Porous Hexagonal Boron Nitride Sheets: Effect of Hydroxyl and Secondary Amino Groups on Photocatalytic Hydrogen Evolution

Hexagonal boron nitride ( h -BN), an emerging two-dimensional material, has attracted great attention in various fields. However, due to its large band gap (ca. 6 eV), h -BN has not yet been exploited as a photocatalyst. Here, we demonstrate a porous h -BN sheets with rich hydroxyl (-OH) and secondary amino (-NH) groups, which can effectively decrease the band gap of h -BN. Porous h -BN sheets were synthesized via combustion of boron acid and urea at high temperature under nitrogen atmosphere. The as-obtained porous h -BN has a narrower band gap and a higher photocatalytic activity on hydrogen evolution than commercial h -BN. To further understand this photocatalytic performance, we investigated the groups, structure, and related optical and electrochemical properties for both porous and commercial h -BN. This work holds promise for h -BN to be used in the photocatalysis field.