摘要
The electrocatalytic oxygen evolution reaction(OER)plays a critical role in the hydrogen energy industry[1–3].However,multiple electron transfer results in a sluggish kinetic process in the OER[4].The development of high-efficiency and low-cost OER catalysts is one of the keys to accelerating the kinetic process and widening practical OER applications.The spineltype transition-metal oxides(AB_(2)O_(4))have been used as OER electrocatalysts because of their potential activity and stability as the substitute of precious metals in the alkaline OER process[5].However,the electrochemical activity is limited by the less reactive sites and poor electrical conductivity owing to unsuitable geometric and electronic structures.
催化剂的几何构型和电子结构对催化剂的性能有重大影响.在此我们以过渡金属铁、钴、锌分别掺杂尖晶石型氧化物MnCo_(2)O_(4)为理论模型,研究过渡金属原子掺杂对MnCo_(2)O_(4)几何构型和电子结构的调控机制及其对氧析出反应的作用机理.由于掺杂原子电负性的差异,通过掺杂会引起晶格收缩和电子结构重组.本文利用密度泛函理论计算预测:结构演变将激活晶格氧的反应性,不仅增强了尖晶石型氧化物的本征导电性,而且调控了该催化剂对中间体的吸附能力,实现了调节电压决定步骤和降低理论过电位的目的.通过理论筛选和实验发现:铁掺杂的MnCo_(2)O_(4)在氧析出反应中具有较低的过电位和良好的稳定性.
基金
financially supported by the National Natural Science Foundation of China (61774033)。
