In this paper, we report photoelectrochemical（PEC） conversion of carbon dioxide（CO_2） using photocathodes based on Cu_2O nanowires（NWs） overcoated with Cu~＋-incorporated crystalline TiO_2（TiO_2–Cu~＋ ）shell....In this paper, we report photoelectrochemical（PEC） conversion of carbon dioxide（CO_2） using photocathodes based on Cu_2O nanowires（NWs） overcoated with Cu~＋-incorporated crystalline TiO_2（TiO_2–Cu~＋ ）shell. Cu_2O NW photocathodes show remanent photocurrent of 5.3% after 30 min of PEC reduction of CO_2.After coating Cu_2O with TiO_2–Cu~＋ overlayer, the remanent photocurrent is 27.6%, which is an increase by5.2 fold. The charge transfer resistance of Cu_2O/TiO_2–Cu~＋ is 0.423 k/cm2, whereas Cu_2O photocathode shows resistivity of 0.781 k/cm2 under irradiation. Mott–Schottky analysis reveals that Cu~＋ species embedded in TiO_2 layer is responsible for enhanced adsorption of CO_2 on TiO_2 surface, as evidenced by the decrease of capacitance in the Helmholtz layer. On account of these electrochemical and electronic effects by the Cu~＋ species, the Faradaic efficiency（FE） of photocathodes reaches as high as 56.5% when TiO_2–Cu~＋ is added to Cu_2O, showing drastic increase from 23.6% by bare Cu_2O photocathodes.展开更多
基金supported by the National Research Foundation (NRF) grants funded by the Korean government (no.NRF-20110030256, NRF-2017R1A2B2011066 and NRF-2016M3A7B4910618)funded by the Saudi Aramco-KAIST CO2 Management Center
文摘In this paper, we report photoelectrochemical（PEC） conversion of carbon dioxide（CO_2） using photocathodes based on Cu_2O nanowires（NWs） overcoated with Cu~＋-incorporated crystalline TiO_2（TiO_2–Cu~＋ ）shell. Cu_2O NW photocathodes show remanent photocurrent of 5.3% after 30 min of PEC reduction of CO_2.After coating Cu_2O with TiO_2–Cu~＋ overlayer, the remanent photocurrent is 27.6%, which is an increase by5.2 fold. The charge transfer resistance of Cu_2O/TiO_2–Cu~＋ is 0.423 k/cm2, whereas Cu_2O photocathode shows resistivity of 0.781 k/cm2 under irradiation. Mott–Schottky analysis reveals that Cu~＋ species embedded in TiO_2 layer is responsible for enhanced adsorption of CO_2 on TiO_2 surface, as evidenced by the decrease of capacitance in the Helmholtz layer. On account of these electrochemical and electronic effects by the Cu~＋ species, the Faradaic efficiency（FE） of photocathodes reaches as high as 56.5% when TiO_2–Cu~＋ is added to Cu_2O, showing drastic increase from 23.6% by bare Cu_2O photocathodes.
