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{"title":"Selective H<sub>2</sub>O<sub>2</sub> Electrosynthesisnover Defective Carbon from Electrochemical Etching of Molybdenum Carbide","authors":"Chunyu Zhang (118320), Chan Wu (664186), Li Wang (15202), Guozhu Liu (1295691)","doi":"10.1021/acsami.2c15467.s001","DOIUrl":"https://doi.org/10.1021/acsami.2c15467.s001","url":null,"abstract":"The controllable synthesis of specific defective carbonncatalystsnis crucial for two-electron oxygen reduction reaction (2e<sup>–</sup> ORR) to generate H<sub>2</sub>O<sub>2</sub> due to the great potentialnapplications. Herein, the defective carbon catalysts (Mo-CDC-ns) werenprepared by an electrochemical activation (ECA) method with Mo<sub>2</sub>C/C as a parent. Electrochemical cyclic voltammetry curves,nX-ray photoelectron spectroscopy, inductively coupled plasma-massnspectrometry, scanning electron microscopy, and high-resolution transmissionnelectron microscopy confirm the evolution process of a defective carbonnstructure from the Mo<sub>2</sub>C phase in which Mo species are firstnoxidized to Mo<sup>6+</sup> species and then the latter are dissolvedninto the solution and defective carbon is simultaneously formed. Ramannand electron paramagnetic resonance spectra reveal that the defectntypes in Mo-CDC-ns are the edge defect and vacancy defect sites. Comparednwith the parent Mo<sub>2</sub>C/C, Mo-CDC-ns exhibit gradually increasednkinetic current density and selectivity for H<sub>2</sub>O<sub>2</sub> generation with an extension of activation cycles from 10 (Mo-CDC-10)nto 30 (Mo-CDC-30). Over Mo-CDC-30, a kinetic current density of 19.4nmA cm<sup>–2</sup> and a selectivity close to 90% in 0.1 MnKOH solution were achieved, as well as good stability for H<sub>2</sub>O<sub>2</sub> production in an extended test up to 12 h in an H-cell.nGraphene planes and Stone Wales 5757-carbon were constructed as basicnmodels for density functional theory calculations. It revealed thatnthe obtained defective structure after the removal of Mo atoms containsnthe double vacancy at the edge of graphene (Edge-DVC) and the topologicalndefect on the plane of 5757-carbon (5757C-D), which show more moderatenreaction free energy for forming *OOH and smaller energy barrier ofn2e<sup>–</sup> ORR.","PeriodicalId":522803,"journal":{"name":"Figshare","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1753-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147904009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}