Cd 1– x Zn x S Nanorod Solid Solutions with Sulfur Vacancies as Effective Electron Traps for Highly Efficient Photocatalytic Hydrogen Evolution

In this work, Cd 1– x Zn x S nanorod solid solutions with the features of sulfur (S) vacancies and a single phase ( x ≤ 0.2) or two phases ( x ≥ 0.3) have been successfully prepared using a facile hydrothermal process. Without any assistance of noble metals as a cocatalyst, all prepared solid solutions present in either a single phase or two phases exhibit remarkably higher photocatalytic H 2 evolution than pure single-phase CdS in Na 2 S/Na 2 SO 3 aqueous solution. The effects of the incorporation of Zn 2+ into the CdS lattice on the phase structure and constitutions, optical properties, electronic band structure, Fermi levels, and S vacancies’ ability to trap electrons were investigated in detail. It was revealed that the formation of the Cd 1– x Zn x S solid solution upgrades the Fermi level closer to the energy level of S vacancies. As a result, the S vacancies near the Fermi level become an effective electron trap center to inhibit the recombination of photogenerated electron–hole pairs, resulting in the enhanced photocatalytic H 2 evolution. This study might open up a new avenue for the understanding and design of CdS-based solid solutions with efficient photocatalytic H 2 evolution from water splitting.