Performance of amine-modified CdS-D@ZIF-8 nanocomposites for enhanced photocatalytic H2 evolution

The exploration of an efficient photocatalyst for H2 evolution directly from water splitting is highly desirable due to the current environmental and energy situation. The present work successfully used a solvothermal method to synthesize organic-inorganic CdS-diethylenetriamine (CdS-D) nanorods (NRs). The amine-modified CdS-D@ZIF-8 nanocomposite materials were prepared using the self-assembly method with different ZIF-8 nanocrystals (NCs) weight ratios. At λ ≥ 420 nm wavelength, the optimized CdS-D@ZIF-8 (CZ-2) nanocomposite with 5.0 wt% loading of ZIF-8 NCs showed the highest performance of 2293.9 μmol g−1 h−1 H2 evolution and an apparent quantum yield (AQY) of 4.95%. The CZ-2 nanocomposite's activity was 114.69, 5.25, and 1.32 times higher than that of ZIF-8 NCs (20.0 μmol g−1 h−1), CdS-D NRs (436.4 μmol g−1 h−1) and 1.0 wt% Pt/CdS-D (1737.3 μmol g−1 h−1), respectively. The cyclic photostability of the prepared CZ-2 nanocomposite remained unchanged after six consecutive cycles. The UV-DRS, electrochemical measurements, and Mott-Schottky (MS) analysis were performed to explain the band edge positions for CdS-D NRs and ZIF-8 NCs. The detailed S-scheme charge transfer mechanism of the as-prepared catalysts was also studied using the density functional theory (DFT). This work provides vital information for the controllable synthesis of ZIF-8-modified S-scheme nanocomposites for solar energy utilization.