Double 2-dimensional H₂-evoluting catalyst tipped photocatalyst nanowires: A new avenue for high-efficiency solar to H₂ generation

Asymmetric or symmetric metal-tipped one-dimensional (1D) semiconductors are promising systems for efficient photocatalytic reactions such as solar-to-fuel conversion because of ultrafast exciton dynamics that arise at the specific heterostructure interface. However, synthesizing such unique nanostructures experiencing colloid growth on noble metal that has faced a formidable challenge in practical application because these synthesis conditions are not suitable to deploy in mass production. Here, we report the gram-scale mass production of symmetric MoS₂-tipped CdS nanowires (S-MtC NWs) via edge-terminated attachment in a binary solvent. The factors influencing the formation of symmetric heterostructures are investigated by varying the types of precursors, initial concentration, and solvent composition. Under visible-light irradiation (λ≥420 nm), the S-MtC NWs exhibit superior photocatalytic H₂ evolution activity (12.6 mmol/g/h) compared to common Pt/CdS NWs (2.6 mmol/g/h), corresponding to an apparent quantum yield of 37.6% at 420 nm. This impressive photocatalytic ability is ascribed to spatially separated redox-active sites in the S-MtC NWs, in which the reduction and oxidation sites are at the MoS₂ tip and the CdS stem, respectively. Additionally, it is found that the length of CdS NWs as higher aspect ratio as possible could get better photocatalyst H₂ performance. The symmetry of 2D MoS₂ tips and 1D CdS NWs may provide advanced avenues for specific co-catalyst decoration, enabling co-catalysts to be selectively located at reduction or oxidation sites for other targeted solar artificial syntheses.