TY - JOUR

T1 - Irreversible surface changes upon n-type doping

T2 - A photoelectrochemical study on rutile single crystals

AU - Haisch, C.

AU - Günnemann, C.

AU - Melchers, S.

AU - Fleisch, M.

AU - Schneider, J.

AU - Emeline, A.V.

AU - Bahnemann, D.W.

N1 - Funding information: The authors gratefully acknowledge financial support from the Federal Ministry of Education and Research BMBF (Project “DuaSol” No. 03SF0482C ), and the Global Research Laboratory program ( 2014K1A1A2041044 ) of Korea government (MSIP) through NRF. The present study was performed within the Project “Establishment of the Laboratory ‘Photoactive Nanocomposite Materials’” No. 14.Z50.31.0016 supported by a Mega-grant of the Government of the Russian Federation .

PY - 2018/8/1

Y1 - 2018/8/1

N2 - Single crystal wafers need to provide sufficient electrical conductivity to be employed in photoelectrochemical investigations. Usually, their defect concentrations and donor densities are too low to allow electrochemical measurements. Accordingly, TiO 2 rutile single crystal surfaces have to be n-type doped before their electrochemical activity can be evaluated. The doping itself, however, leads to irreversible changes in the surface morphology of the initially smooth crystalline surfaces. In this study, the effects of n-type doping and photoetching on TiO 2 rutile single crystal surfaces have been investigated. The photocatalytic and photoelectrochemical activities of the rutile single crystal wafers have been quantified by methanol photooxidation. The results indicate that n-type doping has different impacts on the employed rutile (100) and (110) surfaces. Subsequent photoetching is necessary to achieve comparable donor densities for both single crystal electrodes. Moreover, the rutile (100) surface is producing different product ratios depending on the applied external bias as compared with the rutile (110) surface for methanol and water oxidation.

AB - Single crystal wafers need to provide sufficient electrical conductivity to be employed in photoelectrochemical investigations. Usually, their defect concentrations and donor densities are too low to allow electrochemical measurements. Accordingly, TiO 2 rutile single crystal surfaces have to be n-type doped before their electrochemical activity can be evaluated. The doping itself, however, leads to irreversible changes in the surface morphology of the initially smooth crystalline surfaces. In this study, the effects of n-type doping and photoetching on TiO 2 rutile single crystal surfaces have been investigated. The photocatalytic and photoelectrochemical activities of the rutile single crystal wafers have been quantified by methanol photooxidation. The results indicate that n-type doping has different impacts on the employed rutile (100) and (110) surfaces. Subsequent photoetching is necessary to achieve comparable donor densities for both single crystal electrodes. Moreover, the rutile (100) surface is producing different product ratios depending on the applied external bias as compared with the rutile (110) surface for methanol and water oxidation.

KW - Methanol oxidation

KW - Photoelectrochemistry

KW - Photoetching

KW - Rutile

KW - Single crystal

KW - Titanium dioxide photocatalysis

KW - n-type doping

UR - http://www.scopus.com/inward/record.url?scp=85047642196&partnerID=8YFLogxK

U2 - 10.1016/j.electacta.2018.05.105

DO - 10.1016/j.electacta.2018.05.105

M3 - Article

VL - 280

SP - 278

EP - 289

JO - Electrochimica acta

JF - Electrochimica acta

SN - 0013-4686

ER -