Largely Enhanced Photocatalysis Process by Contact-Electro-Catalysis for Efficient and Eco-Friendly Recovery of Gold

Precious metal recovery has become increasingly critical due to resource scarcity, while conventional extraction methods often suffer from low efficiency and pollution problem. Here, this work proposes an efficient and environmentally friendly catalytic strategy based on the integration of contact-electro-catalysis (CEC) and photocatalysis. The composite microsphere catalyst is fabricated by using low temperature co-firing TiO₂/PTFE particles, which have an average diameter of ≈10 µm and expose both TiO₂ and PTFE active sites on its surface, enabling dual CEC-photocatalytic synergy reactions. Compared to pristine TiO₂ catalyst with similar weight, this composite microsphere catalyst exhibits a tenfold enhancement in gold extraction efficiency from electronic waste. This high-performance leaching system operates under mild conditions, alleviating the need for traditional strong oxidants and offering potential for industrial application. Density functional theory (DFT) calculations further reveal that charge transfer from H₂O to PTFE and subsequently into TiO₂, with favorable energy band alignment between PTFE and TiO₂ ensuring efficient carrier hopping and enhanced photocatalytic activity. This composite catalytic strategy based on organic-inorganic microsphere catalysts may be extended to areas like wastewater treatment, organic synthesis, and industrial waste valorization.