Mou Zhixing, Mu Yuewen, Liu Lijia, Cao Daili, Chen Shuai, Yan Wenjun, Zhou Haiqing, Chan Ting-Shan, Chang Lo-Yueh, Fan Xiujun
Institute of Crystalline Materials Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
Department of Chemistry, University of Western Ontario, London, N6A 5B7, Canada.
Small. 2024 Jul;20(29):e2400564. doi: 10.1002/smll.202400564. Epub 2024 Feb 17.
Developing efficient metal-free catalysts to directly synthesize hydrogen peroxide (HO) through a 2-electron (2e) oxygen reduction reaction (ORR) is crucial for substituting the traditional energy-intensive anthraquinone process. Here, in-plane topological defects enriched graphene with pentagon-S and pyrrolic-N coordination (SNC) is synthesized via the process of hydrothermal and nitridation. In SNC, pentagon-S and pyrrolic-N originating from thiourea precursor are covalently grafted onto the basal plane of the graphene framework, building unsymmetrical dumbbell-like S─C─N motifs, which effectively modulates atomic and electronic structures of graphene. The SNC catalyst delivers ultrahigh HO productivity of 8.1, 7.3, and 3.9 mol g h in alkaline, neutral, and acidic electrolytes, respectively, together with long-term operational stability in pH-universal electrolytes, outperforming most reported carbon catalysts. Theoretical calculations further unveil that defective S─C─N motifs efficiently optimize the binding strength to OOH intermediate and substantially diminish the kinetic barrier for reducing O to HO, thereby promoting the intrinsic activity of 2e-ORR.
开发高效的无金属催化剂以通过2电子（2e）氧还原反应（ORR）直接合成过氧化氢（H₂O₂）对于替代传统的能源密集型蒽醌工艺至关重要。在此，通过水热和氮化过程合成了具有五边形-S和吡咯-N配位（SNC）的面内拓扑缺陷富集石墨烯。在SNC中，源自硫脲前体的五边形-S和吡咯-N共价接枝到石墨烯框架的基面上，构建不对称哑铃状S─C─N基序，有效调节石墨烯的原子和电子结构。SNC催化剂在碱性、中性和酸性电解质中分别具有8.1、7.3和3.9 mol g⁻¹ h⁻¹的超高H₂O₂产率，以及在pH通用电解质中的长期运行稳定性，优于大多数已报道的碳催化剂。理论计算进一步揭示，有缺陷的S─C─N基序有效优化了与OOH中间体的结合强度，并大幅降低了将O还原为H₂O₂的动力学势垒，从而促进了2e-ORR的本征活性。
