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

- Symmetric 2D tipped 1D heterostructured nanowires were synthesized.
- The tipped structure exhibited the spatially separated redox-active sites.
- Theoretical simulation demonstrated one order of magnitude decrease in energy barrier.
- The photocatalytic performance of symmetric heterostructure was superior to asymmetric counterpart.

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.

Symmetric 2D tipped 1D heterostructured nanowires synthesized by edge-terminated attachment exhibit efficient spatial charge separation effect and the longer the better photocatalytic activity, resulting in photocatalytic H2 activity of 12.6 mmol/h·g with excellent long-term durability (>10 h) without additional passivation under visible light (λ≥420 nm).178