Herein,Pd nanoparticles loaded Co_(3)O_(4)catalysts(Pd@Co_(3)O_(4))are constructed from zeolitic imidazolate framework-67(ZIF-67)for the ethanol oxidation reaction(EOR).It is demonstrated for the first time that the e...Herein,Pd nanoparticles loaded Co_(3)O_(4)catalysts(Pd@Co_(3)O_(4))are constructed from zeolitic imidazolate framework-67(ZIF-67)for the ethanol oxidation reaction(EOR).It is demonstrated for the first time that the electrochemical conversion of Co_(3)O_(4)support would result in the charge distribution alignment at the Pd/Co_(3)O_(4)interface and induce the formation of highly reactive Pd-O species(PdO^(*)),which can further catalyze the consequent reactions of the intermediates of the ethanol oxidation.The catalyst,Pd@Co_(3)O_(4)-450,obtained under the optimized conditions exhibits excellent EOR performance with a high mass activity of 590 mA mg-1,prominent operational stability,and extraordinary capability for the electro-oxidation of acetaldehyde intermediates.Importantly,the detailed mechanism investigation reveals that Pd@Co_(3)O_(4)-450 could be benefit to the C-C bond cleavage to promote the desirable C1 pathway for the ethanol oxidation reaction.The present strategy based on the metal-support interaction of the catalyst might provide valuable inspiration for the design of high-performing catalysts for the ethanol oxidation reaction.展开更多
With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environmen...With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.展开更多
CO and formaldehyde(HCHO)oxidation reactions were investigated over mesoporous Ag/Co3O4 catalysts prepared by one-pot(OP)and impregnation(IM)methods.It was found that the one-pot method was superior to the impregnatio...CO and formaldehyde(HCHO)oxidation reactions were investigated over mesoporous Ag/Co3O4 catalysts prepared by one-pot(OP)and impregnation(IM)methods.It was found that the one-pot method was superior to the impregnation method for synthesizing Ag/Co3O4 catalysts with high activity for both reactions.It was also found that the catalytic behavior of mesoporous Co3O4 and Ag/Co3O4 catalysts for the both reactions was different.And the addition of silver on mesoporous Co3O4 did not always enhance the catalytic activity of final catalyst for CO oxidation at room temperature(20 C),but could significantly improve the catalytic activity of final catalyst for HCHO oxidation at low temperature(90 C).The high surface area,uniform pore structure and the pretty good dispersion degree of the silver particle should be responsible for the excellent low-temperature CO oxidation activity.However,for HCHO oxidation,the addition of silver played an important role in the activity enhancement.And the silver particle size and the reducibility of Co3O4 should be indispensable for the high activity of HCHO oxidation at low temperature.展开更多
Up to this date,researchers are still facing difficulties to expand the technology of direct methanol fuel cells(DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor perfor...Up to this date,researchers are still facing difficulties to expand the technology of direct methanol fuel cells(DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor performance due to CO poisoning of the leading-high cost anode catalyst.In line with this,we have successfully modified the morphological structure and composition of low cost cobalt based-metal oxides,MCo_2O_4(M = Zn and Ni),with the simple and noble use of polyvinyl pyrrolidone(PVP) as growth modifier and surface stabilizer during the synthesis of nanoparticles in our previous reports,which shown high electrocatalytic activity and strong stability.Due to the good performance of our PVP modified MCo_2O_4 towards pseudocapacitor and oxygen evolution reaction applications,we decided to extend our research study to methanol oxidation reaction.Remarkably,PVP modified Ni Co_2O_4 electrode directly grown on nickel foam substrate via a simple hydrothermal process exhibited better performance compared with PVP modified ZnCo_2O_4 and NiCo_2O_4 without PVP.It had obtained a remarkably low onset potential of 0.285 V and high current density of 280 m A cm^(-2),and shown great stability and high poison tolerance during a continuous CV cycling and Chronoamperometry test,which attained high efficiency of 86.86%and 98.52%,respectively.These positive results of PVP modified Ni Co_2O_4 electrode towards MOR might be attributed to its hierarchical 3 D nanostructures with highly mesoporous surface and large surface area which may have provided numerous electroactive sites,and the exceptional corrosion stability of Ni Co_2O_4 electrode in alkaline solution.展开更多
基金supported by the National Natural Science Foundation of China(21336005)the Ministry of Science and Technology of China(2014EG111224)+1 种基金the National Key R&D Program of China(2021YFB4001200)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_3185)。
文摘Herein,Pd nanoparticles loaded Co_(3)O_(4)catalysts(Pd@Co_(3)O_(4))are constructed from zeolitic imidazolate framework-67(ZIF-67)for the ethanol oxidation reaction(EOR).It is demonstrated for the first time that the electrochemical conversion of Co_(3)O_(4)support would result in the charge distribution alignment at the Pd/Co_(3)O_(4)interface and induce the formation of highly reactive Pd-O species(PdO^(*)),which can further catalyze the consequent reactions of the intermediates of the ethanol oxidation.The catalyst,Pd@Co_(3)O_(4)-450,obtained under the optimized conditions exhibits excellent EOR performance with a high mass activity of 590 mA mg-1,prominent operational stability,and extraordinary capability for the electro-oxidation of acetaldehyde intermediates.Importantly,the detailed mechanism investigation reveals that Pd@Co_(3)O_(4)-450 could be benefit to the C-C bond cleavage to promote the desirable C1 pathway for the ethanol oxidation reaction.The present strategy based on the metal-support interaction of the catalyst might provide valuable inspiration for the design of high-performing catalysts for the ethanol oxidation reaction.
基金supported by the National Natural Science Foundation of China (No.52364022)the Natural Science Foundation of Guangxi Province,China (Nos.2023JJA160192 and 2021GXNSFAA220096)+1 种基金the Guangxi Science and Technology Major Project,China (No.AA23073018)the Guangxi Chongzuo Science and Technology Plan,China (No.2023ZY00503).
文摘With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.
基金supported financially by the Program for New Century Excellent Talents in University (NCET-09-0256)the Fundamental Research Funds for the Central Universities (DUT13LK27)the National Nature Science Foundation of China (No.21377016)
文摘CO and formaldehyde(HCHO)oxidation reactions were investigated over mesoporous Ag/Co3O4 catalysts prepared by one-pot(OP)and impregnation(IM)methods.It was found that the one-pot method was superior to the impregnation method for synthesizing Ag/Co3O4 catalysts with high activity for both reactions.It was also found that the catalytic behavior of mesoporous Co3O4 and Ag/Co3O4 catalysts for the both reactions was different.And the addition of silver on mesoporous Co3O4 did not always enhance the catalytic activity of final catalyst for CO oxidation at room temperature(20 C),but could significantly improve the catalytic activity of final catalyst for HCHO oxidation at low temperature(90 C).The high surface area,uniform pore structure and the pretty good dispersion degree of the silver particle should be responsible for the excellent low-temperature CO oxidation activity.However,for HCHO oxidation,the addition of silver played an important role in the activity enhancement.And the silver particle size and the reducibility of Co3O4 should be indispensable for the high activity of HCHO oxidation at low temperature.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) - Grants funded by the Ministry of Trade,Industry and Energy (MOTIE) (No.20174010201160)the National Research Foundation of Korea (NRF) - Grant funded by the Ministry of Education (No.20090093816),Republic of Korea
文摘Up to this date,researchers are still facing difficulties to expand the technology of direct methanol fuel cells(DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor performance due to CO poisoning of the leading-high cost anode catalyst.In line with this,we have successfully modified the morphological structure and composition of low cost cobalt based-metal oxides,MCo_2O_4(M = Zn and Ni),with the simple and noble use of polyvinyl pyrrolidone(PVP) as growth modifier and surface stabilizer during the synthesis of nanoparticles in our previous reports,which shown high electrocatalytic activity and strong stability.Due to the good performance of our PVP modified MCo_2O_4 towards pseudocapacitor and oxygen evolution reaction applications,we decided to extend our research study to methanol oxidation reaction.Remarkably,PVP modified Ni Co_2O_4 electrode directly grown on nickel foam substrate via a simple hydrothermal process exhibited better performance compared with PVP modified ZnCo_2O_4 and NiCo_2O_4 without PVP.It had obtained a remarkably low onset potential of 0.285 V and high current density of 280 m A cm^(-2),and shown great stability and high poison tolerance during a continuous CV cycling and Chronoamperometry test,which attained high efficiency of 86.86%and 98.52%,respectively.These positive results of PVP modified Ni Co_2O_4 electrode towards MOR might be attributed to its hierarchical 3 D nanostructures with highly mesoporous surface and large surface area which may have provided numerous electroactive sites,and the exceptional corrosion stability of Ni Co_2O_4 electrode in alkaline solution.
