The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportio...The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.展开更多
Paired electrolysis of waste feedstocks holds an energy-efficient alternative for chemical production;however,the sluggish anodic oxidation limited the total efficiency under larger current density.Herein,we construct...Paired electrolysis of waste feedstocks holds an energy-efficient alternative for chemical production;however,the sluggish anodic oxidation limited the total efficiency under larger current density.Herein,we constructed ultralow-coordinated Ni species with Ni–O coordination number of∼3 via a hydrothermal synthesis-sulfidation-annealing process and electrochemical activation and demonstrated the vital role in accelerating the proton deintercalation and reactive oxygen intermediate·OH formation during electro-reforming polyethylene terephthalate hydrolysate(POR).The target catalyst NiCoSx/NF afforded a high formate productivity of 7.4 mmol cm^(−2)h^(−1)at∼600 mA cm^(−2)with a formate Faradic efficiency(FE_(formate))of 92.4%in POR and maintained a FE_(formate)of∼90%for 100 h at 2 A in a membrane electrode assembly electrolyzer.Coupling POR on NiCoSx/NF with carbon dioxide reduction reaction on oxygen vacancies enriched Vo-BiSnO reached effective concurrent formate production with 172.7%of FE_(formate)at 500 mA cm^(−2)and long-term stability.Such excellent performance shows the great prospect of electrocatalyst design by regulating the local metal environment.展开更多
Heteroatom-doped carbon materials have demonstrated great potential in the electrochemical reduction reaction of CO_(2)(CO_(2)RR)due to their versatile structure and function.However,rational structure control remains...Heteroatom-doped carbon materials have demonstrated great potential in the electrochemical reduction reaction of CO_(2)(CO_(2)RR)due to their versatile structure and function.However,rational structure control remains one challenge.In this work,we reported a unique carbon precursor of soft template-containing porous poly(ionic liquid)(PIL)that was directly synthesized via free-radical self-polymerization of ionic liquid monomer in a soft template route.Variation of the carbonization temperature in a direct pyrolysis process without any additive yielded a series of carbon materials with facile adjustable textural properties and N species.Significantly,the integration of soft-template in the PIL precursor led to the formation of hierarchical porous carbon material with a higher surface area and larger pore size than that from the template-free precursor.In CO_(2)RR to CO,the champion catalyst gave a Faraday efficiency of 83.0%and a current density of 1.79 mA·cm^(-2)at-0.9 V vs.reversible hydrogen electrode(vs.RHE).The abundant graphite N species and hierarchical pore structure,especially the unique hierarchical small-/ultramicropores were revealed to enable better CO_(2)RR performance.展开更多
Electrochemical CO_(2) reduction reaction(CO_(2) RR) has attracted growing attention in energy storage and sustainable production of fuels and chemicals. N-doped carbon materials are preferred metal-free electrocataly...Electrochemical CO_(2) reduction reaction(CO_(2) RR) has attracted growing attention in energy storage and sustainable production of fuels and chemicals. N-doped carbon materials are preferred metal-free electrocatalysts, but it remains one challenge to finely engineer the active sites and porosity. Herein, we demonstrated that ionic porous polyamides were a kind of versatile precursors to prepare functional carbon materials in a one-step pyrolysis process. The polyamide precursors allowed the maintenance of abundant N species at high temperatures. The existence of ionic moieties and large specific surface area of the precursors promoted the formation of larger porosity carbon with a large specific surface area and sufficient active graphitic-N species by controlling the pyrolysis temperature. The catalyst was highly selective in the CO_(2) RR to produce CO with a maximum Faraday efficiency above 99%, attributable to the improved mass transfer in a large porosity system. This work shows that ionic polyamides are promising carbon precursors for the fabrication of metal-free electrocatalysts for CO_(2) RR.展开更多
Evaluation of the river ecological environment can provide a basis for river management and ecological restoration.To conduct a comprehensive health assessment of the rivers in Tianjin,their biological,physical,and ch...Evaluation of the river ecological environment can provide a basis for river management and ecological restoration.To conduct a comprehensive health assessment of the rivers in Tianjin,their biological,physical,and chemical indicators are investigated on the basis of 32 river monitoring sites from August to September 2018.The comprehensive pollution and ecological integrity indexes of the rivers are analyzed.Results of the two evaluations,compared to achieve the river ecological environment evaluation,are as follows.1)Index of Ecological Integrity evaluation shows that among the sampling points,18.8%are"healthy",28.1%are"sub-healthy",40.6%are"fair",6.3%are"poor",and 6.3%are"very poor".2)The comprehensive evaluation of the chemical properties of the 32 river ecosystems in Tianjin shows severe overall river pollution and low standard water function area.Of the total sampling sites,16(50%)are heavily contaminated and 10(31.3%)are moderately contaminated.Excessive chemical oxygen demand and ammonia nitrogen are the main causes of water pollution.3)The Index of Ecological Integrity(IEI)has high correspondence with environmental factors.Pearson correlation analysis results show that the IEI index is significantly correlated with permanganate index(R=-0.453;P=0.023<0.05).Analysis results using BEST show that ammonia nitrogen is the best environmental parameter to explain the changes in IEI(R_(ho)=0.154;P=0.02<0.05)and those using RELATE show significant correlation between the biotic index and the environmental parameter matrices(R_(ho)=0.154;P=0.034<0.05).展开更多
基金National Natural Science Foundation of China(grants 22072065,22178162,and 22222806)Distinguished Youth Foundation of Jiangsu Province(grant BK20220053)Six talent peaks project in Jiangsu Province(grant JNHB-035)。
文摘The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.
基金We highly thank the funding from the National Natural Science Foundation of China(grants 22222806,22178162,22072065,and 22408170)the Distinguished Youth Foundation of Jiangsu Province(BK20220053)+2 种基金the National Key Research and Development Program of China(2024YFE0206900)the Six Talent Peaks Project in Jiangsu Province(grant JNHB-035)Agency for Science,Technology and Research(A*STAR)through Low Carbon Energy Research Finding Initiative(LCERFI01-0033|U2102d2006).
文摘Paired electrolysis of waste feedstocks holds an energy-efficient alternative for chemical production;however,the sluggish anodic oxidation limited the total efficiency under larger current density.Herein,we constructed ultralow-coordinated Ni species with Ni–O coordination number of∼3 via a hydrothermal synthesis-sulfidation-annealing process and electrochemical activation and demonstrated the vital role in accelerating the proton deintercalation and reactive oxygen intermediate·OH formation during electro-reforming polyethylene terephthalate hydrolysate(POR).The target catalyst NiCoSx/NF afforded a high formate productivity of 7.4 mmol cm^(−2)h^(−1)at∼600 mA cm^(−2)with a formate Faradic efficiency(FE_(formate))of 92.4%in POR and maintained a FE_(formate)of∼90%for 100 h at 2 A in a membrane electrode assembly electrolyzer.Coupling POR on NiCoSx/NF with carbon dioxide reduction reaction on oxygen vacancies enriched Vo-BiSnO reached effective concurrent formate production with 172.7%of FE_(formate)at 500 mA cm^(−2)and long-term stability.Such excellent performance shows the great prospect of electrocatalyst design by regulating the local metal environment.
基金support from the National Natural Science Foundation of China(Nos.22072065,U1662107,and 21476109)Six talent peaks project in Jiangsu Province(JNHB035)+3 种基金State Key Laboratory of Materials-Oriented Chemical Engineering(KL17-04)Jiangsu Provincial Science Foundation for Youths(SBK2020044703)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)High-Performance Computing Center of Nanjing Tech University。
文摘Heteroatom-doped carbon materials have demonstrated great potential in the electrochemical reduction reaction of CO_(2)(CO_(2)RR)due to their versatile structure and function.However,rational structure control remains one challenge.In this work,we reported a unique carbon precursor of soft template-containing porous poly(ionic liquid)(PIL)that was directly synthesized via free-radical self-polymerization of ionic liquid monomer in a soft template route.Variation of the carbonization temperature in a direct pyrolysis process without any additive yielded a series of carbon materials with facile adjustable textural properties and N species.Significantly,the integration of soft-template in the PIL precursor led to the formation of hierarchical porous carbon material with a higher surface area and larger pore size than that from the template-free precursor.In CO_(2)RR to CO,the champion catalyst gave a Faraday efficiency of 83.0%and a current density of 1.79 mA·cm^(-2)at-0.9 V vs.reversible hydrogen electrode(vs.RHE).The abundant graphite N species and hierarchical pore structure,especially the unique hierarchical small-/ultramicropores were revealed to enable better CO_(2)RR performance.
基金support from the National Natural Science Foundation of China ( 22072065, 22178162, U1662107, and 21476109)Six talent peaks project in Jiangsu Province (JNHB-035)+1 种基金State Key Laboratory of Materials-Oriented Chemical Engineering (KL18-09)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘Electrochemical CO_(2) reduction reaction(CO_(2) RR) has attracted growing attention in energy storage and sustainable production of fuels and chemicals. N-doped carbon materials are preferred metal-free electrocatalysts, but it remains one challenge to finely engineer the active sites and porosity. Herein, we demonstrated that ionic porous polyamides were a kind of versatile precursors to prepare functional carbon materials in a one-step pyrolysis process. The polyamide precursors allowed the maintenance of abundant N species at high temperatures. The existence of ionic moieties and large specific surface area of the precursors promoted the formation of larger porosity carbon with a large specific surface area and sufficient active graphitic-N species by controlling the pyrolysis temperature. The catalyst was highly selective in the CO_(2) RR to produce CO with a maximum Faraday efficiency above 99%, attributable to the improved mass transfer in a large porosity system. This work shows that ionic polyamides are promising carbon precursors for the fabrication of metal-free electrocatalysts for CO_(2) RR.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2018ZX07111002)the Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2017ZX07107001).
文摘Evaluation of the river ecological environment can provide a basis for river management and ecological restoration.To conduct a comprehensive health assessment of the rivers in Tianjin,their biological,physical,and chemical indicators are investigated on the basis of 32 river monitoring sites from August to September 2018.The comprehensive pollution and ecological integrity indexes of the rivers are analyzed.Results of the two evaluations,compared to achieve the river ecological environment evaluation,are as follows.1)Index of Ecological Integrity evaluation shows that among the sampling points,18.8%are"healthy",28.1%are"sub-healthy",40.6%are"fair",6.3%are"poor",and 6.3%are"very poor".2)The comprehensive evaluation of the chemical properties of the 32 river ecosystems in Tianjin shows severe overall river pollution and low standard water function area.Of the total sampling sites,16(50%)are heavily contaminated and 10(31.3%)are moderately contaminated.Excessive chemical oxygen demand and ammonia nitrogen are the main causes of water pollution.3)The Index of Ecological Integrity(IEI)has high correspondence with environmental factors.Pearson correlation analysis results show that the IEI index is significantly correlated with permanganate index(R=-0.453;P=0.023<0.05).Analysis results using BEST show that ammonia nitrogen is the best environmental parameter to explain the changes in IEI(R_(ho)=0.154;P=0.02<0.05)and those using RELATE show significant correlation between the biotic index and the environmental parameter matrices(R_(ho)=0.154;P=0.034<0.05).
