{"title":"How cations catalyse the hydrogenation of graphene vacancies","authors":"E. Santos","doi":"10.1016/j.electacta.2024.144532","DOIUrl":null,"url":null,"abstract":"<div><p>In alkaline solutions hydrogen adsorption involves the splitting of a water molecule, which can be catalysed by the presence of cations. We have analysed the adsorption processes from a water molecule approaching the surface of a graphene bilayer containing a vacancy, both in the presence and in the absence of cations (Na<sup>+</sup>, <em>K</em><sup>+</sup> and Mg<sup>2+</sup>) by quantum molecular dynamics using DFT based tight-binding. A cation near the interface induces a region with positive excess charge in its solvation shell, which facilitates the orientation of the reacting water molecule with the hydrogen towards the surface. This concerted mechanism catalyses the hydrogenation and stabilizes the resulting hydroxyl. Therefore in the presence of cations the hydrogen evolution reaction occurs spontaneously at less negative charges than in the absence. Thus our investigations suggest a detailed scenario for the catalytic effect of cations both on the spatial and temporal nano-scale.</p></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":5.5000,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0013468624007722/pdfft?md5=625a2e6c1a3ae9482fe568102a1fcc26&pid=1-s2.0-S0013468624007722-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Electrochimica Acta","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0013468624007722","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ELECTROCHEMISTRY","Score":null,"Total":0}
引用次数: 0
Abstract
In alkaline solutions hydrogen adsorption involves the splitting of a water molecule, which can be catalysed by the presence of cations. We have analysed the adsorption processes from a water molecule approaching the surface of a graphene bilayer containing a vacancy, both in the presence and in the absence of cations (Na+, K+ and Mg2+) by quantum molecular dynamics using DFT based tight-binding. A cation near the interface induces a region with positive excess charge in its solvation shell, which facilitates the orientation of the reacting water molecule with the hydrogen towards the surface. This concerted mechanism catalyses the hydrogenation and stabilizes the resulting hydroxyl. Therefore in the presence of cations the hydrogen evolution reaction occurs spontaneously at less negative charges than in the absence. Thus our investigations suggest a detailed scenario for the catalytic effect of cations both on the spatial and temporal nano-scale.
期刊介绍:
Electrochimica Acta is an international journal. It is intended for the publication of both original work and reviews in the field of electrochemistry. Electrochemistry should be interpreted to mean any of the research fields covered by the Divisions of the International Society of Electrochemistry listed below, as well as emerging scientific domains covered by ISE New Topics Committee.