催化学报 ›› 2020, Vol. 41 ›› Issue (11): 1692-1697.DOI: 10.1016/S1872-2067(20)63628-2

• 论文 • 上一篇    下一篇

镧系元素调控6H相钙钛矿中共面IrO6二聚体的产氧活性

冯尉强, 陈辉, 张琪, 高瑞芹, 邹晓新   

  1. 吉林大学化学学院无机合成与制备化学国家重点实验室, 吉林长春 130012
  • 收稿日期:2020-02-28 修回日期:2020-03-31 出版日期:2020-11-18 发布日期:2020-08-15
  • 通讯作者: 邹晓新
  • 基金资助:
    国家自然科学基金(21771079,21621001);霍英东教育基金(161011);博士后创新人才支持项目(BX20180120);中国博士后科学基金(2018M641771);111计划(B17020).

Lanthanide-regulated oxygen evolution activity of face-sharing IrO6 dimers in 6H-perovskite electrocatalysts

Weiqiang Feng, Hui Chen, Qi Zhang, Ruiqin Gao, Xiaoxin Zou   

  1. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, Jilin, China
  • Received:2020-02-28 Revised:2020-03-31 Online:2020-11-18 Published:2020-08-15
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (21771079, 21621001), Fok Ying Tung Education Foundation (161011), the Postdoctoral Innovative Talent Support Program (BX20180120) and the China Postdoctoral Science Foundation (2018M641771), and the 111 Project (B17020).

摘要: 随着全球气候变暖的加剧和化石能源的日益枯竭,开发清洁无污染的可再生能源变得越来越重要.作为一种清洁无污染、能量密度高的能源载体,氢气被认为是极具应用前景的化石燃料替代品.电解水技术所得氢气纯度高,可以利用风能、太阳能、水能等可再生电能,是未来大规模工业产氢的理想路线之一.电解水过程包括阳极析氧反应和阴极析氢反应两个半反应.其中,阳极析氧反应具有更缓慢的反应动力学,成为水裂解过程的主要限速反应,影响整个电解水器件的效率.质子交换膜电解水技术是目前最先进的电解水技术.寻找在酸性条件下实现高效产氧反应速率的电催化剂对于开发下一代质子交换膜电解水技术具有重要意义.目前,铱的氧化物是在酸性条件下高效、稳定的催化剂.但是,其价格昂贵且资源储量低,不能适合大规模应用.因此,寻找低贵金属含量的高活性产氧催化剂迫在眉睫.
本文以一系列含有镧系元素的6H相钙钛矿结构的Ba3LnIr2O9作为研究对象,探究了其在酸性条件下的产氧电催化性能(Ln代表镧系元素).我们发现,镧系元素可以调控Ba3LnIr2O9结构中共面的IrO6八面体活性亚结构单元.基于密度泛函理论(DFT)计算,我们建立了Ba3LnIr2O9系列结构的理论催化活性趋势,并发现其活性受反应中间吸附产物(吸附氧O*和吸附羟基OH*)的吸附自由能之差(△GO-△GOH)的调控.进一步,为了从电子结构方面揭示△GO-△GOH对催化活性的作用规律,我们计算了Ba3LnIr2O9系列的氧p带中心,并利用计算的氧p带中心和△GO-△GOH建立了典型的火山型曲线.其中位于火山型曲线顶点的Ba3LaIr2O9具有优化的氧p带中心和最佳的催化活性.Ba3LaIr2O9是这类Ba3LnIr2O9结构当中最有潜力的产氧催化剂.
综上,本文通过DFT计算方法,研究了一系列低贵金属含量的Ba3LnIr2O9钙钛矿的电催化产氧活性,并筛选出了其中活性最优的Ba3LaIr2O9作为有潜力的OER电催化剂.这种通过DFT计算设计高效催化剂的方法有望加快实现各种新能源转换技术用催化剂的更新换代.

关键词: 镧系元素, 钙钛矿, 析氧反应, p带中心, 电催化剂

Abstract: The development of efficient oxygen evolution electrocatalysts with reduced noble metal uses is a critical challenge for the deployment of various advanced energy conversion technologies. Here, a series of lanthanide-contained 6H-perovskites with a formula of Ba3LnIr2O9 (Ln=lanthanides) are investigated as oxygen evolution electrocatalysts, whose active subunits (i.e., face-sharing IrO6 dimers) can be regulated by the lanthanides in terms of catalytic activity. By using density functional theory (DFT) calculations, we establish the theoretical trend in activity for Ba3LnIr2O9 6H-perovskites, the activity of which is correlated with the difference of adsorption free energy (△GO-△GOH) between O* and OH* reaction intermediates. We further establish a volcano curve between △GO-△GOH and the calculated O p-band center. Among the Ba3LnIr2O9 6H-perovskites, Ba3LaIr2O9 locates at the peak of volcano curve, and correspondingly is the most active electrocatalyst due to the optimal O p-band property.

Key words: Lanthanide, Perovskite, Oxygen evolution reaction, O p-band center, Electrocatalyst