Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spine...Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spinel synthesis methods with prolonged high-temperature reactions lack kinetic precision,hindering the balance between controlled doping and highly active two-dimensional(2D)porous structures design.This significantly impedes the identification of electron configuration-dependent active sites in doped 2D nickel-based spinels.Herein,we present a microwave shock method for the preparation of 2D porous NiCo_(2)O_(4)spinel.Utilizing the transient on-off property of microwave pulses for precise heteroatom doping and 2D porous structural design,non-metal doping(boron,phosphorus,and sulfur)with distinct extranuclear electron disparities serves as straightforward examples for investigation.Precise tuning of lattice parameter reveals the impact of covalent bond strength on NiCo_(2)O_(4)structural stability.The introduced defect levels induce unpaired d-electrons in transition metals,enhancing the adsorption of electron-donating amino groups in urea molecules.Simultaneously,Bode plots confirm the impact mechanism of rapid electron migration caused by reduced band gaps on UOR activity.The prepared phosphorus-doped 2D porous NiCo_(2)O_(4),with optimal electron configuration control,outperforms most reported spinels.This controlled modification strategy advances understanding theoretical structure-activity mechanisms of high-performance 2D spinels in UOR.展开更多
Urea and oxalic acid are critical component in various chemical manufacturing industries.However,achieving simultaneous generation of urea and oxalic acid in a continuous-flow electrolyzer is a challenge.Herein,we rep...Urea and oxalic acid are critical component in various chemical manufacturing industries.However,achieving simultaneous generation of urea and oxalic acid in a continuous-flow electrolyzer is a challenge.Herein,we report a continuous-flow electrolyzer equipped with 9-square centime-ter-effective area gas diffusion electrodes(GDE)which can simultaneously catalyze the glycerol oxidation reaction in the anode region and the reduction reaction of CO_(2) and nitrate in the cathode region,producing oxalic acid and urea at both the anode and cathode,respectively.The current density at low cell voltage(0.9 V)remained above 18.7 mA cm^(-2) for 10 consecutive electrolysis cycles(120 h in total),and the Faraday efficiency of oxalic acid(67.1%) and urea(70.9%)did not decay.Experimental and theoretical studies show that in terms of the formation of C-N bond at the cathode,Pd-sites can provide protons for the hydrogenation process of CO_(2) and NO_(3)^(-),Cu-sites can promote the generation of *COOH and Bi-sites can stabilize *COOH.In addition,in terms of glycerol oxidation,the introduction of Cu and Bi into Pd metallene promotes the oxidation of hydroxyl groups and the cleavage of C-C bond in glycerol molecules,respectively.展开更多
Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the devel...Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather challenging.Herein,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea production.Our results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic properties.Interestingly,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side reactions.The outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active sites.Our findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.展开更多
Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns.Electrocatalytic C-N coupling by converting nitrate and CO_(2) into urea und...Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns.Electrocatalytic C-N coupling by converting nitrate and CO_(2) into urea under ambient conditions represents a promising alternative process.But it was still limited by the strong competition between nitrate electrochemical reduction(NO_(3)ER) and CO_(2) electrochemical reduction(CO_(2)ER).Here,Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n heterostructures are constructed through hydrothermal synthesis and exhibited superior performance toward urea electrosynthesis with NO_(3)~-and CO_(2) as feedstocks.The optimized urea yield and Faradaic efficiency over Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2 can reach13.8 mmol h^(-1) g^(-1) and 11.5% at-0.8 V vs.reversible hydrogen electrode,which is much higher than that of bare FeOOH(3.2 mmol h^(-1) g^(-1) and 1.3%),pristine BiVO_(4)(2.0 mmol h^(-1) g^(-1) and 5.4%),and the other Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n(n=1,3,5) heterostructures.Systematic experiments have verified that BiVO_(4)and FeOOH are subreaction active sites towards simultaneous CO_(2)ER and NO_(3)ER,respectively,achieving co-activation of CO_(2) and NO_(3)~-on Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2.Moreover,the urea synthesis via the ^(*)CO and NO*intermediates and C-N coupling was confirmed by the in situ Fourier transform infrared spectroscopy.This work not only alleviates the CO_(2) emission and nitrate pollution but also presents an efficient catalyst for synergistic catalysis towards sustainable urea synthesis.展开更多
Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of...Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems.展开更多
Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environme...Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environmental problems. With the increasing global demand for environmental protection and sustainable development, it is much necessary to develop novel and clean methods for the synthesis of urea.Electrocatalysis provides an efficient and renewable synthesis route that can directly produce urea at room temperature and atmospheric pressure by the coupling of CO_(2) and nitrogenous molecules. In this review, we summarized the most recent advances in electrochemical synthesis of urea via CAN coupling systematically, focusing on the coupling of CO_(2) and different nitrogen sources. And the associated coupling mechanism, catalysts optimization, and electrolyzer design are well discussed. Moreover, the challenges and future directions for electrocatalytic CAN coupling are prospected. This review will provide timely and valuable guidance for others and attract more interests to promote the development of electrochemical synthesis of urea or other valuable chemicals containing CAN bond.展开更多
The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Nort...The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Northwest China.We conducted a two-year field experiment to assess the effects of combining SI with either uncoated urea(U)or PCU on soil NH_(3)emissions,N_(2)O emissions,winter wheat yields,yield-scaled NH_(3)(/NH_(3)),and yield-scaled N_(2)O(/N_(2)O).Five treatments were investigated,no nitrogen(N)fertilizer(N_(0)),U application at 150 kg N ha-1 with and without SI(SI+U and S_(0)+U),and PCU application at 150 kg N ha^(-1) with and without SI(SI+PCU and S_(0)+PCU).The results showed that the NH_(3);emissions increased by 20.98-34.35%following Sl compared to straw removal,mainly due to increases in soil ammonium(NH_(4)^(+)-N)content and water-flled pore space(WFPS).SI resulted in higher N_(2)O emissions than under the So scenario by 13.31-49.23%due to increases in soil inorganic N(SIN)contents,WFPS,and soil microbial biomass.In contrast,the PCU application reduced the SIN contents compared to the U application,reducing the NH_(3)and N_(2)O emissions by 45.99-58.07 and 18.08-53.04%,respectively.Moreover,no significant positive effects of the SI or PCU applications on the winter wheat yield were observed.The lowest /NH_(3) and /N_(2)O values were observed under the S_(0)+PCU and SI+PCU treatments.Our results suggest that single PCU applications and their combination with straw are the optimal agricultural strategies for mitigating gaseous N emissions and maintaining optimal winter wheat yields in Northwest China.展开更多
基金financial support from the National Natural Science Foundation of China(52203070)the Open Fund of State Key Laboratory of New Textile Materials and Advanced Processing Technologies(FZ2022005)+2 种基金the Open Fund of Hubei Key Laboratory of Biomass Fiber and Ecological Dyeing and Finishing(STRZ202203)the financial support provided by the China Scholarship Council(CSC)Visiting Scholar Programfinancial support from Institute for Sustainability,Energy and Resources,The University of Adelaide,Future Making Fellowship。
文摘Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spinel synthesis methods with prolonged high-temperature reactions lack kinetic precision,hindering the balance between controlled doping and highly active two-dimensional(2D)porous structures design.This significantly impedes the identification of electron configuration-dependent active sites in doped 2D nickel-based spinels.Herein,we present a microwave shock method for the preparation of 2D porous NiCo_(2)O_(4)spinel.Utilizing the transient on-off property of microwave pulses for precise heteroatom doping and 2D porous structural design,non-metal doping(boron,phosphorus,and sulfur)with distinct extranuclear electron disparities serves as straightforward examples for investigation.Precise tuning of lattice parameter reveals the impact of covalent bond strength on NiCo_(2)O_(4)structural stability.The introduced defect levels induce unpaired d-electrons in transition metals,enhancing the adsorption of electron-donating amino groups in urea molecules.Simultaneously,Bode plots confirm the impact mechanism of rapid electron migration caused by reduced band gaps on UOR activity.The prepared phosphorus-doped 2D porous NiCo_(2)O_(4),with optimal electron configuration control,outperforms most reported spinels.This controlled modification strategy advances understanding theoretical structure-activity mechanisms of high-performance 2D spinels in UOR.
文摘Urea and oxalic acid are critical component in various chemical manufacturing industries.However,achieving simultaneous generation of urea and oxalic acid in a continuous-flow electrolyzer is a challenge.Herein,we report a continuous-flow electrolyzer equipped with 9-square centime-ter-effective area gas diffusion electrodes(GDE)which can simultaneously catalyze the glycerol oxidation reaction in the anode region and the reduction reaction of CO_(2) and nitrate in the cathode region,producing oxalic acid and urea at both the anode and cathode,respectively.The current density at low cell voltage(0.9 V)remained above 18.7 mA cm^(-2) for 10 consecutive electrolysis cycles(120 h in total),and the Faraday efficiency of oxalic acid(67.1%) and urea(70.9%)did not decay.Experimental and theoretical studies show that in terms of the formation of C-N bond at the cathode,Pd-sites can provide protons for the hydrogenation process of CO_(2) and NO_(3)^(-),Cu-sites can promote the generation of *COOH and Bi-sites can stabilize *COOH.In addition,in terms of glycerol oxidation,the introduction of Cu and Bi into Pd metallene promotes the oxidation of hydroxyl groups and the cleavage of C-C bond in glycerol molecules,respectively.
基金financially supported in China by Natural Science Funds for Distinguished Young Scholars of Heilongjiang Province(No.JC2018004)Natural Science Foundation of Heilongjiang Province of China(No.TD2020B001)in the USA by NSF-CREST Center for Innovation,Research,and Education in Environmental Nanotechnology(CIRE2N)(No.HRD-1736093)
文摘Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather challenging.Herein,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea production.Our results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic properties.Interestingly,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side reactions.The outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active sites.Our findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.
基金financially supported by the Science Foundation of China (92161103, 22071180, and 22104110)。
文摘Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns.Electrocatalytic C-N coupling by converting nitrate and CO_(2) into urea under ambient conditions represents a promising alternative process.But it was still limited by the strong competition between nitrate electrochemical reduction(NO_(3)ER) and CO_(2) electrochemical reduction(CO_(2)ER).Here,Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n heterostructures are constructed through hydrothermal synthesis and exhibited superior performance toward urea electrosynthesis with NO_(3)~-and CO_(2) as feedstocks.The optimized urea yield and Faradaic efficiency over Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2 can reach13.8 mmol h^(-1) g^(-1) and 11.5% at-0.8 V vs.reversible hydrogen electrode,which is much higher than that of bare FeOOH(3.2 mmol h^(-1) g^(-1) and 1.3%),pristine BiVO_(4)(2.0 mmol h^(-1) g^(-1) and 5.4%),and the other Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n(n=1,3,5) heterostructures.Systematic experiments have verified that BiVO_(4)and FeOOH are subreaction active sites towards simultaneous CO_(2)ER and NO_(3)ER,respectively,achieving co-activation of CO_(2) and NO_(3)~-on Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2.Moreover,the urea synthesis via the ^(*)CO and NO*intermediates and C-N coupling was confirmed by the in situ Fourier transform infrared spectroscopy.This work not only alleviates the CO_(2) emission and nitrate pollution but also presents an efficient catalyst for synergistic catalysis towards sustainable urea synthesis.
基金support from the Tangshan Talent Funding Project(Grant No.A202202007)National Natural Science Foundation of China(Grant Nos.22102136 and 21703065)+2 种基金Natural Science Foundation of Hebei Province(Grant Nos.B2018209267 and E2022209039)Natural Science Foundation of Hubei Province(Grant No.2022CFB1001)Department of Education of Hubei Province(Grant No.Q20221701).
文摘Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems.
基金National Natural Science Foundation of China (No. 22202065, 22075092 and U21A20500)。
文摘Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environmental problems. With the increasing global demand for environmental protection and sustainable development, it is much necessary to develop novel and clean methods for the synthesis of urea.Electrocatalysis provides an efficient and renewable synthesis route that can directly produce urea at room temperature and atmospheric pressure by the coupling of CO_(2) and nitrogenous molecules. In this review, we summarized the most recent advances in electrochemical synthesis of urea via CAN coupling systematically, focusing on the coupling of CO_(2) and different nitrogen sources. And the associated coupling mechanism, catalysts optimization, and electrolyzer design are well discussed. Moreover, the challenges and future directions for electrocatalytic CAN coupling are prospected. This review will provide timely and valuable guidance for others and attract more interests to promote the development of electrochemical synthesis of urea or other valuable chemicals containing CAN bond.
基金This work was supported by the National Key R&D Program of China(2021YFD1900700)the National Natural Science Foundation of China(52179046).
文摘The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Northwest China.We conducted a two-year field experiment to assess the effects of combining SI with either uncoated urea(U)or PCU on soil NH_(3)emissions,N_(2)O emissions,winter wheat yields,yield-scaled NH_(3)(/NH_(3)),and yield-scaled N_(2)O(/N_(2)O).Five treatments were investigated,no nitrogen(N)fertilizer(N_(0)),U application at 150 kg N ha-1 with and without SI(SI+U and S_(0)+U),and PCU application at 150 kg N ha^(-1) with and without SI(SI+PCU and S_(0)+PCU).The results showed that the NH_(3);emissions increased by 20.98-34.35%following Sl compared to straw removal,mainly due to increases in soil ammonium(NH_(4)^(+)-N)content and water-flled pore space(WFPS).SI resulted in higher N_(2)O emissions than under the So scenario by 13.31-49.23%due to increases in soil inorganic N(SIN)contents,WFPS,and soil microbial biomass.In contrast,the PCU application reduced the SIN contents compared to the U application,reducing the NH_(3)and N_(2)O emissions by 45.99-58.07 and 18.08-53.04%,respectively.Moreover,no significant positive effects of the SI or PCU applications on the winter wheat yield were observed.The lowest /NH_(3) and /N_(2)O values were observed under the S_(0)+PCU and SI+PCU treatments.Our results suggest that single PCU applications and their combination with straw are the optimal agricultural strategies for mitigating gaseous N emissions and maintaining optimal winter wheat yields in Northwest China.