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
Novel methanol-tolerant oxygen-reduction catalysts, iridium-sulphur （Ir-S） chalcogenides with different Ir/S atomic ratios, were synthesized via a precipitation method using H2IrCI6 and Na2SO3 as the Ir and S precur...Novel methanol-tolerant oxygen-reduction catalysts, iridium-sulphur （Ir-S） chalcogenides with different Ir/S atomic ratios, were synthesized via a precipitation method using H2IrCI6 and Na2SO3 as the Ir and S precursors. Powder X-ray diffraction （XRD） and transmission electron microscopy （TEM） were used to characterize the lrxSl_x/C chalcogenide catalysts. Particle size ranging from 2.5 to 2.8 nm though obvi- ous agglomeration was found on carbon support. However, these chalcogenide catalysts showed strong catalytic activity towards the oxygen reduction reaction （ORR） and high methanol tolerance, strongly suggesting these novel catalysts as promising candidates for direct methanol fuel cell （DMFC） cathode applications.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.
基金the National High Technology R&D Program of China (2007AA05Z146,2007AA05Z150)Natural Science Foundation of China
文摘Novel methanol-tolerant oxygen-reduction catalysts, iridium-sulphur （Ir-S） chalcogenides with different Ir/S atomic ratios, were synthesized via a precipitation method using H2IrCI6 and Na2SO3 as the Ir and S precursors. Powder X-ray diffraction （XRD） and transmission electron microscopy （TEM） were used to characterize the lrxSl_x/C chalcogenide catalysts. Particle size ranging from 2.5 to 2.8 nm though obvi- ous agglomeration was found on carbon support. However, these chalcogenide catalysts showed strong catalytic activity towards the oxygen reduction reaction （ORR） and high methanol tolerance, strongly suggesting these novel catalysts as promising candidates for direct methanol fuel cell （DMFC） cathode applications.
