Abiotic oxygen formation predates photosynthesis,sustaining early chemical evolution,yet its elementary mechanisms remain contested.Here,we show the production pathways for molecular oxygen from doubly ionized carbon ...Abiotic oxygen formation predates photosynthesis,sustaining early chemical evolution,yet its elementary mechanisms remain contested.Here,we show the production pathways for molecular oxygen from doubly ionized carbon dioxide upon electron-impact.Through fragment ions and electron coincidence momentum imaging,we unambiguously determine the ionization mechanism by measuring the projectile energy loss in association with the C^(+) +O_(2)^(+) channel.Further potential energy and trajectory calculations enable us to elucidate the dynamical details of this fragmentation process,in which a bond rearrangement pathway is found to proceed via the structural deformation to a triangular intermediate.Moreover,we demonstrate a further roaming pathway for the formation of O_(2)^(+) from CO_(2)^(+) 2,in which a frustrated C-O bond cleavage leaves the O atom without sufficient energy to escape.The O atom then wanders around varied configuration spaces of the flat potential energy regions and forms a C-O-O_(2)^(+) intermediate prior to the final products C^(+) +O_(2)^(+).Considering the large quantities of free electrons in interstellar space,the processes revealed here are expected to be significant and should be incorporated into atmospheric evolution models.展开更多
Acidic electrochemical CO_(2) reduction(CO_(2) RR)mitigates CO_(2) loss and energy inefficiencies but suffers from limited selectivity.Insufficient understanding of the interfacial microenvironment and cation specific...Acidic electrochemical CO_(2) reduction(CO_(2) RR)mitigates CO_(2) loss and energy inefficiencies but suffers from limited selectivity.Insufficient understanding of the interfacial microenvironment and cation specificity hinders the development of efficient interfacial design methods.Here,we integrate ab initio-derived reaction kinetics with mass transfer modeling into a multiscale framework that reproduces the bell-shaped Faradaic efficiency profile inaccessible to the Butler-Volmer equations.Our results emphasize the role of hydrogen bonding in CO_(2) activation and reveal a potential-dependent shift in the rate-determining steps.We also demonstrate that cations inhibit competing hydrogen evolution by strengthening the interfacial electric field and disrupting the hydrogen-bond network.However,their accumulation near the outer Helmholtz plane induces strong steric effects,impeding CO_(2) supply.Furthermore,the parametric analysis highlights the critical role of strategies such as pressurization and pore-confined electrolyte control in overcoming interfacial CO_(2) transport limitations,enhancing selectivity,and broadening the operating potential window.This work advances a multiscale perspective on interfacial mass transfer and cation effects,establishing a unified framework for reaction interface design in acidic CO_(2) RR.展开更多
An upconversion nanoparticle(NaErF_(4)∶Yb/Tm@NaLuF_(4)∶Yb@NaLuF_(4)∶Nd/Yb@NaLuF_(4),noted as UC)was designed,emitting strong red light by 808 nm laser.The mesoporous silica(mSiO_(2))shell co‑doped with chlorin e6(C...An upconversion nanoparticle(NaErF_(4)∶Yb/Tm@NaLuF_(4)∶Yb@NaLuF_(4)∶Nd/Yb@NaLuF_(4),noted as UC)was designed,emitting strong red light by 808 nm laser.The mesoporous silica(mSiO_(2))shell co‑doped with chlorin e6(Ce6)and triethoxy(1H,1H,2H,2H‑nonafluorohexyl)silane(TFS)was coated on the outer layer of UC,and then a layer of HKUST‑1 shell was coated.The obtained nanocomposite UC@Ce6/TFS@mSiO_(2)@HKUST‑1(noted as UCTSH)was used for the synergistic treatment of chemodynamic therapy(CDT)and photodynamic therapy(PDT).Interestingly,the nanostructures can specifically re lease Cu^(2+)in the acidic tumor microenvironment.Cu^(2+)reacts with excess hydrogen peroxide(H_(2)O_(2))in the tumor microenvironment to form cytotoxic hydroxyl radical.Secondly,Ce6,with the action of oxygen‑carrying TFS,selectively produces a large amount of singlet oxygen by 808 nm laser irradiation.UCTSH can enhance the anti‑tumor effects of PDT and CDT by increasing the production level of reactive oxygen species,without causing damage to normal cells.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.12325406,92261201,12404305,and W2512072)the Shaanxi Province Natural Science Fundamental Research Project (Grant Nos.2023JC-XJ-03 and23JSQ013)the China Postdoctoral Science Foundation (Grant Nos.BX20240286 and 2024M7625)。
文摘Abiotic oxygen formation predates photosynthesis,sustaining early chemical evolution,yet its elementary mechanisms remain contested.Here,we show the production pathways for molecular oxygen from doubly ionized carbon dioxide upon electron-impact.Through fragment ions and electron coincidence momentum imaging,we unambiguously determine the ionization mechanism by measuring the projectile energy loss in association with the C^(+) +O_(2)^(+) channel.Further potential energy and trajectory calculations enable us to elucidate the dynamical details of this fragmentation process,in which a bond rearrangement pathway is found to proceed via the structural deformation to a triangular intermediate.Moreover,we demonstrate a further roaming pathway for the formation of O_(2)^(+) from CO_(2)^(+) 2,in which a frustrated C-O bond cleavage leaves the O atom without sufficient energy to escape.The O atom then wanders around varied configuration spaces of the flat potential energy regions and forms a C-O-O_(2)^(+) intermediate prior to the final products C^(+) +O_(2)^(+).Considering the large quantities of free electrons in interstellar space,the processes revealed here are expected to be significant and should be incorporated into atmospheric evolution models.
基金supported by the National Natural Science Foundation of China(52394202 and 52476056)key project of the Joint Fund for Innovation and Development of Chongqing Natural Science Foundation(CSTB2022NSCQ-LZX0013)+1 种基金the Innovative Research Group Project of the National Natural Science Foundation of China(52021004)the Natural Science Foundation of Chongqing,China(CSTB2024NSCQ-MSX0915).
文摘Acidic electrochemical CO_(2) reduction(CO_(2) RR)mitigates CO_(2) loss and energy inefficiencies but suffers from limited selectivity.Insufficient understanding of the interfacial microenvironment and cation specificity hinders the development of efficient interfacial design methods.Here,we integrate ab initio-derived reaction kinetics with mass transfer modeling into a multiscale framework that reproduces the bell-shaped Faradaic efficiency profile inaccessible to the Butler-Volmer equations.Our results emphasize the role of hydrogen bonding in CO_(2) activation and reveal a potential-dependent shift in the rate-determining steps.We also demonstrate that cations inhibit competing hydrogen evolution by strengthening the interfacial electric field and disrupting the hydrogen-bond network.However,their accumulation near the outer Helmholtz plane induces strong steric effects,impeding CO_(2) supply.Furthermore,the parametric analysis highlights the critical role of strategies such as pressurization and pore-confined electrolyte control in overcoming interfacial CO_(2) transport limitations,enhancing selectivity,and broadening the operating potential window.This work advances a multiscale perspective on interfacial mass transfer and cation effects,establishing a unified framework for reaction interface design in acidic CO_(2) RR.
文摘An upconversion nanoparticle(NaErF_(4)∶Yb/Tm@NaLuF_(4)∶Yb@NaLuF_(4)∶Nd/Yb@NaLuF_(4),noted as UC)was designed,emitting strong red light by 808 nm laser.The mesoporous silica(mSiO_(2))shell co‑doped with chlorin e6(Ce6)and triethoxy(1H,1H,2H,2H‑nonafluorohexyl)silane(TFS)was coated on the outer layer of UC,and then a layer of HKUST‑1 shell was coated.The obtained nanocomposite UC@Ce6/TFS@mSiO_(2)@HKUST‑1(noted as UCTSH)was used for the synergistic treatment of chemodynamic therapy(CDT)and photodynamic therapy(PDT).Interestingly,the nanostructures can specifically re lease Cu^(2+)in the acidic tumor microenvironment.Cu^(2+)reacts with excess hydrogen peroxide(H_(2)O_(2))in the tumor microenvironment to form cytotoxic hydroxyl radical.Secondly,Ce6,with the action of oxygen‑carrying TFS,selectively produces a large amount of singlet oxygen by 808 nm laser irradiation.UCTSH can enhance the anti‑tumor effects of PDT and CDT by increasing the production level of reactive oxygen species,without causing damage to normal cells.
