Plasmonic Ag nanoparticles decorated copper-phenylacetylide polymer for visible-light-driven photocatalytic reduction of Cr(VI) and degradation of PPCPs: Performance, kinetics, and mechanism

Highlights: • A plasmonic Ag/PhC₂Cu photocatalyst was synthesized via a facile method. • Ag/PhC₂Cu possessed efficient photocarrier separation and solar-energy-conversion. • Ag/PhC₂Cu exhibited outstanding photocatalytic redox activity under visible light. The development of efficacious photocatalysts for the elimination of contaminants in water remains a challenge. Herein, a promising Ag nanoparticles-decorated copper-phenylacetylide (Ag/PhC₂Cu) plasmonic photocatalyst was fabricated for the reduction of hexavalent chromium (Cr(VI)) and degradation of pharmaceutical and personal care products (PPCPs). Typically, the optimized 5Ag/PhC₂Cu could rapidly reduce Cr(VI) (98.1% within 12 min), and degrade norfloxacin (NOR) (100% within 40 min) with a 56.2% mineralization rate under visible light. The superior photocatalytic activity of Ag/PhC₂Cu was attributed to the synergistic effects of the highly reducing photoinduced electrons conferred by the PhC₂Cu (−1.98 eV), and Ag nanoparticles in promoting photocarrier separation and enhancing solar-energy-conversion efficiencies. Subsequently, the photocatalytic reaction mechanism of Ag/PhC₂Cu was investigated. It was found that e^- and O₂^{• -} were the main reactive species for Cr(VI) reduction, while O₂^{• -} and h⁺ were primarily responsible for the degradation of NOR. Of note, the Ag/PhC₂Cu system could effectively generate H₂O₂ and partially decomposed it to • OH, which might be involved in NOR mineralization. This study not only demonstrates a highly active photocatalytic system for the remediation of environmental pollution and sustainable solar-to-chemical energy conversion, but contributes to the future exploration of multifunctional plasmonic photocatalysts.