Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strateg...Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strategy for the functionalization and conversion of C-H bonds of 1,4-naphthoquinones into C-N bonds,providing an effective route to synthesize 2-(N-substituted amino)-1,4-naphthoquinone with high yield under mild conditions.Additionally,the synergistic catalytic mechanism was investigated by 1H NMR titration experiments and LC-MS analysis,with experimental results sufficiently and consistently supporting the proposed mechanism of the catalytic cycle.展开更多
The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMC...The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO_(2).These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO_(2) resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.展开更多
The development of high-energy-density Li-ion batteries is hindered by the irreversible capacity loss during the initial charge-discharge process.Therefore,pre-lithiation technology has emerged in the past few decades...The development of high-energy-density Li-ion batteries is hindered by the irreversible capacity loss during the initial charge-discharge process.Therefore,pre-lithiation technology has emerged in the past few decades as a powerful method to supplement the undesired lithium loss,thereby maximizing the energy utilization of LIBs and extending their cycle life.Lithium oxalate(Li_(2)C_(2)O_(4)),with a high lithium content and excellent air stability,has been considered one of the most promising materials for lithium compensation.However,the sluggish electrochemical decomposition kinetics of the material severely hinders its further commercial application.Here,we introduce a recrystallization strategy combined with atomic Ni catalysts to modulate the mass transport and decomposition reaction kinetics.The decomposition potential of Li_(2)C_(2)O_(4)is significantly decreased from~4.90V to~4.30V with a high compatibility with the current battery systems.In compared to the bare NCM//Li cell,the Ni/N-rGO and Li_(2)C_(2)O_(4)composite(Ni-LCO)modified cell releases an extra capacity of~11.7%.Moreover,this ratio can be magnified in the NCM//SiOx full cell,resulting in a 30.4%higher reversible capacity.Overall,this work brings the catalytic paradigm into the pre-lithiation technology,which opens another window for the development of high-energy-density battery systems.展开更多
基金2024 Special Talent Introduction Projects of Key R&D Program of Ningxia Hui Autonomous Region(2024BEH04049)the 2024 Guyuan City Innovation-Driven Achievement Transformation Project(2024BGTYF01-47)2025 Ningxia Natural Science Foundation Program(2025AAC030624).
文摘Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strategy for the functionalization and conversion of C-H bonds of 1,4-naphthoquinones into C-N bonds,providing an effective route to synthesize 2-(N-substituted amino)-1,4-naphthoquinone with high yield under mild conditions.Additionally,the synergistic catalytic mechanism was investigated by 1H NMR titration experiments and LC-MS analysis,with experimental results sufficiently and consistently supporting the proposed mechanism of the catalytic cycle.
文摘The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO_(2).These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO_(2) resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.
基金supported by National Natural Science Foundation of China(Grant No.52002094)Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515110756)+2 种基金Shenzhen Science and Technology Program(Grant No.JCYJ20210324121411031,JSGG202108021253804014,RCBS20210706092218040)the Shenzhen Steady Support Plan(GXWD20221030205923001,GXWD20201230155427003-20200824103000001)School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(Grant No.DD29100027,DD45001022).
文摘The development of high-energy-density Li-ion batteries is hindered by the irreversible capacity loss during the initial charge-discharge process.Therefore,pre-lithiation technology has emerged in the past few decades as a powerful method to supplement the undesired lithium loss,thereby maximizing the energy utilization of LIBs and extending their cycle life.Lithium oxalate(Li_(2)C_(2)O_(4)),with a high lithium content and excellent air stability,has been considered one of the most promising materials for lithium compensation.However,the sluggish electrochemical decomposition kinetics of the material severely hinders its further commercial application.Here,we introduce a recrystallization strategy combined with atomic Ni catalysts to modulate the mass transport and decomposition reaction kinetics.The decomposition potential of Li_(2)C_(2)O_(4)is significantly decreased from~4.90V to~4.30V with a high compatibility with the current battery systems.In compared to the bare NCM//Li cell,the Ni/N-rGO and Li_(2)C_(2)O_(4)composite(Ni-LCO)modified cell releases an extra capacity of~11.7%.Moreover,this ratio can be magnified in the NCM//SiOx full cell,resulting in a 30.4%higher reversible capacity.Overall,this work brings the catalytic paradigm into the pre-lithiation technology,which opens another window for the development of high-energy-density battery systems.
