Pulsed electrolysis for CO_(2)reduction reaction has emerged as an effective method to enhance catalyst efficiency and optimize product selectivity.However,challenges remain in understanding the mechanisms of surface ...Pulsed electrolysis for CO_(2)reduction reaction has emerged as an effective method to enhance catalyst efficiency and optimize product selectivity.However,challenges remain in understanding the mechanisms of surface transformation under pulsed conditions.In this study,using in-situ time-resolved surface-enhanced Raman spectroscopy and differential electrochemical mass spectroscopy,we found local pH at the surface and Cu–O–C species that was generated during the anodic pulse played a key role in pulsed electrolysis.During the pulsed oxidation,an oxidation layer first formed,depleting OH–and lowering the local pH.When the pH was below 8.4,HCO_(3)–transformed the oxidation layer to a nanometer-thick Cu–O–C species,which is a highly reactive catalyst.In the reduction pulse,about 7.4%of the surface Cu–O–C was transformed into CO and CuOx species,enhancing CO_(2)reduction activity.Even in Ar-saturated 0.1 M KHCO_(3),through a Cu–O–C intermediate,a Faradaic efficiency of 0.17%for bicarbonate reduction to CO was observed.Our findings highlight the crucial role of the anodic pulse process in improving CO_(2)reduction activity.展开更多
Electrocatalytic CO2 reduction (ECR) into value-added chemicals offers potential solution for renewable energy as well as global carbon footprint concerns. In this review we introduce the general methods and metrics t...Electrocatalytic CO2 reduction (ECR) into value-added chemicals offers potential solution for renewable energy as well as global carbon footprint concerns. In this review we introduce the general methods and metrics that are commonly applied in ECR, followed by a discussion of current reaction mechanisms and different pathways. We highlight how size and structure of electrocatalysts affect ECR performance and review recent advances in metalfree and single-atom catalysts. The challenges of ECR are also discussed and optimistic perspectives are made for future work.展开更多
The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely un...The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely unknown. Shikimic acid (ShA) pathway is a main metabolic pathway closely related to the synthesis of hormones and many important secondary metabolites participating in plant phase change. So,whether ShA regulates phase change in plants is worth clarifying. Here, the distinct morphological characteristics and the underlying mechanisms of phase change in jujube (Ziziphus jujuba Mill.), an important fruit tree native to China with nutritious fruit and outstanding tolerance abiotic stresses, were clarified. A combined transcriptome and metabolome analysis found that ShA is positively involved in jujube(Yuhong’×Xing 16’) phase change. The genes in the upstream of ShA synthesis pathway (ZjDAHPS, ZjDHQS and ZjSDH), the contents of ShA and the downstream secondary metabolites like phenols were significantly upregulated in the phase change period. Further, the treatment of spraying exogenous ShA verified that ShA at a very low concentration (60 mg·L^(-1)) can substantially speed up the phase change and flowering of jujube and other tested plants including Arabidopsis, tomato and wheat. The exogenous ShA (60 mg·L^(-1)) treatment in jujube seedlings could increase the accumulation of endogenous ShA, enhance leaf photosynthesis and the synthesis of phenols especially flavonoids and phenolic acids, and promote the expression of genes (ZjCOs, ZjNFYs and ZjPHYs) involved in flowering pathway. Basing on above results, we put forward a propose for the underlying mechanism of ShA regulating phase change, and a hypothesis that ShA could be considered a phytohormone-like substance because it is endogenous, ubiquitous, movable and highly efficient at very low concentrations. This study highlights the critical role of ShA in plant phase change and its phytohormone-like properties.展开更多
The application of redox mediators has been considered as a promising strategy to boost the performance of aprotic Li-O_(2)batteries.However,the issues brought with redox mediators,especially on the Li anode side have...The application of redox mediators has been considered as a promising strategy to boost the performance of aprotic Li-O_(2)batteries.However,the issues brought with redox mediators,especially on the Li anode side have been overlooked.Here,we propose a facile approach of preparing a gel polymer membrane that not only allow uniform Li plating/stripping withlarge current densities over extended cycling but also inhibit the diffusion of redox mediators and avoid redox shuttling,self-discharge,and internal shortcircuiting.More importantly,the gel polymer membrane prevents the penetration of O_(2)and superoxide intermediates from the Li anode.Therefore,it ensures the successful application of both lithium anode and redox mediators in Li-O_(2)batteries to achieve the desired high capacity and rate performance.Meanwhile,it helps understand the benefit and problems of added redox mediators and reactive oxygen species so that theperformance of such Li-O_(2)batteries can be truly evaluated.展开更多
The solid electrolyte interphase(SEI)layer is crucial for lithium-ion batteries and has a significant impact on the electrochemical performance of negative electrodes,particularly for conversion-type materials with la...The solid electrolyte interphase(SEI)layer is crucial for lithium-ion batteries and has a significant impact on the electrochemical performance of negative electrodes,particularly for conversion-type materials with large volume changes and metallic lithium anode.However,the SEI layer has not yet been well understood.In this work,we used redox mediators of various sizes to probe the SEI layer that formed in carbonate-based electrolytes.The SEI layer has diffusion channels that allow the mediators smaller than benzoquinone(5.7Å)to pass,suggesting that lithium ions have to partially de-solvate to pass through.Additionally,due to partial desolvation,the diffusion coefficient in the diffusion channels was higher than that in the bulk electrolytes.Both lithium salts and solvents influenced the size and areal density of channels.Herein,we aim to enhance comprehension of SEI structure and provide a method to study porous SEI layers using mediators,which can be extended to other electrochemical systems.展开更多
基金financially supported by the National Natural Science Foundation of China (52173173, 22403047)Natural Science Foundation of Jiangsu Province (BK20220051)+2 种基金Jiangsu Province Carbon Peak and Neutrality Innovation Program (Industry tackling on prospect and key technology) (BE2022031-4, BE2022002-3)The Natural Foundation of Jiangsu Higher Education Institutions of China (23KJB430021)State Key Laboratory of Materials-Oriented Chemical Engineering (No.SKL-MCE-24A16)
文摘Pulsed electrolysis for CO_(2)reduction reaction has emerged as an effective method to enhance catalyst efficiency and optimize product selectivity.However,challenges remain in understanding the mechanisms of surface transformation under pulsed conditions.In this study,using in-situ time-resolved surface-enhanced Raman spectroscopy and differential electrochemical mass spectroscopy,we found local pH at the surface and Cu–O–C species that was generated during the anodic pulse played a key role in pulsed electrolysis.During the pulsed oxidation,an oxidation layer first formed,depleting OH–and lowering the local pH.When the pH was below 8.4,HCO_(3)–transformed the oxidation layer to a nanometer-thick Cu–O–C species,which is a highly reactive catalyst.In the reduction pulse,about 7.4%of the surface Cu–O–C was transformed into CO and CuOx species,enhancing CO_(2)reduction activity.Even in Ar-saturated 0.1 M KHCO_(3),through a Cu–O–C intermediate,a Faradaic efficiency of 0.17%for bicarbonate reduction to CO was observed.Our findings highlight the crucial role of the anodic pulse process in improving CO_(2)reduction activity.
基金National Natural Science Foundation of China (Grant No. 51773092)National Natural Science Foundation of China (21825202, 21575135, 21733012, 21633008, 21605136)+3 种基金Research Fundation of State Key Lab (ZK201717)the support from Department of Education of Jilin Province (JJKH20190767KJ)Department of Education of Guangdong Province (2017KCXTD031)Science Foundation for High-level Talents of Wuyi University (2017RC23)
文摘Electrocatalytic CO2 reduction (ECR) into value-added chemicals offers potential solution for renewable energy as well as global carbon footprint concerns. In this review we introduce the general methods and metrics that are commonly applied in ECR, followed by a discussion of current reaction mechanisms and different pathways. We highlight how size and structure of electrocatalysts affect ECR performance and review recent advances in metalfree and single-atom catalysts. The challenges of ECR are also discussed and optimistic perspectives are made for future work.
基金partially supported by the National Natural Science Foundation of China (Grant No.31772285)the National Key R&D Program Project Funding (Grant No.2018YFD1000607)Foundation for 100 Innovative Talents of Hebei Province(Grant No.SLRC2019031)。
文摘The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely unknown. Shikimic acid (ShA) pathway is a main metabolic pathway closely related to the synthesis of hormones and many important secondary metabolites participating in plant phase change. So,whether ShA regulates phase change in plants is worth clarifying. Here, the distinct morphological characteristics and the underlying mechanisms of phase change in jujube (Ziziphus jujuba Mill.), an important fruit tree native to China with nutritious fruit and outstanding tolerance abiotic stresses, were clarified. A combined transcriptome and metabolome analysis found that ShA is positively involved in jujube(Yuhong’×Xing 16’) phase change. The genes in the upstream of ShA synthesis pathway (ZjDAHPS, ZjDHQS and ZjSDH), the contents of ShA and the downstream secondary metabolites like phenols were significantly upregulated in the phase change period. Further, the treatment of spraying exogenous ShA verified that ShA at a very low concentration (60 mg·L^(-1)) can substantially speed up the phase change and flowering of jujube and other tested plants including Arabidopsis, tomato and wheat. The exogenous ShA (60 mg·L^(-1)) treatment in jujube seedlings could increase the accumulation of endogenous ShA, enhance leaf photosynthesis and the synthesis of phenols especially flavonoids and phenolic acids, and promote the expression of genes (ZjCOs, ZjNFYs and ZjPHYs) involved in flowering pathway. Basing on above results, we put forward a propose for the underlying mechanism of ShA regulating phase change, and a hypothesis that ShA could be considered a phytohormone-like substance because it is endogenous, ubiquitous, movable and highly efficient at very low concentrations. This study highlights the critical role of ShA in plant phase change and its phytohormone-like properties.
基金financially supported by the National Natural Science Foundation of China(51773092,21975124,22008117)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure(SKL201911SIC)+1 种基金Natural Science Project by Higher Education Institutions of Jiangsu Province(20KJB530009)the Research Foundation of State Key Lab(ZK201717)
文摘The application of redox mediators has been considered as a promising strategy to boost the performance of aprotic Li-O_(2)batteries.However,the issues brought with redox mediators,especially on the Li anode side have been overlooked.Here,we propose a facile approach of preparing a gel polymer membrane that not only allow uniform Li plating/stripping withlarge current densities over extended cycling but also inhibit the diffusion of redox mediators and avoid redox shuttling,self-discharge,and internal shortcircuiting.More importantly,the gel polymer membrane prevents the penetration of O_(2)and superoxide intermediates from the Li anode.Therefore,it ensures the successful application of both lithium anode and redox mediators in Li-O_(2)batteries to achieve the desired high capacity and rate performance.Meanwhile,it helps understand the benefit and problems of added redox mediators and reactive oxygen species so that theperformance of such Li-O_(2)batteries can be truly evaluated.
基金financially supported by the Jiangsu Province Carbon Peak and Neutrality Innovation Program(Industry tackling on prospect and key technology)(BE2022002-3,BE2022031-4)National Natural Science Foundation of China(52173173)+1 种基金Natural Science Foundation of Jiangsu Province(BK20220051)Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX24_0545).
文摘The solid electrolyte interphase(SEI)layer is crucial for lithium-ion batteries and has a significant impact on the electrochemical performance of negative electrodes,particularly for conversion-type materials with large volume changes and metallic lithium anode.However,the SEI layer has not yet been well understood.In this work,we used redox mediators of various sizes to probe the SEI layer that formed in carbonate-based electrolytes.The SEI layer has diffusion channels that allow the mediators smaller than benzoquinone(5.7Å)to pass,suggesting that lithium ions have to partially de-solvate to pass through.Additionally,due to partial desolvation,the diffusion coefficient in the diffusion channels was higher than that in the bulk electrolytes.Both lithium salts and solvents influenced the size and areal density of channels.Herein,we aim to enhance comprehension of SEI structure and provide a method to study porous SEI layers using mediators,which can be extended to other electrochemical systems.
