Selectivity Modulation of Organic Semiconductor Electrophotocatalysis Enables Highly Selective CO2-to-Methanol Conversion

Poor efficiency and selectivity have severely hindered the application of CO2 reduction into fuels for achieving carbon neutrality through sustainable energy sources, such as solar light and derived electricity. Herein, we report splendid product selectivity control of CO2RR by newly developed organic-semiconductor-rGO cathode film (PDPP/rGO), which can effectively regulate the production of CO, CO/H2, acetone and methanol by photocatalysis (PC), elecrtrocatalysis (EC) and electrophotocatalysis (EPC), respectively. Strikingly, EPC CO2RR produces methanol with nearly 100% selectivity and high Faraday efficiency (> 60%) under an ultralow cell voltage of -0.16 VRHE and visible-light irradiation (λ > 400 nm) without any sacrificial agent and metal assistance. EPCs promoted ultralow reductive potential (-2.37 VRHE, < -1.9 VRHE for CO2/CO2•-), ensuring continuous production of CO2•-. In-situ IR spectra and theoretical simulation revealed that the hydrogen-bonding interaction allowed better complex structure between carbon-oxygen intermediates and amide group in PDPP strengthening the multiple electron transfer and proton addition to reductive intermediates. This dual catalysis- and composition-based selectivity control for CO2RR into liquid fuels demonstrates the forefront of catalytic selectivity and reductive potential control by organic semiconductors.