Valence State Modulation of Chromium in Selective Hydrogen Peroxide Production Electrocatalysts,ACS Applied Energy Materials

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Valence State Modulation of Chromium in Selective Hydrogen Peroxide Production Electrocatalysts
ACS Applied Energy Materials ( IF 5.4 ) Pub Date : 2021-09-13 , DOI: 10.1021/acsaem.1c02024
Huiyi Zhang ₁ , Zeming Wang ₁ , Zhe Wang ₂ , Liang Wang ₁ , Yong Wang ₁

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Hydrogen peroxide (H₂O₂) is a worthy chemical substance with comprehensive applications, but its practical industrial methods involve complex and energy-consuming procedures. Electrocatalytic oxygen reduction for the production of H₂O₂ is a flexible alternative strategy, which requires a low-cost catalyst with high activity and selectivity for the 2e^– ORR pathway. Here, we first present a straightforward and universal one-step hydrothermal method that directly combines Cr-ABIm with commercial carbon black (BP2000) to prepare H₂O₂ electrochemically with high selectivity and energy saving. A variety of characterization analyses display that the introduction of Cr-ABIm increases the number of defects and active sites and also enlarges the surface area of the catalyst for electrochemical reactions. Importantly, the valence state of Cr is changed (Cr³⁺ of Cr-ABIm converted to Cr⁵⁺) when Cr-ABIm anchors on BP2000, which accelerates the activity of the reduction reaction. The selectivity of the catalyst for H₂O₂ preparation is also determined by Koutecky–Levich analysis and rotating ring disk electrochemical tests. In a potential range of 0.2–0.7 V (vs reversible hydrogen electrode (RHE)), the electron transfer number of the Cr-ABIm@BP2000 catalyst is on the verge of 2.5, and the electrogenerated yield of H₂O₂ is 65%. In addition, its mass activity at 0.5 V is up to 7.56 A g^–1. Density functional theory (DFT) calculations clarify that suitable N, O coordination on the active surface of BP2000s acquires the changing capacity of the valence state of Cr, thereby regulating the adsorption of intermediate products and endowing it with superior H₂O₂ performance. It is believed that Cr-ABIm@BP2000 will be a viable electrocatalyst for sustainable in situ generation of H₂O₂ from oxygen.

中文翻译：

选择性过氧化氢生产电催化剂中铬的价态调节

过氧化氢（H ₂ O ₂）是一种应用广泛的有价值的化学物质，但其实际的工业方法涉及复杂且耗能的过程。用于生产 H ₂ O _{2 的}电催化氧还原是一种灵活的替代策略，它需要对 2e ^- ORR 途径具有高活性和选择性的低成本催化剂。在这里，我们首先提出了一种直接且通用的一步水热法，将 Cr-ABIm 与商业炭黑 (BP2000) 直接结合制备 H ₂ O ₂电化学具有高选择性和节能性。各种表征分析表明，Cr-ABIm 的引入增加了缺陷和活性位点的数量，也扩大了用于电化学反应的催化剂的表面积。重要的是，当 Cr-ABIm 锚定在 BP2000 上时，Cr的价态发生了变化（Cr -ABIm 的Cr ³⁺转化为 Cr ⁵⁺），这加速了还原反应的活性。催化剂对 H ₂ O ₂的选择性制备还通过 Koutecky-Levich 分析和旋转环盘电化学测试确定。在0.2-0.7 V（相对于可逆氢电极（RHE））的电位范围内，Cr-ABIm@BP2000催化剂的电子转移数接近2.5，H ₂ O ₂的电产率为65% . 此外，它在 0.5 V 时的质量活度高达 7.56 A g ^–1。密度泛函理论 (DFT) 计算阐明了 BP2000s 活性表面上合适的 N、O 配位获得了 Cr 价态的变化能力，从而调节了中间产物的吸附并赋予其优越的 H ₂ O ₂表现。据信，Cr-ABIm@BP2000 将成为一种可行的电催化剂，用于从氧气中可持续原位生成 H ₂ O ₂。

更新日期：2021-09-27

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