Wei Chao, Sun Shengnan, Mandler Daniel, Wang Xun, Qiao Shi Zhang, Xu Zhichuan J
School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
Chem Soc Rev. 2019 May 7;48(9):2518-2534. doi: 10.1039/c8cs00848e.
Great attention has been recently drawn to metal oxide electrocatalysts for electrocatalysis-based energy storage and conversion devices. To find the optimal electrocatalyst, a prerequisite is an activity metric that reasonably evaluates the intrinsic electrocatalytic activity of a particular catalyst. The intrinsic activity is commonly defined as the specific activity which is the current per unit catalyst surface area. Thus, the precise assessment of intrinsic activity highly depends on the reliable measurement of catalyst surface area, which calls for the knowledge of experimental approaches for determining the surface areas of metal oxide electrocatalysts. This tutorial review aims to summarize and analyze the approaches for measuring the surface areas of metal oxide electrocatalysts for evaluating and comparing their intrinsic electrocatalytic activities. We start by comparing the popular metrics for activity estimation and highlighting the importance of surface-area-normalized activity (i.e. specific activity) for intrinsic chemistry analysis. Second, we provide some general guidelines for experimentally measuring the electrochemically active surface area (ECSA). Third, we review the methods for the surface area measurement of metal oxide electrocatalysts. The detailed procedure for each method is explicitly described to provide a step-by-step manual that guides researchers to perform the measurement; the rationales and uncertainties for each method are discussed to help readers justify the reliable assessment of surface area. Next, we give our recommendations on selecting a rational experimental approach for the surface area measurement of a particular metal oxide electrocatalyst. Lastly, we discuss the future challenges of ECSA measurement and present an exemplary novel ECSA technique.
最近，基于电催化的能量存储和转换装置的金属氧化物电催化剂受到了极大关注。为了找到最佳的电催化剂，一个先决条件是要有一个能合理评估特定催化剂本征电催化活性的活性指标。本征活性通常定义为比活性，即单位催化剂表面积的电流。因此，本征活性的精确评估高度依赖于催化剂表面积的可靠测量，这就需要了解测定金属氧化物电催化剂表面积的实验方法。本教程综述旨在总结和分析用于测量金属氧化物电催化剂表面积的方法，以评估和比较它们的本征电催化活性。我们首先比较用于活性估计的常用指标，并强调表面积归一化活性（即比活性）对本征化学分析的重要性。其次，我们提供一些实验测量电化学活性表面积（ECSA）的一般指导原则。第三，我们综述金属氧化物电催化剂表面积测量的方法。详细描述了每种方法的具体步骤，以提供一份指导研究人员进行测量的分步手册；讨论了每种方法的原理和不确定性，以帮助读者证明表面积可靠评估的合理性。接下来，我们就为特定金属氧化物电催化剂的表面积测量选择合理的实验方法给出建议。最后，我们讨论了ECSA测量未来面临的挑战，并介绍了一种示例性的新型ECSA技术。
