低温熔盐辅助铈掺杂钴基氢氧化物用于工业级电催化析氧反应

Ce-doped cobalt-based hydroxide assisted with low-temperature molten salt for industrial oxygen evolution reaction

开发低成本、高性能的析氧电催化剂提升电化学水分解的效率,对于氢能的大规模利用具有重要的意义。钴基氢氧化物是一类极具潜力的析氧(OER)电催化剂,但是较差的导电性与催化活性严重制约了其应用推广。本研究采用一步低温熔盐法合成了铈掺杂的硝酸氢氧化钴电催化剂(Ce-CoNH/CF)。该催化剂在1 mol/L KOH电解液中具有最低的过电位(448 mV@1000 mA/cm^(2))。塔菲尔(Tafel)斜率、循环伏安(CV)和电化学阻抗谱(EIS)测试表明,快速的反应动力学、高效的电化学活性比表面积(ECSA)和极低的电荷转移电阻(Rct)共同作用使得催化剂具有优异的性能。并且在实验室条件下的模拟工业化测试也表明,Ce-CoNH/CF在工业级高温、高浓度的电解液(6 mol/L KOH,70℃)中同样展现出了出色的析氧性能。

Developing low cost and high-performance oxygen evolution electrocatalysts is significant to improve the efficiency of water electrolysis for large-scale hydrogen production.Cobalt hydroxide is a promising electrocatalyst for oxygen evolution reaction(OER),but its poor conductivity and activity seriously restrict the practical application.A simple one-step low temperature molten salt method was applied to successfully synthesize the Ce-doped cobalt hydroxide nitrate(Ce-CoNH/CF),which exhibits outstanding OER performance with a low overpotential of 448 mV at the current density of 1000 mA/cm^(2) in 1 mol/L KOH.The remarkable performance of Ce-CoNH/CF electrode in OER may be the comprehensive result of fast reaction kinetics,large electrochemical active specific surface area(ECSA)and small charge transfer resistance(Rct)as revealed by the Tafel,cyclic voltammetry(CV)and electrochemical impedance spectra(EIS)analysis.Under the simulated industrial test conditions(6 mol/L KOH,70℃),the Ce-CoNH/CF electrode still displays excellent OER performance.