The effects of copper doping on photocatalytic activity at (101) planes of anatase TiO2: A theoretical study

[Display omitted] •We present DFT simulation of H2O on pristine and Cu doped a-TiO2 (101) surface.•On both pristine and Cu doped surfaces, associative water adsorption is favourable.•Cu’s disperse configuration suggests formation of secondary CuO is unfavourable.•The calculations with GGA and GGA+vd...

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Bibliographic Details
Published in:Applied surface science 2016-11, Vol.387, p.682-689
Main Authors: Assadi, M. Hussein N., Hanaor, Dorian A.H.
Format: Article
Language:English
Subjects:
Ab-initio
Anatase
Catalytic activity
Chemical Sciences
Condensed Matter
Copper
Copper dopant
Doping
Engineering Sciences
Material chemistry
Materials
Materials Science
Photocatalysis
Physics
Planes
Surface chemistry
TiO2
Titanium dioxide
Water adsorption
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Summary:[Display omitted] •We present DFT simulation of H2O on pristine and Cu doped a-TiO2 (101) surface.•On both pristine and Cu doped surfaces, associative water adsorption is favourable.•Cu’s disperse configuration suggests formation of secondary CuO is unfavourable.•The calculations with GGA and GGA+vdW functionals render the same trends. Copper dopants are varyingly reported to enhance photocatalytic activity at titanium dioxide surfaces through uncertain mechanisms. In order to interpret how copper doping might alter the performance of titanium dioxide photocatalysts in aqueous media we applied density functional theory methods to simulate surface units of doped anatase (101) planes. By including van der Waals interactions, we consider the energetics of adsorbed water at anatase surfaces in pristine and copper doped systems. Simulation results indicate that copper dopant at anatase (101) surfaces is most stable in a 2+ oxidation state and a disperse configuration, suggesting the formation of secondary CuO phases is energetically unfavourable. In agreement with previous reports, water at the studied surface is predicted to exhibit molecular adsorption with this tendency slightly enhanced by copper. Results imply that the enhancement of photoactivity at anatase surfaces through Cu doping is more likely to arise from electronic interactions mediated by charge transfer and inter-bandgap states increasing photoexcitation and extending surface-hole lifetimes rather than through the increased density of adsorbed hydroxyl groups.
ISSN:0169-4332
1873-5584
DOI:10.1016/j.apsusc.2016.06.178