Hierarchically Periodic Macroporous Niobium Oxide Architecture for Enhanced Hydrogen Evolution

Abstract

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.

Interconnected Periodic Macroporous NaNbO3 for High-Efficiency Solar-Driven Photocatalytic Hydrogen Evolution

“…Generally, a smaller diameter of the template sphere results in a larger specific surface area and more active sites. However, reducing the diameter of the template sphere leads to a narrower pore structure and nanoscale framework of the inverse opal structured NaNbO 3 obtained, which may pose challenges for mass transfer . The synthesized PMMA spheres exhibit uniform particle size and high dispersion, with diameters of 220 ± 4, 310 ± 3, and 370 ± 6 nm (Figure b 1 –d 1 ).…”

“…However, reducing the diameter of the template sphere leads to a narrower pore structure and nanoscale framework of the inverse opal structured NaNbO 3 obtained, which may pose challenges for mass transfer. 25 The synthesized PMMA spheres exhibit uniform particle size and high dispersion, with diameters of S1), yielding values of 28.7, 27.4, and 22.3 m 2 g −1 , respectively. The PM NaNbO 3 -310 exhibits the highest photocatalytic performance among the PM NaNbO 3 samples with varying pore sizes, achieving a rate of 10.04 mmol g −1 h −1 (Figure 2g).…”