One-dimensional D-π-A conjugated polymers for photoenhanced gold recovery from e-waste

Abstract

In principle, photocatalytic Au(III) reduction from e-waste using sunlight could provide a cleaner and more efficient alternative strategy to existing processes. Two-dimensional (2D) conjugated polymers are often employed for photocatalytic systems due to their structural diversity and stability. However, the efficiency of active site utilization in 2D materials still needs to be improved because the catalytic reduction centers are located in the basal layer and it is difficult for Au(III) to access them. Herein, we demonstrate the application of D-A and D-π-A type one-dimensional (1D) conjugated polymers for the photoenhanced gold recovery from electronic waste. The two synthesized 1D conjugated polymers, named BTP-DET (D-π-A type) and BTP-TDB (D-A type), exhibit a wide light absorption range and excellent chemical stability. Benefiting from the superior charge separation and migration efficiency of the D-π-A skeleton, BTP-DET exhibits a small optical band gap of 1.60 eV, which is significantly smaller than that of BTP-TDB (1.78 eV), and thus enables the extraction of the gold with a higher capacity of BTP-DET (2580.8 mg g−1) under visible light, than the BTP-TDB (2072.7 mg g−1). This work paves the way for exploring low dimensions of conjugated polymers for photocatalysis.