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An abnormal size effect enables ampere-level O2 electroreduction to hydrogen peroxide in neutral electrolytes
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2023-05-31 , DOI: 10.1039/d3ee00509g
Shan Ding 1 , Baokai Xia 1 , Ming Li 1 , Fengqian Lou 1 , Chi Cheng 2 , Tianqi Gao 1 , Yuxiang Zhang 1 , Kang Yang 1 , Lili Jiang 1 , Zhihao Nie 1 , Hongxin Guan 1 , Jingjing Duan 1 , Sheng Chen 1, 2
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The principle of size effect was noticed a century ago, and is now widely used to express the activity enhancement of a catalyst as a result of size decrease. However, there are exceptions. In this study we observe an abnormal size effect in oxygen electroreduction comprised of two- (to generate H2O2) and four-electron-transfer pathways (to generate H2O), where hydrogen peroxide (H2O2) is the target product. We have synthesized three zinc oxide nanoplate catalysts with different thicknesses (i.e., 87.7, 26.3 and 1.70 nm). In contrast to common expectation, the large-thickness zinc oxide plate (i.e., 87.7 nm) showed superior oxygen electroreduction activities with nearly 100% selectivity to H2O2 in the current density range of 0.05–1.3 A cm−2 in neutral electrolytes, while other size counterparts only demonstrated moderate activities. A mechanism study through theoretical calculations and in situ Raman spectra highlight the critical role of abnormal size effects in enabling oxygen electroreduction at elevated current densities, which can not only activate O2 but also stabilize the key reaction intermediate (*OOH) by shifting the d-band center toward the Femi level. Furthermore, the feasibility of the present technology is evaluated by following a rigorous techno-economic assessment protocol, showing a threshold current density of 0.2 A cm−2 for economically profitable manufacture, and the lowest H2O2 production cost (0.4 $ kg−1) achieved at 1.0 A cm−2.

中文翻译:

异常尺寸效应使安培级 O2 电还原为中性电解质中的过氧化氢

尺寸效应的原理在一个世纪前就已被注意到,现在被广泛用于表示由于尺寸减小而导致的催化剂活性增强。但是,也有例外。在这项研究中,我们观察到由两个(生成 H 2 O 2)和四个电子转移路径(生成 H 2 O)组成的氧电还原的异常尺寸效应,其中过氧化氢 (H 2 O 2 ) 是目标产品。我们合成了三种不同厚度(即87.7、26.3 和1.70 nm)的氧化锌纳米板催化剂。与普遍预期相反,大厚度氧化锌板(, 87.7 nm)在中性电解质中在0.05–1.3 A cm -2 的电流密度范围内表现出优异的氧电还原活性,对 H 2 O 2的选择性接近 100% ,而其他尺寸的对应物仅表现出中等活性。通过理论计算和原位拉曼光谱进行的机制研究突出了异常尺寸效应在提高电流密度下实现氧电还原中的关键作用,这不仅可以激活 O 2而且还通过将 d 波段中心移向 Femi 能级来稳定关键反应中间体 (*OOH)。此外,本技术的可行性通过遵循严格的技术经济评估协议进行评估,表明阈值电流密度为 0.2 A cm -2可实现经济盈利的制造,以及最低的 H 2 O 2生产成本(0.4 $ kg - 1 ) 在 1.0 A cm -2下实现。
更新日期:2023-06-02
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