Owing to the intrinsically sluggish kinetics of urea oxidation reaction(UOR)involving a six-electron transfer process,developing efficient UOR electrocatalyst is a great challenge remained to be overwhelmed.Herein,by ...Owing to the intrinsically sluggish kinetics of urea oxidation reaction(UOR)involving a six-electron transfer process,developing efficient UOR electrocatalyst is a great challenge remained to be overwhelmed.Herein,by taking advantage of 2-Methylimidazole,of which is a kind of alkali in water and owns strong coordination ability to Co^(2+)in methanol,trace Co(1.0 mol%)addition was found to induce defect engineering onα-Ni(OH)_(2)in a dual-solvent system of water and methanol.Physical characterization results revealed that the synthesized electrocatalyst(WM-Ni_(0.99)Co_(0.01)(OH)_(2))was a kind of defective nanosheet with thickness around 5-6 nm,attributing to the synergistic effect of Co doping and defect engineering,its electron structure was finely altered,and its specific surface a rea was tremendously enlarged from 68 to 172.3 m^(2)g^(-1).With all these merits,its overpotential to drive 10 mA cm^(-2)was reduced by 110 mV.Besides,the interfacial behavior of UOR was also well deciphered by operando electrochemical impedance spectroscopy.展开更多
The oxygen evolution reaction(OER)with sluggish reaction kinetics and large overpotential is the critical reaction in water splitting that is promising for energy storage and conversion.Layered double hydroxides(LDHs)...The oxygen evolution reaction(OER)with sluggish reaction kinetics and large overpotential is the critical reaction in water splitting that is promising for energy storage and conversion.Layered double hydroxides(LDHs),due to their unique lamellar structure and flexibility of chemical component,are very competing material candidates for OER.Herein,the morphology structure and the electronic structure of LDHs were simultaneously tuned to improve the OER catalytic activity by mild solvothermal reduction using ethylene glycol.The increased surface area,the introduction of oxygen vacancies and the construction of hierarchical structure greatly enhanced the electro-catalytic activity of LDHs for OER.The as-prepared LDHs showed a lower over-potential as low as 276 mV at a current density of 10 mA cm-2,and a small Tafel slope of 40.3 mV dec-1 accompanied with good stability.This work provides an efficient way to the design and optimization of advanced catalysts in the future.展开更多
Oxygen evolution reaction(OER)is a bottleneck process for many electrochemical devices due to the sluggish kinetics,for which advanced electrocatalysts should be carefully designed.Nickle-based materials have been ext...Oxygen evolution reaction(OER)is a bottleneck process for many electrochemical devices due to the sluggish kinetics,for which advanced electrocatalysts should be carefully designed.Nickle-based materials have been extensively studied to catalyze OER.However,their performances are still below the expectation and the active sites are often controversial.Herein,we have successfully modulated the electronic and surface properties of layeredβ-Ni(OH)2 by the interlayer ligand engineering,aiming to design novel efficient electrocatalysts and unveil the catalysis mechanism.By one-step solvothermal reaction,alkoxyl substitutedβ-Ni(OH)2 with variable interlayer distances is obtained,and the ethoxyl substituted one(NiEt)shows great potential for efficient OER.With the assistance of powder X-ray diffraction and crystalline structure computational simulation,the formula of alkoxyl substitutedβ-Ni(OH)2 are determined.Operando X-ray absorption spectroscopy studies combined with ex-situ analyses revealed that the critical active species of NiEt is formed via hydroxylation and subsequent de-protonation,with high valent Niδ+(3<δ≤3.66).The corresponding catalytic reaction pathway and mechanism are proposed.展开更多
基金supported by the Central South University Scientific Research Foundation for Post-doctor(Grant No.:140050052)the National Natural Science Foundation of China(Grant No.:52204325)
文摘Owing to the intrinsically sluggish kinetics of urea oxidation reaction(UOR)involving a six-electron transfer process,developing efficient UOR electrocatalyst is a great challenge remained to be overwhelmed.Herein,by taking advantage of 2-Methylimidazole,of which is a kind of alkali in water and owns strong coordination ability to Co^(2+)in methanol,trace Co(1.0 mol%)addition was found to induce defect engineering onα-Ni(OH)_(2)in a dual-solvent system of water and methanol.Physical characterization results revealed that the synthesized electrocatalyst(WM-Ni_(0.99)Co_(0.01)(OH)_(2))was a kind of defective nanosheet with thickness around 5-6 nm,attributing to the synergistic effect of Co doping and defect engineering,its electron structure was finely altered,and its specific surface a rea was tremendously enlarged from 68 to 172.3 m^(2)g^(-1).With all these merits,its overpotential to drive 10 mA cm^(-2)was reduced by 110 mV.Besides,the interfacial behavior of UOR was also well deciphered by operando electrochemical impedance spectroscopy.
基金supported by the Fundamental Research Funds for the Central Universities (531107051102)the National Natural Science Foundation of China (51402100, 21573066, 21522305)+1 种基金the Provincial Natural Science Foundation of Hunan (2016TP1009)the Shenzhen Discovery Funding (JCYJ20170306141659388)
文摘The oxygen evolution reaction(OER)with sluggish reaction kinetics and large overpotential is the critical reaction in water splitting that is promising for energy storage and conversion.Layered double hydroxides(LDHs),due to their unique lamellar structure and flexibility of chemical component,are very competing material candidates for OER.Herein,the morphology structure and the electronic structure of LDHs were simultaneously tuned to improve the OER catalytic activity by mild solvothermal reduction using ethylene glycol.The increased surface area,the introduction of oxygen vacancies and the construction of hierarchical structure greatly enhanced the electro-catalytic activity of LDHs for OER.The as-prepared LDHs showed a lower over-potential as low as 276 mV at a current density of 10 mA cm-2,and a small Tafel slope of 40.3 mV dec-1 accompanied with good stability.This work provides an efficient way to the design and optimization of advanced catalysts in the future.
基金This work was supported by the Fundamental Research Funds for the Central Universities(531107051102)the National Natural Science Foundation of China(51402100,21825201,21573066,21805080,21902047)the Provincial Natural Science Foundation of Hunan(2016TP1009,2020JJ5045).
文摘Oxygen evolution reaction(OER)is a bottleneck process for many electrochemical devices due to the sluggish kinetics,for which advanced electrocatalysts should be carefully designed.Nickle-based materials have been extensively studied to catalyze OER.However,their performances are still below the expectation and the active sites are often controversial.Herein,we have successfully modulated the electronic and surface properties of layeredβ-Ni(OH)2 by the interlayer ligand engineering,aiming to design novel efficient electrocatalysts and unveil the catalysis mechanism.By one-step solvothermal reaction,alkoxyl substitutedβ-Ni(OH)2 with variable interlayer distances is obtained,and the ethoxyl substituted one(NiEt)shows great potential for efficient OER.With the assistance of powder X-ray diffraction and crystalline structure computational simulation,the formula of alkoxyl substitutedβ-Ni(OH)2 are determined.Operando X-ray absorption spectroscopy studies combined with ex-situ analyses revealed that the critical active species of NiEt is formed via hydroxylation and subsequent de-protonation,with high valent Niδ+(3<δ≤3.66).The corresponding catalytic reaction pathway and mechanism are proposed.
