Efficient hydrogenation of cinnamaldehyde to 3-phenylpropanol on Ni/NiS-modified twin Zn0.5Cd0.5S under visible light irradiation

Solar-energy-driven organic synthesis over semiconductor materials is considered to be an environmentally friendly strategy, but it is still confronted with challenges of low reaction efficiency and high catalyst cost. In this paper, we report a non-precious metal-modified nano-twin crystal ZnxCd1−xS (ZCS) photocatalyst, a Ni/NiS–ZCS composite, which can almost completely convert cinnamaldehyde (CAL) into 3-phenylpropanol (HCOL), and achieves a yield of >80% for HCOL and an AQE 20.69% under 420nm light irradiation in 80 min reaction time without any additional hydrogen source. As far as we know, this is a typical example for developing visible-light-driven photocatalysts for reducing cinnamaldehyde to 3-phenylpropanol. The high photoactivity and stability of Ni/NiS–ZCS make it an ideal candidate of photocatalysts for future practical applications. The high catalytic activity of Ni/NiS–ZCS could be ascribed to its unique heterojunction with appropriate band potentials and effective charge separation–transportation. In situ isotope labelling HPLC-MS analysis revealed the presence of intermediate COL, and the reduction mechanism of CAL follows a CAL → COL → HCOL route when using water and ethanol as hydrogen donors.