Engineering hollow Ni–Fe-based mesoporous spherical structure derived from MOF for efficient photocatalytic hydrogen evolution

Endowing photocatalyst with functional nanostructure can effectively improve its performance towards solar energy conversion. Here, a unique Ni–Fe-based mesoporous hollow spherical nanostructure (NiFeOx/NC-t) was facilely constructed via the direct thermal decomposition of Ni-BTC@PBA composites. The hybrids consist of in-situ formed nitrogen-enriched carbon layers constituting the mesoporous walls of hollow spherical, and amorphous NiFeO_x nanoparticles and a small fraction of FeNi₃ are embedded on the spherical walls during carbonization. After loading EY molecules on NiFeOx/NC-t as solar light absorbers, an optimal photocatalytic hydrogen evolution rate of 5352.7 μmol g⁻¹ h⁻¹ was achieved with excellent stability under visible light (λ > 420 nm) in the absence of co-catalyst. The excellent photocatalytic activity was revealed to be ascribed to: ⅰ) mesoporous hollow spherical structure having a large surface area, thus exposing more active sites; ⅱ) efficient injection of photo-generated electrons from excited EY⁻ into NiFeO_x and FeNi₃ by the bridge of high-conductive nitrogen-enriched carbon layer. In brief, the structural and compositional features synergistically strengthen the photocatalytic activity of NiFeOx/NC-t. It is worth noting that MOF-derived route can significantly simplify the preparation process of mesoporous hollow spherical nanostructure. This work provides an approach for facile preparation of versatile photocatalysts with high efficiency for solar energy conversion.