材料科学
催化作用
法拉第效率
可逆氢电极
氧气
析氧
电催化剂
质子化
过氧化氢
无机化学
选择性
电解质
化学工程
电化学
离子
物理化学
电极
工程类
参比电极
有机化学
化学
作者
Ruijie Gao,Lun Pan,Zhengwen Li,Chengxiang Shi,Yunduo Yao,Xiangwen Zhang,Ji‐Jun Zou
标识
DOI:10.1002/adfm.201910539
摘要
Abstract Hydrogen peroxide is a highly valuable chemical, and electrocatalytic oxygen reduction towards H 2 O 2 offers an alternative method for safe on‐site applications. Generally, low‐cost hematite (α‐Fe 2 O 3 ) is not recognized as an efficient electrocatalyst because of its inert nature, but it is herein reported that α‐Fe 2 O 3 can be endowed with high catalytic activity and selectivity via the engineering of facets and oxygen vacancies. Density‐functional theory (DFT)calculations predict that the {001} facet is intrinsically selective for H 2 O 2 production, and that oxygen vacancies can trigger the high activity, providing sites for O 2 adsorption and protonation, stabilizing the *OOH intermediate, and preventing cleavage of the OO bond. The synthesized oxygen‐defective α‐Fe 2 O 3 single crystals with exposed {001} facets achieve high selectivities for H 2 O 2 of >90%, >88%, and >95% in weakly acidic, neutral, and alkaline electrolytes, respectively, and the H 2 O 2 production rate reaches 454 mmol g −1 cat h −1 at 0.1 V versus RHE under alkaline conditions. In an anion exchange membrane fuel cell, a maximum H 2 O 2 production of 546.8 mmol L −1 with a high Faradaic efficiency of 80.5% is achieved. Thus, this work details a low‐cost catalyst feasible for H 2 O 2 synthesis, and highlights the feasibility of theoretical catalyst design for practical applications.
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