Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the or...Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the originally inert N site within polyaniline(PANI)can be activated for hydrogen evolution by proper d-πinterfacial electronic coupling with metal oxide.As a result,the assynthesized WO3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization,exhibits the electrocatalytic production of hydrogen better than other control samples including W18O49@PANI and most of the reported nobel-metal-free electrocatalysts,with low overpotential of 74 mV at 10 mA·cm−2 and small Tafel slope of 46 mV·dec−1 in 0.5M H2SO4(comparable to commercial Pt/C).The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO3 with similar improvements.展开更多
Lignin is the most promising candidate for producing aromatic compounds from biomass.However,the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions,as these bonds have high disso...Lignin is the most promising candidate for producing aromatic compounds from biomass.However,the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions,as these bonds have high dissociation energy.Electrochemical oxidation,which allows for mild cleavage of C-C bonds,is considered an attractive solution.To achieve low-energy consumption in the valorization of lignin,the use of highly efficient electrocatalysts is essential.In this study,a meticulously designed catalyst consisting of cobalt-doped nickel(oxy)hydroxide on molybdenum disulfide heterojunction was developed.The presence of molybdenum in a high valence state promoted the adsorption of tert-butyl hydroperoxide,leading to the formation of critical radical intermediates.In addition,the incorporation of cobalt doping regulated the electronic structure of nickel,resulting in a lower energy barrier.As a result,the heterojunction catalyst demonstrated a selectivity of 85.36% for cleaving the C_(α)-C_(β)bond in lignin model compound,achieving a substrate conversion of 93.69% under ambient conditions.In addition,the electrocatalyst depolymerized 49.82 wt% of soluble fractions from organosolv lignin(OL),resulting in a yield of up to 13 wt% of aromatic monomers.Significantly,the effectiveness of the prepared electrocatalyst was also demonstrated using industrial Kraft lignin(KL).Therefore,this research offers a practical approach for implementing electrocatalytic oxidation in lignin refining.展开更多
In this study,a sulfur–phosphorus co-doped nanocarbon(SPC)catalyst was syn-thesized using a straightforward one-step colloidal carbonization method and demonstrated high performance in the metal-free direct oxidation...In this study,a sulfur–phosphorus co-doped nanocarbon(SPC)catalyst was syn-thesized using a straightforward one-step colloidal carbonization method and demonstrated high performance in the metal-free direct oxidation of alcohols to aldehydes.This metal-free SPC catalyst showed exceptional efficiency,achiev-ing a conversion rate of 90%for benzyl alcohol and a selectivity of 94%toward benzaldehyde within only 1 h at 130◦C.Moreover,it displays exceptional cycle stability and a high turnover frequency(17.1×10-3 mol g-1 h-1).Theoretical analysis suggested that the catalyst’s superior performance is attributed to the presence of unsaturated edge defects and S-P-moieties,which increase the density of states at the Fermi level,lower the band gap energy,and promote electron localization.Additionally,the doping introduces cooperative co-active S-P-C sites,facilitating a synergistic multisite catalytic effect that lowers the energy barriers.These findings represent a significant advancement in the field of metal-free direct alcohol oxidation.展开更多
基金The authors appreciate the supports from the National Research Foundation(NRF),Prime Minister’s Office,Singapore,under its Campus for Research Excellence and Technological Enterprise(CREATE)programme.We also acknowledge financial support from the academic research fund AcRF tier 2(M4020246,ARC10/15),Ministry of Education,Singapore.
文摘Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the originally inert N site within polyaniline(PANI)can be activated for hydrogen evolution by proper d-πinterfacial electronic coupling with metal oxide.As a result,the assynthesized WO3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization,exhibits the electrocatalytic production of hydrogen better than other control samples including W18O49@PANI and most of the reported nobel-metal-free electrocatalysts,with low overpotential of 74 mV at 10 mA·cm−2 and small Tafel slope of 46 mV·dec−1 in 0.5M H2SO4(comparable to commercial Pt/C).The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO3 with similar improvements.
基金supported by the National Science Fund for Distinguished Young Scholars(grant no.31925028)the National Natural Science Foundation of China(grant no.22102019)the Natural Science Foundation of Heilongjiang Province(no.YQ2021C005).
文摘Lignin is the most promising candidate for producing aromatic compounds from biomass.However,the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions,as these bonds have high dissociation energy.Electrochemical oxidation,which allows for mild cleavage of C-C bonds,is considered an attractive solution.To achieve low-energy consumption in the valorization of lignin,the use of highly efficient electrocatalysts is essential.In this study,a meticulously designed catalyst consisting of cobalt-doped nickel(oxy)hydroxide on molybdenum disulfide heterojunction was developed.The presence of molybdenum in a high valence state promoted the adsorption of tert-butyl hydroperoxide,leading to the formation of critical radical intermediates.In addition,the incorporation of cobalt doping regulated the electronic structure of nickel,resulting in a lower energy barrier.As a result,the heterojunction catalyst demonstrated a selectivity of 85.36% for cleaving the C_(α)-C_(β)bond in lignin model compound,achieving a substrate conversion of 93.69% under ambient conditions.In addition,the electrocatalyst depolymerized 49.82 wt% of soluble fractions from organosolv lignin(OL),resulting in a yield of up to 13 wt% of aromatic monomers.Significantly,the effectiveness of the prepared electrocatalyst was also demonstrated using industrial Kraft lignin(KL).Therefore,this research offers a practical approach for implementing electrocatalytic oxidation in lignin refining.
基金National Natural Science Foundation of China,Grant/Award Numbers:31925028,32301541,22102019。
文摘In this study,a sulfur–phosphorus co-doped nanocarbon(SPC)catalyst was syn-thesized using a straightforward one-step colloidal carbonization method and demonstrated high performance in the metal-free direct oxidation of alcohols to aldehydes.This metal-free SPC catalyst showed exceptional efficiency,achiev-ing a conversion rate of 90%for benzyl alcohol and a selectivity of 94%toward benzaldehyde within only 1 h at 130◦C.Moreover,it displays exceptional cycle stability and a high turnover frequency(17.1×10-3 mol g-1 h-1).Theoretical analysis suggested that the catalyst’s superior performance is attributed to the presence of unsaturated edge defects and S-P-moieties,which increase the density of states at the Fermi level,lower the band gap energy,and promote electron localization.Additionally,the doping introduces cooperative co-active S-P-C sites,facilitating a synergistic multisite catalytic effect that lowers the energy barriers.These findings represent a significant advancement in the field of metal-free direct alcohol oxidation.
