Townsend William J V, López-Alcalá Diego, Bird Matthew A, Jordan Jack W, Rance Graham A, Biskupek Johannes, Kaiser Ute, Baldoví José J, Walsh Darren A, Johnson Lee R, Khlobystov Andrei N, Newton Graham N
Nottingham Applied Materials and Interfaces (NAMI) Group, GSK Carbon Neutral Laboratories for Sustainable Chemistry, School of Chemistry, University of Nottingham, Nottingham, UK.
School of Chemistry, University of Nottingham, Nottingham, UK.
Nat Commun. 2025 May 14;16(1):4460. doi: 10.1038/s41467-025-59740-z.
Designing inexpensive, sustainable, and high-performance oxygen-evolution reaction (OER) electrocatalysts is one of the largest obstacles hindering the development of new electrolyzers. Carbon-coated metal/metal oxide (nano)particles have been used in such applications, but the role played by the carbon coatings is poorly understood. Here, we use a carbon-coated catalyst comprising metal-oxide nanoparticles encapsulated within single-walled carbon nanotubes (SWNTs), to study the effects of carbon coatings on catalytic performance. Electrolyte access to the encapsulated metal oxides is shut off by plugging the SWNT ends with size-matched fullerenes. Our results reveal that the catalytic activity of the composite rivals that of the metal oxide, despite the fact that the metal oxides cannot access the bulk electrolyte. Moreover, the rate-determining step (RDS) of the OER matches that measured at empty SWNTs, indicating that electrocatalysis occurs on the carbon surface. Synergism between the encapsulated metal oxide and carbon coating was explored using electrochemical Raman spectroscopy and computational analysis, revealing that charge transfer from the carbon host to the metal oxide is key to the high electrocatalytic activity of carbon in this system; decreasing electron density on the carbon surface facilitates binding of OH, accelerating the rate of the OER on the carbon surface.
设计价格低廉、可持续且高性能的析氧反应（OER）电催化剂是阻碍新型电解槽发展的最大障碍之一。碳包覆的金属/金属氧化物（纳米）颗粒已用于此类应用，但碳涂层所起的作用却鲜为人知。在此，我们使用一种由封装在单壁碳纳米管（SWNTs）内的金属氧化物纳米颗粒组成的碳包覆催化剂，来研究碳涂层对催化性能的影响。通过用尺寸匹配的富勒烯堵塞SWNT末端，阻止电解质接触被封装的金属氧化物。我们的结果表明，尽管金属氧化物无法接触本体电解质，但该复合材料的催化活性与金属氧化物相当。此外，OER的速率决定步骤（RDS）与在空SWNTs上测得的一致，表明电催化发生在碳表面。利用电化学拉曼光谱和计算分析探究了被封装的金属氧化物与碳涂层之间的协同作用，结果表明从碳主体到金属氧化物的电荷转移是该体系中碳具有高电催化活性的关键；降低碳表面的电子密度有助于OH的吸附，加快碳表面OER的速率。
