Improving Separation Efficiency of Photogenerated Charges through Combination of Conductive Polythiophene for Selective Production of CH4

In today's society, mankind is confronted with two major problems: the energy crisis and the greenhouse effect. The artificial photosynthesis can use solar energy to convert greenhouse gas CO2 into high-value compounds, which is an ideal solution to alleviate the energy crisis and solve the problem of global warming. The combination of ZnO and polythiophenes (PTh) can make up for each other's drawbacks, thus improving the photoresponse behavior and separation efficiency of photogenerated carriers. PTh layer can transfer photogenerated electrons to ZnO, thereby extending the lifetime of photogenerated charges. The production rate of CH4 from photoreduction of CO2 with ZnO/PTh10 is 4.3 times that of pure ZnO, and the selectivity of CH4 is increased from 70.2% to 92.2%. The conductive PTh can absorb photons to induce π–π* transition, the photogenerated electrons can transfer from LUMO to the conduction band (CB) of ZnO, thus more electrons involve in the reduction of CO2.