Synthesis of Type-S Ni3S4/ZnCdS Quantum Dots via Constitution Controller l-Cysteine for Photocatalytic H2 Evolution

Abstract

Designing and synthesizing highly efficient hydrogen-producing catalysts using morphological control techniques and path structure layouts based on photogenerated electron migration can effectively address environmental pollution and promote clean energy development. However, exploitating stabilized photocatalysts with exceptional photocatalytic performance remains challenging. Herein, Ni₃S₄/ZnCdS quantum dots (NZCS QDs) were synthesized at room temperature for high-efficiency photocatalytic H₂ production. l-Cysteine (l-Cys) as constitution controller controlled the composition of the NZCS QDs by limiting their growth, and the photogenerated electrons of the cocatalyst Ni₃S₄ rapidly captured the photogenerated holes of ZCS QDs. This process resulted in a significant increase in the H₂ evolution rate of NZCS QDs up to 5.03 mmol·g^–1·h^–1, which was 8.98 times greater than that of CdS QDs. The experimental findings indicated that the increased rate of H₂ production was primarily attributed to the higher number of active sites, faster type-S photogenerated electron–hole separation driven by an internal electric field, and enhanced charge reaction efficiency of the NZCS QDs. This study presents a credible synthetic approach for NZCS QDs and offers a solution to improve the efficiency of photocatalytic reactions based on ZnCdS.