Li Sifan, Du Shiwen, Li Jiansheng, Fan Wenjun, Yang Yang, Zhao Peng, Zhu Haotian, You Wansheng, Sang Xiaojing, Zhang Fuxiang
School of Chemistry and Chemical Engineering, Liaoning Normal University Dalian 116029 Liaoning China
Department of Biochemical Engineering, Chaoyang Normal University Chaoyang 122000 Liaoning China.
Chem Sci. 2025 Jun 2. doi: 10.1039/d5sc03069b.
Identifying and tailoring active sulfur configurations in heteroatom-doped carbon electrocatalysts for the selective 2e oxygen reduction reaction (ORR) pathway remains a significant challenge. Here we designed and synthesized sulfur-doped reduced graphene oxide electrocatalysts containing C-S and C-SO moieties (denoted as S RGO, = 1, 10, 20) for promising ORR into hydrogen peroxide (HO). The optimized SRGO catalyst exhibits unexpected HO selectivity of 90% across a wide voltage range of 0.10-0.65 V, accompanied with excellent long-term stability (40 h) in an alkaline flow cell with 90.5% HO faradaic efficiency at an industrial current density of 300 mA cm. Theoretical and experimental analyses integrally reveal and identify the C-S and C-SO groups as the main active sites in the carbon-based catalyst. Specifically, the C-S group is found to favor the formation of OOH*, while the C-SO group not only facilitates the desorption of OOH* but also modulates interfacial mass transport kinetics, thereby creating a favorable microenvironment for HO generation.
在杂原子掺杂的碳电催化剂中识别并定制用于选择性2e氧还原反应（ORR）途径的活性硫构型仍然是一项重大挑战。在此，我们设计并合成了含有C-S和C-SO基团（表示为SRGO， = 1, 10, 20）的硫掺杂还原氧化石墨烯电催化剂，用于将有前景的ORR转化为过氧化氢（HO）。优化后的SRGO催化剂在0.10 - 0.65 V的宽电压范围内展现出意想不到的90%的HO选择性，在碱性流动电池中具有出色的长期稳定性（40小时），在300 mA cm的工业电流密度下HO法拉第效率为90.5%。理论和实验分析全面揭示并确定了C-S和C-SO基团是碳基催化剂中的主要活性位点。具体而言，发现C-S基团有利于形成OOH*，而C-SO基团不仅促进OOH*的解吸，还调节界面传质动力学，从而为HO的生成创造了有利的微环境。
