. М. Францевича НАН України"
},
{
"author": "T. F. Lobunets",
"institution": "Інститут проблем матеріалознавства ім. І. М. Францевича НАН України"
},
{
"author": "T. V. Tomila",
"institution": "Інститут проблем матеріалознавства ім. І. М. Францевича НАН України"
}
] |
| author_sort | Petrova, A. V. |
| baseUrl_str | |
| collection | OJS |
| datestamp_date | 2018-12-01T11:25:21Z |
| description | The structural features of surface of the nano-dimensional bor-azo-graphenic powders (t-BNg) after previous washing in boiling water were researched. The results showed that after process of purifier (washing) the powder’s surface of t-BNg characterized as slit-like micro-, mesoporous (monodispersed) structure with a narrow porous distribution in the range of 3.82 - 4.17 nm. The outer surface specific area of the powders of t-BNg according to “t - method” is 28.3 m2/g. The inner specific surface area of the mesopores is 141 m2/g (BJH method). The residues of boron oxonitride in the form of a purified sublimate, a white powder, extracted from a washed and dried sample of t-BNg at a temperature of 540 K and a pressure of ≤ 1.0 Pa. The sublimate, according to chemical analysis and infrared spectroscopy, was identified on the assumption of the cyclic dimer of di-hydro-di-hydroxo-di-bor-ox-azole of the composition of H(OH)[(BON)2](OH)H. The model of carbamide synthesis of boron nitride, as a sequence of chemical transformations of borate-carbamide precursors in a freely radical boron-pair (> B - N <), have proposed. |
| doi_str_mv | 10.15407/Surface.2017.09.081 |
| first_indexed | 2025-07-22T19:34:43Z |
| format | Article |
| fulltext |
Поверхность. 2017. Вып. 9(24). С.81–95 81
ФИЗИКО-ХИМИЯ ПОВЕРХНОСТНЫХ ЯВЛЕНИЙ
UDC 541.1 + 620.22 + 546.171.1 / 27 + 620.18
POROUS STRUCTURE OF NANO-DIMENSIONAL BORASO-
GRAPHENIC POWDERS
A.V. Petrova, V. V. Garbuz, T.F. Lobunets, T.V. Tomila
Institute for Problems of Materials Science. I. Frantsevich National Academy of Sciences of Ukraine,
Krzhizhanovsky str., 3 Kyiv, 03680, Ukraine, e-mail: wpetrowa@ukr.net; Garbuz.v1950@Gmail.com
The structural features of surface of the nano-dimensional bor-azo-graphenic powders (t-BNg)
after previous washing in boiling water were researched. The results showed that after process of
purifier (washing) the powder’s surface of t-BNg characterized as slit-like micro-, mesoporous
(monodispersed) structure with a narrow porous distribution in the range of 3.82 - 4.17 nm. The outer
surface specific area of the powders of t-BNg according to “t - method” is 28.3 m2/g. The inner specific
surface area of the mesopores is 141 m2/g (BJH method). The residues of boron oxonitride in the form of
a purified sublimate, a white powder, extracted from a washed and dried sample of t-BNg at a
temperature of 540 K and a pressure of ≤ 1.0 Pa. The sublimate, according to chemical analysis and
infrared spectroscopy, was identified on the assumption of the cyclic dimer of di-hydro-di-hydroxo-di-
bor-ox-azole of the composition of H(OH)[(BON)2](OH)H. The model of carbamide synthesis of boron
nitride, as a sequence of chemical transformations of borate-carbamide precursors in a freely radical
boron-pair (> B - N <), have proposed.
Key words: surface structure, borazographene, impurity, boroxazole, dissolution
Introduction
Natural mineral, millimeter crystals of cubic c-BNs was named as qingsongite [1]. All
other modifications of boron nitride have considered as synthetic. In practice, graphene-like,
(disordered, turbostratic) boron nitride (t-BNg) [2 – 4] is a raw material for the production of all
nanoscale powders of layered and dense modifications. Graphite-like h-BNg is forming at
temperatures up to 1773K [5 – 7]. Wurtzite-like h-BNw and sphalerite-like c-BNs prepared by
method of compression in shock wave (CSW) of h-BNg and t-BNg powders [7 – 9],
respectively. The layered modifications of BN in the conditions of static and gradient heating
at area 2003 - 3503 K and a pressure of 5 - 18 GPa leads to the aggregation of powders of h-
BNw and c-BNs [10 – 12]. T-BNg is a space isomer of graphene. Varieties of boron nitride
derivatives are the most similar to modifications and forms of carbon [13]. BN may to form
nanofibers [14], nanotubes [15, 16], nano-films of dense modifications [17], and carbo-bor-azo
hetero diamond [18]. Non-oxygen samples of t-BNg, as well as graphene-like layers on metals
in nanosized semiconductor elementary devices, have obtained by thermal decomposition of
toxic element-organic borohydrides or boron-chlorides with metal calcium [19, 20, 21 – 26].
Micro-dimensional powders produced from borazohydrides have used for X-rays characteristics
of powders of Graphene-like t-BNg as the standard. It have two X-rays reflections only. The
first of its d002 equal 0.3430 nm. Second plane reflection of d10 - 0.2503 nm [7, 19, and 20]. It is
meaning that structure of t-BNg have physical two-dimensionality. Graphene-like 2D boron
nitride become to graphite-like 3D modification at heating from 1270K to 1470K and up to
1773 K. Its structure differs from the graphite-like 3D modification by other laws of extinction
of X-ray reflections. Crystallographic space group from P63 is ordering in to P63/mmc [7].
82
Well-known ordering can to be observe in case of phase transition from fluorite structure to
phyrochlore, from space group Fm3m to Fd3m.
As a rule, graphenic-like boron nitride is produced massively from borate acid H3BO3 or
B2O3 in acid-base interaction with carbamide (NH2)2CO in NH3 or N2 (H2) atmosphere at
temperatures of 1173 K and above 1273 K [27]. However, this way of synthesis a more amount
of experimental information still needs have properly explained out. The problem is that t-BNg
carbamide synthesis powders differ in their composition. The ratio of the main components is
not stohiometric (B / N ≠ 1). The abnormal excess of oxygen (WO >> 1 – 10 %, by mass). The
middle size of the plane (macromolecules) nanoparticles (in Coherent Scattering Area of 2D
hk10 reflections have 1 – 3 ... 30 – 50 nm). Values of structurally interlayer parameters have d002
= 0.342 – 0.358 nm [28]. The issues of cleaning and studying impurities in t-BNg are still
relevant. The study of the surface structure in case of the pure powders of graphenic-like boron
nitride has practically not carried out. That would be so interesting.
In recent years, the perfect porous sorbents of BN by using of other nitrogen-containing
substances with more alkaline properties were obtained. Structural units of material are
considered of nano plates or sheets with a thickness of not more than three graphene-like layers
[29]. The material has a branched slit-like and spherical multifunctional, meso- and macro
pores surface, which provides a high dynamics of sorption-desorption processes.
Experimentally established sorption relation of the mass of the oil hydrophobic type pollutions
to conditional mass of the sorbent is from 30/1, next 17/1 in five cycles after cleaning by
burning at 870 K. Hydrophilic soluble dyes and heavy metals of electrolytic origin were up to
relation of 0.5/1. Master's programs for training specialists in area of promising to use of porous
BN as mobile hydrogen storage material have been developed [30]. The main advantage of the
BN-based sorbents is its ability to recycle and reuse multiple times, which gives a significant
advantage over another ones.
In connection with the foregoing, the surface structure of sorption materials based on
graphene-like boron nitride is complex. Therefore, the investigation of the gap (slit) component
of the surface structure of these materials is of some interest. The purpose of this work was to
study the dimensional, volume and planar characteristics of the slot pores of nano sized
powders of graphene-like boron nitride.
Certifications of the porous structure of the batch of t-BNg powder obtained by the
carbamide synthesis method in the IPM of the National Academy of Sciences of Ukraine have
carried out. Incoming control, powder washing, and the nature of the impurity have established.
Experiment
To attest the samples, a complex of chemical and physical-chemical methods of integral
elements chemical analysis have used [27]. Samples were pre-washed in ethanol to dissolve
possible impurities of boric acid or boron oxide, as in [48]. Part of the sample has treated with
boiling water for one hour in a conical flask with a reverse water cooler. The residue have
filtered off, washed and dried at a temperature of 400 K to constant weight. The content of total
carbon in the solid phase decreased from 0.5 to 0.3% (by mass), hydrogen - increased from 0.2
to 0.9 % (by mass), respectively.
Investigation of the porous structure of the samples was carried out using an ASAP
2000M (Accelerated Surface Area and Porosimetry System), designed to obtain isotherms of
adsorption of gases (nitrogen, argon, krypton, and other non-aggressive gases) by help with of
adsorption-structural static volume method. The measurement range of this method is in the
range of pore sizes from 0.3 to 300 nm. In these studies, as the adsorbed gas was used nitrogen.
According to the recommendations of IUPAC [32], the classification of pores is limited in size.
The super micropores have x < 0.6 – 0.7 nm; micropores 0.6 – 0.7 < x < 1.5 – 1.6 nm;
mesopores 1.5 – 1.6 < x < 100 – 200 nm and macro pores x > 100 – 200 nm. Characteristic or
83
effective pore sizes are determined in the direction of normal to the movement of molecules
when they are filling. The characteristic size of the cylindrical pore is its radius, and the slit
pore is the half-width of the crack. Each pore interval corresponds to certain adsorption
properties. In micropores, adsorption occurs according to the mechanism of volume filling. In
mesopores, by capillary condensation, where on isotherms a characteristic loop of hysteresis
was observed. It is impossible to study the isotherm of macro-pores adsorption because of its
proximity to the direct P/P0 = 1, where P is the adsorption pressure and P0 is the pressure of the
saturated adsorption vapors. The boundaries between different classes of pores have not
precisely defined, since it also depends on their form. The basis of the method lies in the ability
of solids to absorb gases and vapors. Quantitatively, this ability have depicted in the form of a
dependence of the volume of gas absorbed by the sample, on the partial or relative pressure of
this gas at a constant temperature. That is, in the form of isotherms of adsorption - desorption.
Isotherms and hysteresis loops have interpreted by types [31, 32]. It were calculated total pore
volume (Vsum, cm3/g) and specific surface by the method of BET (SBET, m2/g) [33 – 35]. The
total volume (Vmeso, cm3/g) and the surface (Smeso, cm2/g) of mesopores. Differential
distributions porous volume and surfaces area were calculated according to BJH theory [36,
37]. Average equivalent diameter of the pores, were calculated according to the theory of BET
and BJH (Daverage). Volume, surface area and the distribution of the micropores in size
according to the theory of Horwath-Kawazoe (HK) [38 39, 40].
The method of X-rays have used for determine the phase composition of t-BNg powders
with using of DRON-2,0 diffractometer, Cu-Kα laser radiation with ASTM library. The intensity
of the lines have calculated on a 100-point scale. The values of the interplanar distances d, (Е)
were computed from the equation:
2d = λ/sin θ, (1)
where are: – interplanar distance; λ – the wavelength equal to 0,154178nm; θ – angle of
reflection.
Transmission microscopy (PEM) studies were performed with help of JEM-100 CX and
JEM-2100F instruments.
The structural features of the samples have studied using the IR spectroscopy
(computerized complex based on Specord M80) in the region 4000 – 400 cm-1. The test samples
have thoroughly mixed with KBr powder in a ratio (1:300) mg. The resulting mixture
compressed into clear tablets (rectangular plates in the size of ~ 5.26 mm2.
Results and discussion
The results of X-ray diffraction investigations and element chemical analysis of samples
BN indicate about of the character of nature of impurities. The presence of whose affects the
value of d002 in this disordered (mesomorphs), isostructural phases of t-BNg, (Table 1).
Investigation of the porous structure
The measuring range of this method was in the range of equivalent pore sizes from 0.3 to
300 nm. The nitrogen have used as the adsorbed gas. Vacuum heat treatment (degassing) the
samples of the initial and washed t-BNg at a temperature of 400 K and 540 K for making
isotherms of nitrogen sorption were subjected. The obtained porosity characteristics have
presented in the table 2 and in Fig. 2.
84
Table 1. Results of elemental chemical analyses and X-ray diffraction characteristics of t-BNg
powders [28].
Elemental account of boron,
nitrogen and oxygen in
samples
Interplanar
distance
Average
diameter
рarticle,
RKR hk10
Name
Sample
t‐BNg
wВ±0,1 %,
mass
wN±0,1 %,
mass
wO±0,1 %,
mass
d002, nm da, nm
I 41,2 50,1 7,1 0,358 4 – 5
II 35,2 45,6 18,7 0,342 1 – 3
Fig. 1. X-ray diffraction of t-BNg: І – initial sample; t-BNg; ІІ – washed t-BNg [28].
Table 2. Basic porosity characteristics of samples
t‐method BJH
N
am
e
Sa
m
p
le
te
m
p
e
ra
tu
re
, K
V sum,
сm3/g
S BET,
m2/g
Vmicro,
сm3/g
Sinner
micro,
m2/g
S
external,
micro,
m2/g
Vmeso‐,
сm3/g
S meso‐,
m2/g.
D average,
nm
1 I 400 0,1329 79,2 0,0196 45,34 33,81 0,1313 76,35 6,9
2 I 540 0,1943 137,2 0,0446 100,03 37,13 0,1900 112,66 6,8
3 II 400 0,1196 93,9 0,0408 67,12 26,92 0,1188 105,04 4,5
4 II 540 0,2039 257,5 0,1168 229,19 28,26 0,1535 141,6 4,3
Investigations have showed that the nitrogen adsorption isotherms of the samples refer to
the IV type of classification of isotherms, which characterizes them as bodies of mesopores
85
(Fig. 2). The hysteresis loops of the isotherms of the investigated samples belong to the type
H3. According to the classification of the hysteresis loop of isotherms, it has slit-like pores or
constructed of plane-parallel particles. At the same time, desorption ledge have observed on
branch of the obtained isotherms, which is characteristic for porous gaps of another structure.
The shape of the hysteresis loops of the isotherms obtained on the initial sample t-BNg (I)
is not clearly pronounced. In the sample material, in addition to the sliced pores, there are pores
near to cylindrical pores (Fig. 2). At the same time, two peaks have observed in the curves of
the differential distributions of the volumes and surface areas of the mesopores by size: a
narrow peak in the 3 – 4nm range, which was characterized by homogeneous monodisperse
bodies. Wider peaks in the range of 10 – 25 nm is typical for materials with aggregates of
similar sizes. An increase of the degassing temperature for the initial sample to 540 K leads to
an increasing of the sum characteristics of porosity. The degassing temperature is increasing of
the volume of micropores (less than 3 nm) and some variations in the differential distributions
of volume and surface area of the mesopores. The range of small pores expands, in due to at
low degassing temperatures the emptying of micropores and pores with dimensions of 3 - 4 nm
is partly due to the high potential of the surface. From the curves of the differential distributions
of pore volumes and pore surfaces area, it follows that the initial sample has a narrow
distribution in the range 3.82 – 4.17 nm (average pore diameter of 3.976 nm). Its number are for
about 36% of the volume and 60% of the mesopores surface area. The pore in range of 10 – 25
nm are wide distributed and accounted for about 34% of the mesopores volume. The specific
surface area calculated by the BET method has over estimated values. BET intended for
calculating the surface of homogeneous non-porous objects whose isotherms belong to the “I”
type of classification characterized for S-shaped curves. Thus, the initial powder can be
presented as a micro-mesoporous body with a capillary slit structure having an internal
aggregate (3.82 – 4.17 nm) and inter-aggregate (10 – 25 nm) porosity with a specific surface
area of 37 m2/g, according to the t-method, and area of the mesoporous surface have 112 m2/g.
Fig.2. Isotherms of nitrogen sorption on initial samples t-BNg.
86
Fig.3. Differential distributions of pore volumes and surfaces area according by size of the
initial t-BNg sample.
Washing of the initial sample (II) follow to some change of its porous structure. The
sorption isotherms on the washed sample t-BNg (II) not depend from the degassing temperature.
It characterize as a micro- mesopores material (Fig. 2). The hysteresis loop have become more
clearly for characteristic of the slit-like pore model. An increase in temperature when degassing
the treated sample to 540 K results to sublimating a white powder on the glass tube with the
sample, while the color of the own sample becomes slightly creamily. The differential
distributions of the mesopores volumes and surfaces are practically unchanged by size.
However, the sum characteristics of the porosity substantially increase. The average size of
mesopores remains the same. The number of micro- and mesopores increased. A significant
increase in the specific surface area of SBET is associated with the appearance of a significant
volume of micropores (up to 3 nm) and is clearly overestimated. The value of the surface area
calculated based on the t-method varies little. Increasing of degassing temperature promotes the
release of pores of fine dimensions. Thus, an increase in the degassing temperature of a washed
sample practically does not affect the porous structure of the samples, but contributes to a more
complete emptying of pores of fine dimensions. Differential distributions of volumes and
surfaces of mesopores by size at a degassing temperature of the sample of 540 K characterize it
is as a uniformly porous (monodisperse) with a narrow pore distribution in the range 3.35 –
4.12 nm (average diameter of 3.876 nm), which have about 55% volume and occupies to 60%
of the mesopores surface area. The range of pores over 24 nm prepare 12 – 15% of the
mesopores volume (Fig. 4).
Fig.4. Isotherms of nitrogen sorption on processed samples t-BNg.
87
Fig.5. Differential distributions of meso-pores volumes and surfaces in sizes on processed
samples t-BNg.
To compare the porous structure of the initial and washed BN samples, the nitrogen
sorption isotherms obtained at their degassing temperature of 540 K have used. The use of
washing helps to obtain a more uniformly porous structure for the powder. With an almost
identical total pore volume (pores with dimensions up to 300 nm), the volume of mesopores
decreases, but their area significantly increases, which is a consequence of a decrease in their
size. The average equivalent diameter of mesopores decreases. In addition, the volume of
micropores increases. The wider distribution of mesopores on the initial sample in the 3 – 4 nm
range narrows, the average mezzo-pore diameter of this range somewhat decreases - 3.876 nm.
In this case, the porosity in the range of 10 – 25 nm practically disappears. The initial sample is
converted into a mesoporous, predominantly monodisperse, slit-like structure, an essentially un
aggregated material with a narrow mezzo-pore distribution by size, with the average diameter
of this range decreasing from 3.976 nm (I) to 3.876 nm (II).
Thus, because of washing and vacuum-thermal treatment purification was obtained a
homogeneous, micro-mesoporous, monodisperse, (with a slit-like non-rigid structure and a
narrow distribution of slit-like pores in the range 3.53 – 4.12 nm), powder of graphene-like t-
BNg. The specific external surface area of the mesopores according to the t-method is ~ 28.3
m2/g. Specific inner surface area have 141.0 m2/g (BJH method). Since washing (purification)
of the source, material according to radiographic data leads to a decrease in the interplanar
distance d002 from 0.358 to 0.342 nm.
Average particle diameter have calculated in the coherent scattering (RKR) region of the
planar reflection hk10. According to electron diffraction data, the sizes particles from 4.0 – 5.0
nm for the initial powder decreases after washed to 1.0 - 3.0 nm. In addition, at cleaning the
particle size decreases. Sublimation of cyclic dimer of boron oxonitride occurs at WTT at
temperature of 540K. The poly-bor-oxonitride particles, probably, are localized in the indicated
pores.
88
Fig. 6. Isotherms of nitrogen sorption on t-BNg samples.
Fig.7. Differential distributions of micropores volumes by size
Fig.8. Differential distribution of volumes and pores surfaces by dimensions on samples t-BNg.
89
The IR spectrum data of the investigated initial sample “I” have characterized by
absorption bands of valence υ(BN) inner-planar and inter-planar vibrations in the region of ~
1392 cm-1 and 793 cm-1, respectively (Fig. 9 curve I) [28]. The arm in the frequency range ~
1330 - 1230 cm-1 refers to the valence asymmetric vibrations of υ (B-O-B) in the trigonal
coordination of boron [45]. The broad absorption band of the powder υ(1030 - 930) cm-1 and the
weak absorption band in the region of ~ 464 cm-1 related to valence and deformation vibrations
of υ(B-O-N) bonds [28, 46-48]. The absorption band with frequency of υ ~ 1100 cm-1 may be
assigned to the planar vibrations of υ (B-O-H) [48]. In the region of ~ 3,000 - 2800 cm-1, bands
characteristic of valence vibrations υ (CH) appear. Hydrogen-containing vibrations of NH and
OH groups are characterized by the presence of absorption bands of deformation vibrations of υ
δ(NH) -1550 cm-1, δ(OH) -1620 cm-1, and valence vibrations in the frequency range υ(NH) ~
3750-3300 cm-1, υ(OH) - 3430 - 3200 cm-1.
Fig. 9. IR-spectra of powders t-BNg [28]: I - starting powder; II - purified by boiling and WTT
sample t-BNg residue; IIa - sublimate.
Analysis of the IR spectrum of sample "II" t-BNg purified by the WTT (temperature
540 K) showed that the absorption bands in the region of υ ~ 1340 – 1100 cm-1, characteristic
for B-O-B and B-O-H vibrations disappeared (Fig. 9, curve II). The intensity of the absorption
bands characteristic of B-N, OH, and NH vibrations have increased with respect to the initial
sample t-BNg. The absorption bands characterizing the vibrations of the B-O-N bond are
present in the IR spectrum of the purified WTT sample of t-BNg. This indicates that the bond is
so strong. It is difficult completely remove oxygen by the WTT.
The IR spectrum of sublimated powder have shown in Fig. 9. Curve IIa have
characterized by wide diffuse absorption bands characteristic of a disordered amorphous
structure in the region of 1900 – 900 cm-1. Bands of absorption are characterized for vibrations
of B–O, B–O–H, B–O–B, BN, NH and OH. Analysis of the results of IR spectroscopy
suggested of powders produced by urea synthesis have provided. A complex with characteristic
vibrations of B–O, B–O–N, B–O–H, B–O–B, BN, and OH bonds have formed In addition to t-
BNg. It was assumed that poly-condensed compound in the form of flat particles t-BNg formed
as transition state of poly types from B2O3 to BN [46].
The sequence of chemical transformations in the carbamide synthesis of boron
nitride is complemented by the process of stabilizing the monomers H2N-B=O by its
cyclization. In due to the fact that the interaction of borate acid with urea is the reaction of acid
neutralization with the base - urea or ammonia. It is the evaluation of CO2 from the urea residue
and the multistage dehydration that ends with the formation of the final product of BN. Acid
properties of the borate component in the forms of Orto-, meta-borates or anhydride lead to a
series of successive reactions with the formation of the main product - nanosized particles of
turbostratic-boron nitride (2).
90
2O=B‐OH + (H2N)2=CO → ‐H2O; ‐CO2 → 2H2N‐B=O → ‐H2O → =B‐N= →
→ (BN)3 →(BN) 3n (2)
The presence of a certain number of dissociated molecules of meta-borate acid changes
the way of interaction with urea. Amino groups are exchanged with dissociated protons with the
formation of formaldehyde H2 > C = O and amine meta-borate O = B - O - NH2. The latter its
dimerized into cyclic di-hydro-di-hydroxo-boroxazole H(OH)[(BON)2](OH)H, whose
dehydration enables the formation of polymeric planar particles of analogies t-BNg, soluble in
water. The sequence of transformations have represented by the following schematic sketch (3):
Schematic sketch (3):
Dimeric sublimate, the remnant of the disintegration of boron oxonitride polymer, was
experimentally isolated with a vacuum for thermal purification of a turbostratic BN powder at a
temperature of 540 K and a pressure of ~ 1.0 Pa [12]. Proceeding from the proposed reactions
(2, 3), in the carbamide synthesis of boron nitride as model for the formation and stabilization
of boron oxonitride in the form of a structural scetch shown in the figure 10.
Fig. 10. Model of levels (I 1, 2 – II 3, 4
– III 5, 6) of hydrolysis of the
peripheral perimeter of boron
and nitrogen atoms of a
macromolecules of t-BNg.
Degree of polymerization, n -
0; 1; 2. The presence of these
vibrations in the IR spectra of
samples indicates the
coexistence of all these levels.
91
Segments:
I) the initial state 1 and 2 - the compensability of charges δ+ and δ - in peripheral atoms of
B3+ and N3- ;
II) 3 - joining of OH- groups to boron δ+and 4 - the addition of H+ to nitrogen δ -in the
interaction with water vapor in the air;
III) 5 - dehydration of neighbors OH- groups of boron and 6 - replacement of nitrogen N3-
with О2- - oxolation (occurrence of non-stoichiometric).
In the infrared spectra of real samples t-BNg, there are bands of II and III levels of
peripheral interaction with H2O.
1 and 2 - in the absence of atoms and groups of joining and substitution,
3 - Hydroxylation of boron,
4 - Hydrogenation of nitrogen in contact with water vapor.
5 - Dehydration of boron,
6 - Nitrogen thermo hydrolysis, occurrence of non-stoichiometric B/N ˂ 1.
The model indicates the presence of structural state features such as non-stoichiometric
and oxygen content. It have confirmed by the results of experimental studies using chemical
and chemical-phase analysis, IR spectroscopy, X-ray and electron transmission microscopy
(Fig. 11).
Fig. 11. Transmission electron microscopy of
the t-BNg [28].
Conclusion
The results of the work of recent years have formed a new scientific direction. Its purpose
is to obtain and certify new renewable sorbents. Local and large-scale cleaning of water
resources of the environment justifies the financial and intellectual costs for their creation.
Powders and porous ceramic materials based on graphene-like boron nitride (BN graph) with a
developed external and internal surface are recognized to be a real solution to this global
problem. The problem is complex. To realize the goal, it is necessary to perform a number of
interrelated tasks.
These include the methods and techniques of synthesis of BN graph. In the field of binary
boron-azo synthesis, real success has been achieved in the use of other nitrogen-containing
precursors instead of urea. Such variations are very interesting in scientific terms. However, it
would be a real technological shock to solve this problem by appropriately modifying a lot of
tonnage carbo-thermic synthesis of BN.
The task of studying the complex surface structure of the BN graph have still not
completely solved. In this paper, an attempt was made to consider only one component, a slit-
like porosity, with the example of nanosized powders. Studies have shown that other materials,
based on the turbostratic boron nitride, have other of pores types too.
92
The complexity of the pore surface structure is combined with its multifunctionality. The super-
hydrophobicity of graphene-like layers causes a high sorption ability to absorb oil products
from the water surface. The mechanical mobility of these layers affects the scale of variation of
the interplanar distances d002 from 0.342 to 0.40 nm and more. Atoms of nitrogen and boron
with broken chemical bonds, as a result of hydrolysis (Fig. 10), acquire the known ion-
exchange properties of chemisorption of cations of heavy metals and water-soluble dyes.
The next tasks, along with high and stable sorption characteristics, are the ways of regenerating
sorbents for their repeated use. The tasks have some ecological, but technological interest in the
concentration and processing of secondary raw materials.
In addition, finally, the tasks of categorization, standardization of finished products and
marketing pre-sales research.
Practical development of the research of a scientific direction allows solving an
unexpected problem. This is the use of BNgraph in hydrogen storage systems. If successful, such
a solution can be no more difficult than in similar acetylene-storage types.
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ПОРИСТА СТРУКТУРА ПОРОШКІВ НАНОРОЗМІРНОГО БОРАЗОГРАФЕНУ
В.А. Петрова, В.В. Гарбуз, Т.Ф. Лобунець, Т.В. Томила
Інститут проблем матеріалознавства ім. І. М. Францевича НАН України, вул.
Кржижанівського, 3 Київ, 03680, Україна, e-mail: wpetrowa@ukr.net
Досліджено структурні особливості порошків нанорозмірного боразографену (t-BNg.).
Результати показали, що в процесі очистки порошок t-BNg стає мікро-, мезо-пористим
(монодисперсним) з вузьким розподілом мезопори в діапазоні 3,82 – 4,12 нм, де більше
половини складають об'єм і близько 60% поверхні мезопор. Площа зовнішньої поверхні
порошків t-BNg ~ 30 м2 / г (t-метод), внутрішньої мезопор ~ 140 м2 / г (метод BJH).
Характеристики поверхні цього пористого тіла за теорією БЕТ завищені вдвічі.
Залишки бору оксонітриду у вигляді очищеного сублімату, порошку білого кольору, було
екстраговано з промитого та висушеного зразка t-BNg при температурі 540 К і тиску ≤
1,0 Па. Сублімат, згідно з даними хімічного аналізу та інфрачервоної спектроcкопії,
ідентифікований в припущенні циклічного димеру дигідро-дигідроксо-ди бороксазолу
складу H(OH)[(BON)2](OH)H. Запропоновано модель карбамідного синтезу нітриду бору,
як послідовність хімічних перетворень борато-карбамідних прекурсорів у вільно
радикальні боразо-пари (> В – N <).
95
ПОРИСТАЯ СТРУКТУРА ПОРОШКОВ НАНОРАЗМЕРНОГО БОРАЗОГРАФЕНА
В.А. Петрова, В.В. Гарбуз, Т.Ф. Лобунець, Т.В. Томила
Институт проблем материаловедения им. И.Н.Францевича НАН Украины ул.
Кржижановского, 3 Киев, 03680, Украина, e-mail: wpetrowa@ukr.net
Исследованы структурные особенности порошков наноразмерного боразографену
(t-BNg.). Результаты показали, что в процессе очистки порошок t-BNg становится
микро-, мезопористым (монодисперсным) с узким распределением мезопоры в диапазоне
3,82 - 4,12 нм, где более половины составляют объем и около 60% поверхности мезопор.
Площадь внешней поверхности порошков t-BNg ~ 30 м2 / г (t-метод), внутренней мезопор
~ 140 м2 / г (метод BJH). Характеристики поверхности этого пористого тела по
теории БЭТ завышены вдвое. Остатки оксонитрида бора в виде очищенного сублимата,
порошка белого цвета, было экстрагировано из промытого и высушенного образца t-BNg
при температуре 540 К и давлении ≤ 1,0 Па. Сублимат, согласно данным химического
анализа и инфракрасной спектроскопии, идентифицирован в предположении
циклического димера ди-гидро-ди-гидр-оксо-ди-бор-окс-азола состава
H(OH)[(BON)2](OH)H. Предложена модель карбамидного синтеза нитрида бора, как
последовательность химических превращений борат-карбамидных прекурсоров в
свободно радикальные боразо-пары (> В - N <).
|
| id | oai:ojs.pkp.sfu.ca:article-637 |
| institution | Surface |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-03-12T17:16:31Z |
| publishDate | 2017 |
| publisher | Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | surfacezbircomua/9d/054c1dd3af11603dd8fdd2b3c0bfd79d.pdf |
| spelling | oai:ojs.pkp.sfu.ca:article-6372018-12-01T11:25:21Z Porous structure of nano-dimensional boraso-graphenic powders Пористая структура порошков наноразмерного боразографена Пориста структура порошків нанорозмірного боразографену Petrova, A. V. Garbuz, V. V. Lobunets, T. F. Tomila, T. V. surface structure borazographene impurity boroxazole dissolution The structural features of surface of the nano-dimensional bor-azo-graphenic powders (t-BNg) after previous washing in boiling water were researched. The results showed that after process of purifier (washing) the powder’s surface of t-BNg characterized as slit-like micro-, mesoporous (monodispersed) structure with a narrow porous distribution in the range of 3.82 - 4.17 nm. The outer surface specific area of the powders of t-BNg according to “t - method” is 28.3 m2/g. The inner specific surface area of the mesopores is 141 m2/g (BJH method). The residues of boron oxonitride in the form of a purified sublimate, a white powder, extracted from a washed and dried sample of t-BNg at a temperature of 540 K and a pressure of ≤ 1.0 Pa. The sublimate, according to chemical analysis and infrared spectroscopy, was identified on the assumption of the cyclic dimer of di-hydro-di-hydroxo-di-bor-ox-azole of the composition of H(OH)[(BON)2](OH)H. The model of carbamide synthesis of boron nitride, as a sequence of chemical transformations of borate-carbamide precursors in a freely radical boron-pair (&gt; B - N &lt;), have proposed. Исследованы структурные особенности порошков наноразмерного боразографену (t-BNg.). Результаты показали, что в процессе очистки порошок t-BNg становится микро-, мезопористым (монодисперсным) с узким распределением мезопоры в диапазоне 3,82 - 4,12 нм, где более половины составляют объем и около 60% поверхности мезопор. Площадь внешней поверхности порошков t-BNg ~ 30 м2 / г (t-метод), внутренней мезопор ~ 140 м2 / г (метод BJH). Характеристики поверхности этого пористого тела по теории БЭТ завышены вдвое. Остатки оксонитрида бора в виде очищенного сублимата, порошка белого цвета, было экстрагировано из промытого и высушенного образца t-BNg при температуре 540 К и давлении ≤ 1,0 Па. Сублимат, согласно данным химического анализа и инфракрасной спектроскопии, идентифицирован в предположении циклического димера ди-гидро-ди-гидр-оксо-ди-бор-окс-азола состава H(OH)[(BON)2](OH)H. Предложена модель карбамидного синтеза нитрида бора, как последовательность химических превращений борат-карбамидных прекурсоров в свободно радикальные боразо-пары (&gt; В - N &lt;). Досліджено структурні особливості порошків нанорозмірного боразографену (t-BNg.). Результати показали, що в процесі очистки порошок t-BNg стає мікро-, мезо-пористим (монодисперсним) з вузьким розподілом мезопори в діапазоні 3,82 – 4,12 нм, де більше половини складають об'єм і близько 60% поверхні мезопор. Площа зовнішньої поверхні порошків t-BNg ~ 30 м2 / г (t-метод), внутрішньої мезопор ~ 140 м2 / г (метод BJH). Характеристики поверхні цього пористого тіла за теорією БЕТ завищені вдвічі. Залишки бору оксонітриду у вигляді очищеного сублімату, порошку білого кольору, було екстраговано з промитого та висушеного зразка t-BNg при температурі 540 К і тиску ≤ 1,0 Па. Сублімат, згідно з даними хімічного аналізу та інфрачервоної спектроcкопії, ідентифікований в припущенні циклічного димеру дигідро-дигідроксо-ди бороксазолу складу H(OH)[(BON)2](OH)H. Запропоновано модель карбамідного синтезу нітриду бору, як послідовність хімічних перетворень борато-карбамідних прекурсорів у вільно радикальні боразо-пари (&gt; В – N &lt;). Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2017-10-08 Article Article application/pdf https://surfacezbir.com.ua/index.php/surface/article/view/637 10.15407/Surface.2017.09.081 Surface; No. 9(24) (2017): Surface; 81-95 Поверхность; № 9(24) (2017): Поверхность; 81-95 Поверхня; № 9(24) (2017): Поверхня; 81-95 3154-8091 3154-8083 10.15407/Surface.2017.09 en https://surfacezbir.com.ua/index.php/surface/article/view/637/637 Авторське право (c) 2017 A.V. Petrova, V. V. Garbuz, T.F. Lobunets, T.V. Tomila |
| spellingShingle | Petrova, A. V. Garbuz, V. V. Lobunets, T. F. Tomila, T. V. Пориста структура порошків нанорозмірного боразографену |
| title | Пориста структура порошків нанорозмірного боразографену |
| title_alt | Porous structure of nano-dimensional boraso-graphenic powders Пористая структура порошков наноразмерного боразографена |
| title_full | Пориста структура порошків нанорозмірного боразографену |
| title_fullStr | Пориста структура порошків нанорозмірного боразографену |
| title_full_unstemmed | Пориста структура порошків нанорозмірного боразографену |
| title_short | Пориста структура порошків нанорозмірного боразографену |
| title_sort | пориста структура порошків нанорозмірного боразографену |
| topic_facet | surface structure borazographene impurity boroxazole dissolution |
| url | https://surfacezbir.com.ua/index.php/surface/article/view/637 |
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