N修饰碳层覆载型Co_(9)S_(8)纳米颗粒用于高效电催化合成过氧化氢的研究

Study on N-modified carbon coated Co_(9)S_(8) nanoparticles for efficient electrocatalytic H_(2)O_(2) production

电催化技术中,二电子氧还原反应(2e^(-)-ORR)是一种可用于直接合成过氧化氢(H_(2)O_(2))的绿色电化学合成方法。由于能耗低、操作简易等优点,已逐步成为可替代传统工业生产蒽醌法的新型制备技术。目前该研究多数集中于单原子级或Pt、Pd基等贵金属材料,对于非贵金属复合材料的相关报道较少。基于此,本文通过一步热氨还原法,成功制备了N掺杂下的覆载在碳层表面的Co_(9)S_(8)纳米颗粒电催化剂(Co_(9)S_(8)@NC),通过高分辨率透射电镜(HRTEM)等表征证明了覆载在碳层表面的Co_(9)S_(8)纳米颗粒结构的成功合成。电化学测试结果表明,在0.1 M的KOH电解液中,在较为宽泛的电压窗口范围内,该催化剂的H_(2)O_(2)选择性(Selectivity)最高达到95%,电子转移数(n)为2.09左右,表明该催化剂有效地促进了对于2e^(-)-ORR优异的催化性能。本文为设计低成本、高效能的碳基复合材料用于碱性条件下电催化制备H_(2)O_(2)的研究提供了较为新颖和有价值的理论依据。

As one of the electrocatalysis technology,electrocatalytic two-electron oxygen reduction reaction(2e^(-)-ORR)is an ecofriendly electrochemical synthesis method which can be used to synthesize hydrogen peroxide(H_(2)O_(2))directly.Because of its low cost and easy operation,it has gradually become a new synthetic route that replaces the traditional industrial production of anthraquinone.At present,most of the research focuses on monatomic or noble metal materials(Pt,Pd),and there are few reports on non-noble metal composites.Based on this,this paper successfully prepared the Co_(9)S_(8)@NC electrocatalyst that Co_(9)S_(8)nanoparticles loaded on the Ndoped carbon layer surface by one-step hot-ammonia annealing method.The successful synthesis of Co_(9)S_(8)nanoparticle structure on the surface of carbon layer was proved by high resolution transmission electron microscope(HRTEM)and other characterizations.The electrochemical test results showed that in 0.1 M KOH electrolyte,within a wide voltage range,the H_(2)O_(2)selectivity of the catalyst reached maximum 95%with the electron transfer number(n)was about 2.09,which indicates that the Co_(9)S_(8)@NC effectively promoted the catalytic performance for 2e^(-)-ORR as an excellent electrocatalyst.Furthermore,this paper provides a novel and valuable theoretical basis for the design of low-cost and high-efficiency carbon matrix composites for the research of electrocatalytic preparation of H_(2)O_(2)under alkaline conditions.