Solar-driven dual-function Ag/Au@CN photocatalyst for simultaneous hydrogen production and pollutant reduction from industrial wastewater

Abstract

A dual-function Ag/Au@CN photocatalyst was fast synthesized via simple thermal treatment and photodeposition for simultaneous hydrogen (H<inf>2</inf>) production and pollutant reduction from industrial wastewater under solar light irradiation. The CN photocatalyst with a co-metal decoration exhibited higher photocatalytic activity than those with a single-metal decoration and pristine CN photocatalyst. Among all co-metal decorated CN photocatalysts, the 0.13Ag/Au@CN sample achieved the highest H<inf>2</inf> production rate, approximately 95.6, 1.3, and 9.8 times higher than those of CN, Au@CN, and Ag@CN photocatalysts, respectively. This enhancement is attributed to the optimally balanced Au and Ag contents in the CN structure, which can facilitate strong light-harvesting ability, effective reaction sites, and efficient charge transport. Optimal conditions, including wastewater dilution, type and concentration of hole scavengers, and photocatalyst loading, further accelerated the photocatalytic activity. The principal reactive oxygen species (ROS) involved in photocatalytic pollutant reduction via the Ag/Au@CN photocatalyst were the superoxide (O<inf>2</inf>^•⁻) radicals and followed by photogenerated holes (h⁺). This work highlights the synthesis of an efficient dual-function photocatalyst through a simple approach for simultaneous energy production and industrial wastewater remediation under solar light irradiation, offering a sustainable strategy for industrial wastewater management.