Cu-In₂S₃ nanorod induced the growth of Cu&In co-doped multi-arm CdS hetero-phase junction to promote photocatalytic H₂ evolution

The interface defects caused by lattice mismatch between semiconductors and the homogeneous doping of dopants in host semiconductors without layered structure are the challenges in the construction of high performance photocatalysts. Herein, a smart template induced in-situ growth method is developed to synthesize a quantum dot level Cu&In co-doped CdS (CuIn-CdS) hetero-phase junction with multi-arm nanorod morphology for the first time. Due to the in-situ growth of CdS induced by Cu-doped In₂S₃ nanorods, the homogeneous doping of Cu and In in CdS is easily realized, which efficiently expands the light absorption ability of CdS. Moreover, owing to the hetero-phase junction formed between hexagonal and cubic CdS rather than heterostructure, the lattice mismatch and the interface defects are greatly minimized, which effectively facilitates the separation and transfer of photogenerated charge carriers. As a result, the optimal CuIn-CdS exhibits a photocatalytic H₂ evolution rate of 105.44 mmol/g/h (corresponding to the apparent quantum efficiency (AQE) of 32.72% at 400 nm), which is about 55.0, 10.9 and 9.7 times higher than that of pristine CdS, Cu-CdS and In-CdS, respectively. This work provides a new way to overcome interface defects and realize homogeneous doping at the same time for exploring new photocatalysts with high performance.