Few-Layered Graphene-like Boron Nitride: A Highly Efficient Adsorbent for Indoor Formaldehyde Removal

Highly porous boron nitride (BN) composed of a flexible network of hexagonal BN nanosheets was synthesized via thermal treatment of a boric acid/urea mixture. The as-prepared sponge-like BN displayed fast adsorption rates and ultrahigh adsorption capacities for gaseous formaldehyde (HCHO), e.g., 19 mg/g in equilibrium with approximately 20 ppm of HCHO in air, which is an order of magnitude higher than those of other tested materials, including commercial hexagonal BN and various metal oxides. The superb HCHO adsorption performance of the porous BN is mainly due to its large specific surface area (627 m2/g), as well as the abundant surface hydroxyl and amine groups. Moreover, chemisorption can occur on the BN layers and contribute to the high HCHO uptake capacity via Cannizzaro-type disproportionation reactions, during which HCHO is transformed into less toxic formic acid and methanol. This porous BN is a promising adsorbent for indoor HCHO removal and may serve as the support for highly efficient HCHO decomposition catalysts.