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
Ammonia(NH3)is the second-most-produced chemical worldwide and has numerous industrial applications.However,such applications pose significant risks,as evidenced by human casualties caused by NH_(3) leaks or poisoning...Ammonia(NH3)is the second-most-produced chemical worldwide and has numerous industrial applications.However,such applications pose significant risks,as evidenced by human casualties caused by NH_(3) leaks or poisoning in confined environments.This highlights the critical need for highly portable and intuitive wearable NH_(3) sensors.The chemiresistive sensors are widely employed in wearable devices due to their simple structure,high sensitivity,and short response times,but are prone to malfunctioning and inaccurate gas detection because of the corrosion or failure of the sensing material under the influence of humidity,high temperatures,and interfering gas species.Addressing these limitations,a gas-sensing platform with a polymer-based nanofiber structure has been developed,providing flexibility and facilitating efficient transport of NH_(3) between the colorimetric(bromocresol-green-based)and chemiresistive(poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)-based)sensing layers.This dual-mode design enables reliable NH_(3) detection.The NH_(3)-sensing performance of each individual layer is comparable to that of the dual-mode gas-sensing platform,which operates effectively even when attached to human skin and in humid environments.Therefore,this study establishes a robust,selective,and reproducible NH3 sensor for diverse applications and introduces an innovative sensor engineering paradigm.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supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(RS-2024-00412335)supported by the Korea Institute of Marine Science and Technology Promotion(KIMST),funded by the Ministry of Oceans and Fisheries(RS-2022-KS221606).
文摘Ammonia(NH3)is the second-most-produced chemical worldwide and has numerous industrial applications.However,such applications pose significant risks,as evidenced by human casualties caused by NH_(3) leaks or poisoning in confined environments.This highlights the critical need for highly portable and intuitive wearable NH_(3) sensors.The chemiresistive sensors are widely employed in wearable devices due to their simple structure,high sensitivity,and short response times,but are prone to malfunctioning and inaccurate gas detection because of the corrosion or failure of the sensing material under the influence of humidity,high temperatures,and interfering gas species.Addressing these limitations,a gas-sensing platform with a polymer-based nanofiber structure has been developed,providing flexibility and facilitating efficient transport of NH_(3) between the colorimetric(bromocresol-green-based)and chemiresistive(poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)-based)sensing layers.This dual-mode design enables reliable NH_(3) detection.The NH_(3)-sensing performance of each individual layer is comparable to that of the dual-mode gas-sensing platform,which operates effectively even when attached to human skin and in humid environments.Therefore,this study establishes a robust,selective,and reproducible NH3 sensor for diverse applications and introduces an innovative sensor engineering paradigm.
