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Carbon Thin-Layer-Protected Active Sites for ZIF-8-DerivednNitrogen-Enriched Carbon Frameworks/Expanded Graphite as Metal-FreenCatalysts for Oxygen Reduction in Acidic Media zif -8衍生的富氮碳骨架/膨胀石墨的薄层保护活性位点作为酸性介质中氧还原的无金属催化剂

Figshare Pub Date : 2018-08-24 DOI: 10.1021/acs.chemmater.8b02275.s001

Hun Chen (5682530), Shijie You (703364), Yuanyuan Ma (280707), Chunyue Zhang (1945735), Baojian Jing (5682533), Zhuang Cai (4178719), Bo Tang (23472), Nanqi Ren (1785790), Jinlong Zou (2092303)

{"title":"Carbon Thin-Layer-Protected Active Sites for ZIF-8-DerivednNitrogen-Enriched Carbon Frameworks/Expanded Graphite as Metal-FreenCatalysts for Oxygen Reduction in Acidic Media","authors":"Hun Chen (5682530), Shijie You (703364), Yuanyuan Ma (280707), Chunyue Zhang (1945735), Baojian Jing (5682533), Zhuang Cai (4178719), Bo Tang (23472), Nanqi Ren (1785790), Jinlong Zou (2092303)","doi":"10.1021/acs.chemmater.8b02275.s001","DOIUrl":"https://doi.org/10.1021/acs.chemmater.8b02275.s001","url":null,"abstract":"Generally,nsluggish oxygen reduction reaction (ORR) kinetics onncathode limits the practical application of the direct methanol fuelncell (DMFC). In this study, zeolitic-imidazolate-framework-8 (ZIF-8)-derivedncarbon is used to decorate expanded graphite (EG) to prepare a nitrogen-richnporous metal-free carbon framework (Z8-NCF-P/EGs) as catalyst fornORR in DMFC. Through use of a simple one-pot method, ZIF-8 is firmlynanchored on EG to obtain the ZIF-8/EG precursor via a polyvinypyrrolidonen(PVP)-assisted route. After carbonization and acid etching, the formednmicromesoporous structure contributes to the high specific surfacenarea and well-distributed porous 3D bulk networks of Z8-NCF-P/EGs,nwhich provide short diffusion paths for rapid oxygen and mass transfernkinetics. Z8-NCF-P/EG-10 (ZIF-8/EG weight ratio of 10) exhibits activityncomparable to that of commercial Pt/C (10 wt %) and methanol tolerancenand stability much higher than those of Pt/C in acidic electrolyte.nEG contributes to the uniform distribution and confined growth ofnZ8-NCF and the high electrical conductivity. PVP-derived carbon thinnlayer protects the deterioration of active sites. Pyridine N and graphiticnN provide the highly active and fully accessible active sites to enhancenthe onset potential (0.663 V vs SCE) and charge transfer efficiencynfor ORR to promote the 4e<sup>–</sup> process for Z8-NCF-P/EG-10.nMoreover, sufficient oxygen groups and N species maximize the exposurenof catalytic centers for O<sub>2</sub> chemisorption and reductionnto improve activity and methanol resistance. Therefore, metal-freenZ8-NCF-P/EGs provide the reference and appreciable prospect for othernZIF-derived catalysts for enhancing ORR activity.","PeriodicalId":522155,"journal":{"name":"Figshare","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147892572","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}

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