Periodic Multi-Scale Macroporous Niobium Oxide Constructed for Enhanced Photocatalytic Hydrogen Evolution

The efficient utilization of the skeletal structure in periodic macropores typically necessitates thinner walls, which correspond to smaller pore size structures. However, the effective mass transfer requires larger pore sizes. Consequently, achieving a balance between optimal skeleton utilization and rapid mass transfer has emerged as a key challenge for periodic macroporous materials. Regulating structure to create periodic multi-scale macropores in Nb₂O₅ is a crucial strategy for enhancing photocatalytic hydrogen evolution efficiency. In this study, an innovative multiscale periodic polymethyl methacrylate (PMMA) template is designed and employed to synthesize periodic multi-scale macroporous Nb₂O₅ (PMM Nb₂O₅). This distinctive porous structure markedly enhances the transfer efficiency of reactants and products, as well as the accessibility of active sites. PMM Nb₂O₅ demonstrates superior photocatalytic performance, achieving a hydrogen production rate of 2.33 mmol g^-1·h^-1-4 times higher than that of periodic macroporous Nb₂O₅ with uniform pore size and 12.26 times greater than bulk Nb₂O₅ (B-Nb₂O₅). This study introduces an innovative strategy for constructing periodic multi-scale macroporous materials, thereby substantially augmenting the hydrogen evolution potential of Nb₂O₅.