Template Quality Dependent Conversion Synthesis of Boron Nitride Coated Graphene Hybrid Aerogels for Ultrasensitive and Selective Ammonia Sensing

Abstract

Recently, hexagonal boron nitride (h-BN) nanomaterials, e.g., nanosheets and nanotubes, have been predicted to be effective materials for reversible gas adsorption with high selectivity once charged. However, despite the encouraging theoretical predictions, sensing with h-BN is difficult to realize experimentally due to its electrically insulating nature stemming from its large band gap. In this research, the controlled synthesis of high surface area hybrid h-BN/graphene aerogel is reported, using high-quality graphene as a template, and its application for selective gas sensing. It is discovered for the first time in this system that the difficulty of conversion in template synthesis of h-BN is positively correlated with the quality of the carbon template, an observation that is verified on both graphene nanosheets and carbon nanotubes. The application of this hybrid material for gas sensing yields ppb level of detection limit and high selectivity for NH₃. Through density functional theory calculations, the adsorption energy and charge transfer between NH₃ molecules and aerogel are greatly enhanced. Therefore, this innovative approach promises new possibilities for the application of h-BN in gas sensing, with the potential to play a significant role in gas capture, environmental monitoring, and other related fields.