Novel synthesis of boron nitride nanosheets from hexagonal boron nitride by modified aqueous phase bi-thermal exfoliation method

Abstract

The hexagonal Boron Nitride Nanosheets (BNNSs) were derived from commercially available hexagonal Boron Nitride (h-BN) by the pressure assisted aqueous bi-thermal method. The few-layered BNNS could be identified from PXRD measurements that showed lower peak intensity for (002) plane when compared to that of bulk h-BN. The characteristics of h-BN and BNNSs were further evaluated by using different analytical methods and instruments like PXRD, UV–Visible DRS, FTIR, FESEM and HRTEM etc. The Boron Nitride nanosheets synthesized using this green exfoliation protocol provided nanosheets with improved band gap. The assessment from UV–Vis DRS spectra of Boron Nitride nanosheets supported this opinion. The band gap energy deduced from UV–Vis DRS measurement showed rise in the band gap energy from 5.4 for h-BN to 5.8 eV for BNNSs implying improved insulating properties of BNNSs. The Boron Nitride Nanosheets were thus found to act as better insulators than the parent material h-BN. This work described a green, low cost, facile and scalable technique for exfoliation of commercially available hexagonal Boron Nitride.