Hierarchically porous TiO2 supported anisotropic plasmonic Cu2-xS photocatalyst for accelerated hydrogen evolution and CO2 reduction to MeOH

Abstract

In this report, a facile precipitate (water/ethylene glycol) strategy has been employed for constructing a robust heterostructured photocatalyst, Cu2-xS/HPT (CHPT). The synergistic HPT stabilized on plasmonic Cu2-xS (0 < x < 1) acts as a bifunctional catalyst, enabling efficient separation of photoexcited charges in accelerated hydrogen evolution and selective conversion of CO2 to MeOH and resulting in a superior hydrogen efficiency of 4.43 mmol g−1h−1 (AQY 6.16%) and CO2 reduction to MeOH (2.2 mmol g−1 h−1). The integrated Cu2-xS/HPT decreases the band potential to 2.30 eV and exhibits an impressive photocurrent response (132 μA cm−2) without onset bias and significant corrosion resistance with low Tafel slope of 155 mV.dec−1. The findings of the photoluminescence and TCSPC experiments reveal that charge-carrier transfer is both efficient and effective, with less charge recombination occurring throughout the reduction phase. Photochemical reduction is facilitated by exposed active sites at HPT wormhole fibrous pore vertices and edges, in addition to an optimum Cu1.8S loading. The experimental and DFT studies complement each other for superior catalytic performance.