Loaded carbon shell encapsulated transition metal and ZnIn2S4 on carbonized paper for enhanced photocatalytic hydrogen production

Solar-driven semiconductor photocatalysis water splitting is considered a green and efficient method for hydrogen production. But the severe recombination of photogenerated carriers limits the efficiency of hydrogen production. The introduction of transition metal co-catalyst can form an internal electric field (IEF) with semiconductor to achieve efficient directional transfer of photogenerated electron-holes. However, the aggregation of transition metal co-catalyst and the formation of metal-hydrogen bonds are still the main problems for limiting hydrogen production efficiency. Here, metal–organic framework (MOF) derived porous carbon encapsulated transition metal Fe (Fe@C) and ZnIn₂S₄ are loaded on carbonized cellulose fibers (CCF) to construct composite paper for photocatalytic water splitting into hydrogen. The MOF-derived carbon skeleton can provide high conductivity and disperse Fe co-catalyst for increasing the active sites. Moreover, the encapsulation of Fe in the 3D carbon skeleton can avoid the formation of metal-hydrogen bonds and improve the hydrogen adsorption and desorption capacity. The CCF as a carrier is beneficial to improve the dispersibility and reusability of Fe@C and ZnIn₂S₄. The hydrogen evolution rate of the composite paper is as high as 63.8 mmol h⁻¹ g⁻¹ under visible light irradiation. After 5 photocatalytic cycles, the hydrogen evolution rate remains at 94.2 % and the loading state of Fe@C and ZnIn₂S₄ on CCF is maintained. This work provides a new idea for fabrication of high-efficient photocatalytic paper, and develops the application potential of MOF derivatives in photocatalysis.