Hierarchically Periodic Macroporous Niobium Oxide Architecture for Enhanced Hydrogen Evolution

The fabrication of periodic macroporous (PM) in Nb₂O₅ via morphological control is crucial for improving the photocatalytic hydrogen evolution efficiency. In this study, Nb₂O₅ with PM is synthesized using a straightforward colloidal crystal templating approach. This material features an open, interconnected macroporous architecture with nanoscale walls, high crystallinity, and substantial porosity. Extensive characterization reveals that this hierarchically structured Nb₂O₅ possesses abundant surface active sites and is capable of capturing light effectively, facilitating rapid mass transfer and diffusion of reactants and markedly suppressing the recombination of photoexcited charge carriers. Macroporous Nb₂O₅ exhibits superior water-splitting hydrogen evolution performance compared with its bulk and commercial counterparts, achieving a hydrogen production rate of 405 µmol g^-1 h^-1, surpassing that of bulk Nb₂O₅ (B-Nb₂O₅) and commercial Nb₂O₅ (C-Nb₂O₅) by factors of 5 and 33, respectively. This study proposes an innovative strategy for the design of hierarchically structured PM, thereby significantly advancing the hydrogen evolution potential of Nb₂O₅.