| Boron nitride?BN?,as a new type of nanomaterials with a structure similar to graphite,has a great market prospect.Boron nitride exhibits better physicochemical properties such as higher temperature resistance,better oxidation resistance and stronger chemical resistance compared with graphite materials,which has gradually attracted the attention of researchers in recent years.The preparation and properties of boron nitride-based nanomaterials were systematically studied in our study.We have prepared boron nitride nanosheets,boron nitride quantum dots and composite materials.In addition,the properties of boron nitride based composite materials in different fields?adsorption,gas sensing,photocatalysis?were also studied.The specific research contents are as follows:?1?The preparation and adsorption performance of hierarchical porous boron nitride nanosheetsThe hierarchical porous boron nitride nanosheets?hp-BNNSs?were prepared by high temperature calcination of the precursor which were obtained from the recrystallization process using boric acid and urea as the raw materials.The as-prepared hp-BNNSs have a large specific surface area?1145 m2/g?and pore volume?0.59 cm3/g?.In addition,there have numerous larger diameter mesopores?40 nm?in the as-prepared hp-BNNSs,which is benefit to further improve the adsorption performance.The prepared hp-BNNSs showed versatile adsorption for water treatment:at first,the negative surface charge of hp-BNNSs that can be attributed to the negatively charged ionized B-O bonding,which are not only enhance the hydrophilicity between hp-BNNSs and pollutant solution,but also can attract the cationic pollutant molecules,such as cationic dyes and heavy metal ions.In addition,the hp-BNNSs with numerous polar B-N bonds can further improve the adsorption performance for heavy metal ions.Finally,since numerous?systems exist on the surface of hp-BNNSs,the non-electrostatic?-?interactions could occur with pollutant molecules?TC?which contain aromatic rings,that lead to the hp-BNNSs also exhibit good adsorption performance for this kind of pollutants.?2?The preparation and gas sensing performance of BNQDs/Sn O2compositeBoron nitride quantum dots?BNQDs?,Sn O2 nanoflowers and BNQDs/Sn O2 composites were prepared by a simple hydrothermal method in order to detect the gas sensing performance of ethanol and H2S.In addition,the mechanism of the presence of BNQDs on the gas sensing performance was discussed.The research results showed that the BNQDs/Sn O2 sensor not only reduced the optimal operating temperature for ethanol,but also enhanced the response value and response/recovery time to ethanol compared with pure Sn O2sensor,which were realized rapid response and recovery to ethanol?5s/8s?.Moreover,BNQDs/Sn O2 sensor achieved the detection of H2S at room temperature?30°C?,and it also showed good selectivity for H2S.These phenomena can be attributed to the functionalization of BNQDs:the modification of BNQDs on the surface of Sn O2 nanoflowers made BNQDs become new active sites for electron capture,which not only can accelerate the speed of electron transport,but also generate more reactive oxygen species,thereby can further improve the gas sensing performance.In addition,the small size effect of BNQDs also played an important role in improving the gas sensing performance.The average size of BNQDs was around 5 nm,which were less than the thickness of the Sn O2depletion layer?2Ld=6 nm?.The electron transit process was controlled by the depletion layer,thereby the composite material showed more excellent gas sensing performance.?3?The preparation and photocatalytic performance of BCN/Ag3PO4compositeAt first,C3N4 nanosheets were obtained from urea and used as the springboard,then the C doped BN nanosheets?BCN nanosheets?were prepared by calcining the mixture of C3N4nanosheets and boric acid at high temperature.Secondly,a novel BCN/Ag3PO4 composite was successfully prepared via electrostatic driven self-assembly and ion exchange processes.As shown in SEM,it can be seen that the BCN nanosheets were wrapped by Ag3PO4 nanoparticles successfully.In addition,the size of the Ag3PO4 nanoparticles were effectively controlled due to the limitation of the BCN nanosheets,they exhibited smaller size and more uniformly distribution compared with the pure Ag3PO4 nanoparticles.BCN nanosheets can act as the electron consumers to capture the photogenerated electrons from Ag3PO4nanoparticles due to the excellent electron transfer ability.That can not only prevent the photocorrosion of Ag3PO4 nanoparticles due to the presence of photogenerated electrons,but also the captured electrons can react with oxygen to further take part in the photocatalysis process,which can further improve the photocatalytic performance of the BCN/Ag3PO4composite materials. |
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