Solar-driven carbon dioxide reduction reaction(CO_(2)RR)provides an oppor tunity to produce value-added chemical feedstocks and fuels.However,achieving efficient and stable photoelectrochemical(PEC)CO_(2)RR into selec...Solar-driven carbon dioxide reduction reaction(CO_(2)RR)provides an oppor tunity to produce value-added chemical feedstocks and fuels.However,achieving efficient and stable photoelectrochemical(PEC)CO_(2)RR into selec tive products is challenging owing to the difficulties associated with the optical and the electrical configuration of PEC devices and electrocatalyst properties.Herein,we construct an efficient,concentrated sunlight-driven CO_(2)RR setup consisting of InGaP/GaAs/Ge triple-junction cell as a photoanode and oxide-derived Au(Ox-Au)as a cathode to perform the unassisted PEC CO_(2)RR.Under one-sun illumination,a maximum operating current density of 11.5 mA cm^(-2) with an impressive Faradaic efficiency(FE)of~98%is achieved for carbon monoxide(CO)production,leading to a solar-to-fuel conversion efficiency of~15%.Under concentrated intensity of 10 sun,the photoanode records a maximum current density of~124 mAcm^(-2) and maintains~60%of FE for CO production.The results demonstrate crucial advancements in usingⅢ-Ⅴbased photoanodes for concentrated PEC CO_(2)RR.展开更多
This study presents a geochemical investigation of Tikak Parbat and Tipam Sandstone Formations occurring in and around Dilli area, Sivasagar, Assam. Petrographically Tikak Parbat and Tipam sandstones are mainly quartz...This study presents a geochemical investigation of Tikak Parbat and Tipam Sandstone Formations occurring in and around Dilli area, Sivasagar, Assam. Petrographically Tikak Parbat and Tipam sandstones are mainly quartzose arenite to sublitharenite types with their constituents being derived from recycled orogen provenance under sub-humid to humid climatic conditions. Geochemically, sandstones of both the formations range from sublitharenite to wacke. They indicate a recycled orogen source and influence of humid to arid condition. Source rocks of Tikak Parbat sandstones were more weathered than the Tipam sandstones. While Tikak Parbat sandstones show affinity towards passive margin, Tipam sandstones hint at active continental margin setup, where clasts were supplied from uplifted areas. Upliftment of provenance covering areas of Naga Patkai Range in the south east and Eastern Himalayas along the syntaxial bend during mid Miocene affected the sandstones. Tikak Parbat sandstones reflect a stable tectonic setup which later underwent a phase of volatility leading to deposition of the Tipam sandstones. Our study supports a sediment supply from the upper continental crust, largely of granitic composition, however, with a significant variation in their depth of source supply. Trace element analyses indicate depositional setup with low ventilation marked by both oxic and anoxic phases.展开更多
基金supported by the City University of Hong Kong(9380107 and 7005943)King Abdullah University of Science and Technology,and Agency for Science,Technology and Research(C230415018 and C231218003).
文摘Solar-driven carbon dioxide reduction reaction(CO_(2)RR)provides an oppor tunity to produce value-added chemical feedstocks and fuels.However,achieving efficient and stable photoelectrochemical(PEC)CO_(2)RR into selec tive products is challenging owing to the difficulties associated with the optical and the electrical configuration of PEC devices and electrocatalyst properties.Herein,we construct an efficient,concentrated sunlight-driven CO_(2)RR setup consisting of InGaP/GaAs/Ge triple-junction cell as a photoanode and oxide-derived Au(Ox-Au)as a cathode to perform the unassisted PEC CO_(2)RR.Under one-sun illumination,a maximum operating current density of 11.5 mA cm^(-2) with an impressive Faradaic efficiency(FE)of~98%is achieved for carbon monoxide(CO)production,leading to a solar-to-fuel conversion efficiency of~15%.Under concentrated intensity of 10 sun,the photoanode records a maximum current density of~124 mAcm^(-2) and maintains~60%of FE for CO production.The results demonstrate crucial advancements in usingⅢ-Ⅴbased photoanodes for concentrated PEC CO_(2)RR.
文摘This study presents a geochemical investigation of Tikak Parbat and Tipam Sandstone Formations occurring in and around Dilli area, Sivasagar, Assam. Petrographically Tikak Parbat and Tipam sandstones are mainly quartzose arenite to sublitharenite types with their constituents being derived from recycled orogen provenance under sub-humid to humid climatic conditions. Geochemically, sandstones of both the formations range from sublitharenite to wacke. They indicate a recycled orogen source and influence of humid to arid condition. Source rocks of Tikak Parbat sandstones were more weathered than the Tipam sandstones. While Tikak Parbat sandstones show affinity towards passive margin, Tipam sandstones hint at active continental margin setup, where clasts were supplied from uplifted areas. Upliftment of provenance covering areas of Naga Patkai Range in the south east and Eastern Himalayas along the syntaxial bend during mid Miocene affected the sandstones. Tikak Parbat sandstones reflect a stable tectonic setup which later underwent a phase of volatility leading to deposition of the Tipam sandstones. Our study supports a sediment supply from the upper continental crust, largely of granitic composition, however, with a significant variation in their depth of source supply. Trace element analyses indicate depositional setup with low ventilation marked by both oxic and anoxic phases.
