Photoelectrochemical Water Splitting Of Cu₂O/CuO Photocathodes For Hydrogen Evolution Reaction

In today’s society,energy shortages and environmental problems caused by fossil fuels need to be solved urgently.The development and utilization of hydrogen energy is an important way to solve energy and environmental problems at the same time.Among many methods,the method of photoelectric catalytic water splitting to produce hydrogen using solar energy has important application prospects in solving energy problems.In recent years,copper-based composite semiconductor materials have become one of the hot spots in photoelectric catalytic hydrogen production technology due to their large absorption coefficient,suitable optical band gap and low toxicity.This paper takes Cu₂O/CuO composite electrode as the main research object,and uses ion doping,carbon composite and other methods to improve its photoelectric catalytic efficiency.Cu₂O/CuO/CF composite photoelectrodes were fabricated on foamed copper（CF）substrates by a rapid flame combustion method and their photoelectrocatalytic properties were discussed.Cu₂O precursor materials were prepared by hydrothermal method,and Cu₂O/CuO/CF semiconductor materials with heterostructures were rapidly synthesized by gas flame annealing method.Morphology characterization found that the morphology of the sample will change greatly after high temperature flame annealing.At the same time,the Cu₂O/CuO/CF-5 photoelectrode material with high photoelectric catalytic activity was obtained by controlling the flame time,and its photocurrent reached-4.2 m A/cm~2@0 V_RHE.Studies have shown that copper-based heterostructures can significantly inhibit the recombination of photogenerated charges.The C-Cu₂O/CuO/CF composite electrode was successfully synthesized by candle flame combustion.The Cu₂O/CF obtained by the hydrothermal method was used as the precursor,and carbon was formed on the electrode surface after candle flame annealing.After photoelectrochemical tests,it was found that the photocurrent of the C-Cu₂O/CuO/CF photocathode can reach-1.2 m A/cm~2@0V_RHE,showing a good water reduction ability.Further photoelectrochemical characterization and testing showed that carbon recombination can effectively improve the charge transfer ability,and the recombination of CuO also increases the carrier concentration.Taking Ti ion-doped Cu₂O/CuO/CF photocathode as the research object,the enhancement of photocatalytic activity by ion doping is discussed.By optimizing the doping amount of Ti ions,the photocurrent of the photocathode with the optimal ratio of Ti:Cu₂O/CuO/CF is about-5.4 m A/cm~2@0 V_RHE.Through modern analysis and testing methods,it is shown that Ti doping can enhance the absorbance of semiconductor materials,narrow the band gap to obtain better light absorption efficiency,and at the same time,the carrier concentration and separation efficiency have been greatly improved.The CuFe₂O₄/CuO composite photocathode was prepared by combining electrochemical deposition and flame combustion,and its photocatalytic activity was compared with that of CuFe₂O₄and CuO.The research shows that the composite photocathode exhibits good photocathode performance,and the photocurrent of the CuFe₂O₄/CuO photocathode is about-1.5 m A/cm~2@0 V_RHE.Experiments show that the composite structure formed by CuO and CuFe₂O₄can effectively inhibit the recombination of carriers and make it have strong water reduction ability.