Figure 15.

a) SEM image of CoO _x nanosheets supported on Cu foam. b) Schematic illustration of photoelectrochemical CO₂ conversion system by using CoO _x nanosheets/Cu foam as photocathode and TNTs as photoanode. c) Photoelectrochemical and electrochemical CO₂ conversion performances of CoO _x nanosheets/Cu foam. Reproduced with permission.^{[ 128 ]} Copyright 2020, Elsevier B.V. d) LSV curves of Ag/WO₃‐NR with different amounts of Ag in photoelectrochemical and electrochemical CO₂ conversion, respectively. e) Schematic of the possible reaction mechanism of photoelectrocatalytic CO₂‐to‐formate conversion by using Ag/WO₃‐NR catalyst. Reproduced with permission.^{[ 130 ]} Copyright 2020, Elsevier Ltd. f) Product yield and g) TON tendency of formic acid formation under different potentials of photoelectrochemical CO₂ conversion with Co porphyrin/g‐C₃N₄ catalyst. h) The proposed charges transfer pathway of Co porphyrin/g‐C₃N₄ catalyst toward CO₂RR. Reproduced with permission.^{[ 131 ]} Copyright 2017, The Royal Society of Chemistry.