TY - JOUR

T1 - Tailoring the Photoelectrochemical Activity of TiO2 Electrodes by Multilayer Screen-Printing

AU - Günnemann, Carsten

AU - Curti, Mariano

AU - Eckert, J. Gerrit

AU - Schneider, Jenny

AU - Bahnemann, Detlef W.

N1 - Funding information: The authors thank Dipl.-Chem. Verena Becker for performing the AFM measurements. CG and JS acknowledge financial support from the Leibniz Universität Hannover within the program “Wege in die Forschung II”. MC is grateful to the Deutscher Akademischer Austauschdienst (DAAD) together with the Ministerio de Educación, Cultura, Ciencia y Tecnología (Argentina) for his ALEARG scholarship. This work was supported by Saint-Petersburg State University via a research Grant ID 32706707.

PY - 2019/12/18

Y1 - 2019/12/18

N2 - Screen-printing is a commonly used method for the preparation of photoelectrodes. Although previous studies have explored the effect of the number of printed layers on the efficiency of dye-sensitized solar cells, its interplay with the photoelectrocatalytic properties of the electrodes has rarely been examined. This study focuses on this issue by studying the photoelectrocatalytic oxidation of methanol over TiO 2 electrodes. Incident photon-to-current efficiencies reached 87 % at the optimal conditions of monochromatic (338 nm) irradiation of one-layer films at 0.2 V vs NHE. However, the irradiation wavelength and applied bias strongly influenced the relative behavior of the films. For instance, at 0.5 V and 327 nm irradiation, the one-layer electrode was 6 times more efficient than the four-layer one, while at 385 nm the four-layer electrode was 3.5 times more efficient. The results were explained on the basis of differing light absorption properties and charge carrier lifetimes. Modelling and quantification of the electron diffusion length (5.7 μm) helped to explain why the two-layer electrode (4.89 μm thick) showed the most consistent efficiencies across all conditions. Complementarily, transient absorption spectroscopy was used to correlate the thicknesses with charge carrier lifetimes. Electron transfer to FTO was apparent only for the thinner electrode. Our work shows that the optimization of photoelectrocatalytic processes should include the number of layers as a key variable.

AB - Screen-printing is a commonly used method for the preparation of photoelectrodes. Although previous studies have explored the effect of the number of printed layers on the efficiency of dye-sensitized solar cells, its interplay with the photoelectrocatalytic properties of the electrodes has rarely been examined. This study focuses on this issue by studying the photoelectrocatalytic oxidation of methanol over TiO 2 electrodes. Incident photon-to-current efficiencies reached 87 % at the optimal conditions of monochromatic (338 nm) irradiation of one-layer films at 0.2 V vs NHE. However, the irradiation wavelength and applied bias strongly influenced the relative behavior of the films. For instance, at 0.5 V and 327 nm irradiation, the one-layer electrode was 6 times more efficient than the four-layer one, while at 385 nm the four-layer electrode was 3.5 times more efficient. The results were explained on the basis of differing light absorption properties and charge carrier lifetimes. Modelling and quantification of the electron diffusion length (5.7 μm) helped to explain why the two-layer electrode (4.89 μm thick) showed the most consistent efficiencies across all conditions. Complementarily, transient absorption spectroscopy was used to correlate the thicknesses with charge carrier lifetimes. Electron transfer to FTO was apparent only for the thinner electrode. Our work shows that the optimization of photoelectrocatalytic processes should include the number of layers as a key variable.

KW - Photocatalysis

KW - Photoelectrocatalysis

KW - Photoelectrochemistry

KW - Solar energy conversion

KW - Titanium dioxide

UR - http://www.scopus.com/inward/record.url?scp=85076140174&partnerID=8YFLogxK

U2 - 10.1002/cctc.201901872

DO - 10.1002/cctc.201901872

M3 - Article

VL - 11

SP - 6439

EP - 6450

JO - CHEMCATCHEM

JF - CHEMCATCHEM

SN - 1867-3880

IS - 24

ER -