Adsorption and photocatalytic splitting of water on graphitic carbon nitride

  • Graphitic carbon nitride, g-C₃N₄, is a promising organic photo-catalyst for a variety of redox reactions. In order to improve its efficiency in a systematic manner, however, a fundamental understanding of the microscopic interaction between catalyst, reactants and products is crucial. Here we present a systematic study of water adsorption on g-C₃N₄ by means of density functional theory and the density functional based tight-binding method as a prerequisite for understanding photocatalytic water splitting. We then analyze this prototypical redox reaction on the basis of a thermodynamic model providing an estimate of the overpotential for both water oxidation and H⁺ reduction. While the latter is found to occur readily upon irradiation with visible light, we derive a prohibitive overpotential of 1.56 eV for the water oxidation half reaction, comparing well with the experimental finding that in contrast to H₂ production O₂ evolution is only possible in the presence of oxidation cocatalysts.

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Author:Jonas Wirth, Rainer Neumann, Markus AntoniettiORCiDGND, Peter SaalfrankORCiDGND
ISSN:1463-9076 (print)
ISSN:1463-9084 (online)
Parent Title (English):physical chemistry, chemical physics : PCCP
Subtitle (English):a combined first principles and semiempirical study
Document Type:Article
Date of first Publication:2014/06/25
Year of Completion:2014
Publishing Institution:Universität Potsdam
Release Date:2015/04/28
Tag:augmented-wave method; hydrogen; initio molecular-dynamics; oxidation; photooxidation; reduction; simulations; tight-binding; transition; visible-light
First Page:15917
Last Page:15926
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Peer Review:Referiert
Publication Way:Open Access
Licence (English):License LogoCreative Commons - Attribution 3.0 unported
Notes extern:Zweitveröffentlichung als Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe ; 172