Tuning interfacial sequence between nitrogen-doped carbon layer and Au nanoparticles on metal-organic framework-derived TiO₂ to enhance photocatalytic hydrogen production

Multicomponent photocatalysts loaded with two interfacial co-catalysts may exhibit greater improvement in hydrogen evolution than those without any co-catalyst or with only one co-catalyst. Two major issues should be solved in developing such photocatalysts. One is how to obtain photocatalysts with two interfacial co-catalysts by a controllable approach. The other is what are key factors affecting photocatalytic activity. In this study, TiO₂-based photocatalysts loaded with two interfacial co-catalysts, i.e., N-doped carbon layer coating on Au nanoparticle-embedded TiO₂ and Au nanoparticles attaching on N-doped carbon layer coated TiO₂, were prepared by thermal degradation of a Ti-based metal-organic framework, where the composition and interface sequence of N-doped carbon layer and Au nanoparticles were carefully engineered. Experimental results conclude that the Au/TiO₂ interface, formed by a direct contact between Au and TiO₂, is key factor to enhance the separation efficiency of photogenerated electrons/holes, and coating N-doped carbon layer on this Au/TiO₂ interface achieves a synergistic effect in enhancing photocatalytic H₂ production.