Novel visible-light-driven direct Z-scheme CdS/CuInS2 nanoplates for excellent photocatalytic degradation performance and highly-efficient Cr (VI) reduction

A series of visible-light-driven direct Z-scheme CdS/CuInS2 nanoplates were fabricated by a facile one-step hydrothermal method, and the molar ratio of CdS to CuInS2 was optimized. The highest visible-light photocatalytic degradation activity of Z-scheme (1: 0.03) CdS/CuInS2 heterojunction is about 4 times than that of pure CuInS2, which is due to the narrowest band gap, the largest BET surface area, the most efficient charge separation and transfer, and the synergistic effect between CdS and CuInS2. Meanwhile, Z-scheme (1: 0.03) CdS/CuInS2 heterojunction also exhibits excellent photocatalytic reduction activity with almost 100% of aqueous Cr (VI) reduction efficiency in absence of hole scavengers after 60 min. The special significance is that Z-scheme (1: 0.03) CdS/CuInS2 heterojunction shows excellent stability in five degradation cycles, and can effectively treat real pharmaceutical wastewater with 76.5% COD removal efficiency with aid of H2O2 in 13 h, indicating that Z-scheme CdS/CuInS2 has a promising prospect in real pharmaceutical wastewater treatment.