Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high...Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.展开更多
Electrochemical CO2 reduction is a promising strategy for the utilization of CO2 and intermittent excess electricity.Cu is the only single metal catalyst that can electrochemically convert CO2 into multicarbon product...Electrochemical CO2 reduction is a promising strategy for the utilization of CO2 and intermittent excess electricity.Cu is the only single metal catalyst that can electrochemically convert CO2 into multicarbon products.However,Cu exhibits an unfavorable activity and selectivity for the generation of C2 products because of the insufficient amount of CO*provided for the C‐C coupling.Based on the strong CO2 adsorption and ultrafast reaction kinetics of CO*formation on Pd,an intimate CuPd(100)interface was designed to lower the intermediate reaction barriers and improve the efficiency of C2 product formation.Density functional theory(DFT)calculations showed that the CuPd(100)interface enhanced the CO2 adsorption and decreased the CO2*hydrogenation energy barrier,which was beneficial for the C‐C coupling.The potential‐determining step(PDS)barrier of CO2 to C2 products on the CuPd(100)interface was 0.61 eV,which was lower than that on Cu(100)(0.72 eV).Encouraged by the DFT calculation results,the CuPd(100)interface catalyst was prepared by a facile chemical solution method and characterized by transmission electron microscopy.CO2 temperature‐programmed desorption and gas sensor experiments further confirmed the enhancement of the CO2 adsorption and CO2*hydrogenation ability of the CuPd(100)interface catalyst.Specifically,the obtained CuPd(100)interface catalyst exhibited a C2 Faradaic efficiency of 50.3%±1.2%at‒1.4 VRHE in 0.1 M KHCO3,which was 2.1 times higher than that of the Cu catalyst(23.6%±1.5%).This study provides the basis for the rational design of Cu‐based electrocatalysts for the generation of multicarbon products by fine‐tuning the intermediate reaction barriers.展开更多
H+ doped polyaniline nanofibre(PH) was synthesized by interfacial polymerization and polyanilines doped with Li salt(PLI and PHLI) were prepared by immersing emeraldine base(EB) and H+ doped polyaniline in 1 mol/L LiP...H+ doped polyaniline nanofibre(PH) was synthesized by interfacial polymerization and polyanilines doped with Li salt(PLI and PHLI) were prepared by immersing emeraldine base(EB) and H+ doped polyaniline in 1 mol/L LiPF6/(EC-EMC-DMC),respectively.PH,PLI and PHLI were all characterized by scanning electron microscopy(SEM) and Fourier transform infrared(FT-IR) spectrometry.With 1 mol/L LiPF6/(EC-EMC-DMC) as electrolyte,PH,PHLI and PLI were used as the active materials of symmetric non-aqueous redox supercapacitors.PLI shows the highest initial specific capacitance of 120 F/g(47 F/g for PH and 66 F/g for PHLI) among three samples.After 500 cycles,the specific capacitance of PLI remains 75 F/g,indicating the good cycleability.展开更多
Nonprecious metal-based oxygen reduction reaction(ORR)electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts;how...Nonprecious metal-based oxygen reduction reaction(ORR)electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts;however,it is still a challenge to achieve superior ORR performances,especially in acidic media.Herein,by pyrolysis of mixed precursors of diammonium phosphate,melamine and hemin,we prepared a nanocomposite catalyst(denoted as FeP@PGL)composed of nitrogen-doped carbon nanosheets with embedded FeP nanoparticles(NPs),which were encapsulated by in-situ formed phosphorus-doped graphene layers.It is found that phosphorous was preferentially doped in the coating layers on FeP NPs,instead of in the carbon nanosheets.The FeP@PGL catalyst exhibited excellent ORR performance,with the onset and half-wave potential up to 1.01 and 0.90 V vs.the reversible hydrogen electrode(RHE)in alkaline media,and0.95 and 0.81 V vs.RHE in acidic media,respectively.By thorough microscopy and spectroscopy characterizations,the interfacial charge transfer between the encapsulated FeP NPs and P-doped graphene layers was identified,and the local work function of the catalyst surface was also reduced by the interfacial interaction.The interfacial synergy between the encapsulated FeP and phosphorus-doped graphene layers was essential to enhance the ORR performance.This study not only demonstrates the promising ORR properties of the encapsulated-FeP-based nanocomposite catalyst,but also provides direct evidence of the interfacial charge transfer effect and its role in ORR process.展开更多
Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper(AP/PB-GP) made of reduced graphene oxide via...Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper(AP/PB-GP) made of reduced graphene oxide via interfacial crosslinking with 1-aminopyrene(AP) and 1-pyrenebutyrat(PB) small molecules. The AP/PB-GP with thickness of over ten micrometer delivers a record-high toughness(~69.67 ± 15.3 MJ m^(-3) in average), simultaneously with superior strength(close to 1 GPa), allowing an impressive specific penetration energy absorption(~0.17 MJ kg^(-1)) at high impact velocities when used for ballistic impact protection. Detailed interfacial and structural analysis reveals that the reinforcement is synergistically determined by π-π interaction and H-bonding linkage between adjacent graphene lamellae. Especially, the defective pores within the graphene platelets benefit the favorable adsorption of the pyrene-containing molecules, which imperatively maximizes the interfacial binding, facilitating deflecting crack and plastic deformation under loading. Density functional theory simulation suggests that the coupling between the polar functional groups, e.g., –COOH, at the edges of graphene platelets and –NH_(2) and –COOH of AP/PB are critical to the formation of hydrogen bonding network.展开更多
Water electrolysis to produce H2 is a promising strategy for generating a renewable fuel.However,the sluggish-kinetics and low value-added anodic oxygen evolution reaction(OER)restricts the overall energy conversion e...Water electrolysis to produce H2 is a promising strategy for generating a renewable fuel.However,the sluggish-kinetics and low value-added anodic oxygen evolution reaction(OER)restricts the overall energy conversion efficiency.Herein we report a strategy of boosting H_(2)production at low voltages by replacing OER with a bioelectrochemical cascade reaction at a triphase bioanode.In the presence of oxygen,oxidase enzymes can convert biomass into valuable products,and concurrently generate H_(2)O_(2) that can be further electrooxidized at the bioanode.Benefiting from the efficient oxidase kinetics at an oxygen-rich triphase bioanode and the more favorable thermodynamics of H_(2)O_(2)oxidation than that of OER,the cell voltage and energy consumption are reduced by~0.70 V and~36%,respectively,relative to regular water electrolysis.This leads to an efficient H_(2)production at the cathode and valuable product generation at the bioanode.Integration of a bioelectrochemical cascade into the water splitting process provides an energy-efficient and promising pathway for achieving a renewable fuel.展开更多
文摘Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.
文摘Electrochemical CO2 reduction is a promising strategy for the utilization of CO2 and intermittent excess electricity.Cu is the only single metal catalyst that can electrochemically convert CO2 into multicarbon products.However,Cu exhibits an unfavorable activity and selectivity for the generation of C2 products because of the insufficient amount of CO*provided for the C‐C coupling.Based on the strong CO2 adsorption and ultrafast reaction kinetics of CO*formation on Pd,an intimate CuPd(100)interface was designed to lower the intermediate reaction barriers and improve the efficiency of C2 product formation.Density functional theory(DFT)calculations showed that the CuPd(100)interface enhanced the CO2 adsorption and decreased the CO2*hydrogenation energy barrier,which was beneficial for the C‐C coupling.The potential‐determining step(PDS)barrier of CO2 to C2 products on the CuPd(100)interface was 0.61 eV,which was lower than that on Cu(100)(0.72 eV).Encouraged by the DFT calculation results,the CuPd(100)interface catalyst was prepared by a facile chemical solution method and characterized by transmission electron microscopy.CO2 temperature‐programmed desorption and gas sensor experiments further confirmed the enhancement of the CO2 adsorption and CO2*hydrogenation ability of the CuPd(100)interface catalyst.Specifically,the obtained CuPd(100)interface catalyst exhibited a C2 Faradaic efficiency of 50.3%±1.2%at‒1.4 VRHE in 0.1 M KHCO3,which was 2.1 times higher than that of the Cu catalyst(23.6%±1.5%).This study provides the basis for the rational design of Cu‐based electrocatalysts for the generation of multicarbon products by fine‐tuning the intermediate reaction barriers.
基金Project(2008AA03Z207) supported by the National Hi-tech Research and Development Program of China
文摘H+ doped polyaniline nanofibre(PH) was synthesized by interfacial polymerization and polyanilines doped with Li salt(PLI and PHLI) were prepared by immersing emeraldine base(EB) and H+ doped polyaniline in 1 mol/L LiPF6/(EC-EMC-DMC),respectively.PH,PLI and PHLI were all characterized by scanning electron microscopy(SEM) and Fourier transform infrared(FT-IR) spectrometry.With 1 mol/L LiPF6/(EC-EMC-DMC) as electrolyte,PH,PHLI and PLI were used as the active materials of symmetric non-aqueous redox supercapacitors.PLI shows the highest initial specific capacitance of 120 F/g(47 F/g for PH and 66 F/g for PHLI) among three samples.After 500 cycles,the specific capacitance of PLI remains 75 F/g,indicating the good cycleability.
基金supported by the National Natural Science Foundation of China(21773128,21534005,and 21421001)。
文摘Nonprecious metal-based oxygen reduction reaction(ORR)electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts;however,it is still a challenge to achieve superior ORR performances,especially in acidic media.Herein,by pyrolysis of mixed precursors of diammonium phosphate,melamine and hemin,we prepared a nanocomposite catalyst(denoted as FeP@PGL)composed of nitrogen-doped carbon nanosheets with embedded FeP nanoparticles(NPs),which were encapsulated by in-situ formed phosphorus-doped graphene layers.It is found that phosphorous was preferentially doped in the coating layers on FeP NPs,instead of in the carbon nanosheets.The FeP@PGL catalyst exhibited excellent ORR performance,with the onset and half-wave potential up to 1.01 and 0.90 V vs.the reversible hydrogen electrode(RHE)in alkaline media,and0.95 and 0.81 V vs.RHE in acidic media,respectively.By thorough microscopy and spectroscopy characterizations,the interfacial charge transfer between the encapsulated FeP NPs and P-doped graphene layers was identified,and the local work function of the catalyst surface was also reduced by the interfacial interaction.The interfacial synergy between the encapsulated FeP and phosphorus-doped graphene layers was essential to enhance the ORR performance.This study not only demonstrates the promising ORR properties of the encapsulated-FeP-based nanocomposite catalyst,but also provides direct evidence of the interfacial charge transfer effect and its role in ORR process.
基金supported by the National Natural Science Foundation of China (51772282,51972299)funding from Hefei Center for Physical Science and Technology。
文摘Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper(AP/PB-GP) made of reduced graphene oxide via interfacial crosslinking with 1-aminopyrene(AP) and 1-pyrenebutyrat(PB) small molecules. The AP/PB-GP with thickness of over ten micrometer delivers a record-high toughness(~69.67 ± 15.3 MJ m^(-3) in average), simultaneously with superior strength(close to 1 GPa), allowing an impressive specific penetration energy absorption(~0.17 MJ kg^(-1)) at high impact velocities when used for ballistic impact protection. Detailed interfacial and structural analysis reveals that the reinforcement is synergistically determined by π-π interaction and H-bonding linkage between adjacent graphene lamellae. Especially, the defective pores within the graphene platelets benefit the favorable adsorption of the pyrene-containing molecules, which imperatively maximizes the interfacial binding, facilitating deflecting crack and plastic deformation under loading. Density functional theory simulation suggests that the coupling between the polar functional groups, e.g., –COOH, at the edges of graphene platelets and –NH_(2) and –COOH of AP/PB are critical to the formation of hydrogen bonding network.
基金supported by the National Key R&D Program of China(2019YFA0709200)the National Natural Science Foundation of China(21988102,51772198 and 21975171)。
文摘Water electrolysis to produce H2 is a promising strategy for generating a renewable fuel.However,the sluggish-kinetics and low value-added anodic oxygen evolution reaction(OER)restricts the overall energy conversion efficiency.Herein we report a strategy of boosting H_(2)production at low voltages by replacing OER with a bioelectrochemical cascade reaction at a triphase bioanode.In the presence of oxygen,oxidase enzymes can convert biomass into valuable products,and concurrently generate H_(2)O_(2) that can be further electrooxidized at the bioanode.Benefiting from the efficient oxidase kinetics at an oxygen-rich triphase bioanode and the more favorable thermodynamics of H_(2)O_(2)oxidation than that of OER,the cell voltage and energy consumption are reduced by~0.70 V and~36%,respectively,relative to regular water electrolysis.This leads to an efficient H_(2)production at the cathode and valuable product generation at the bioanode.Integration of a bioelectrochemical cascade into the water splitting process provides an energy-efficient and promising pathway for achieving a renewable fuel.
