Surface modification of NiCdO barrier layer in complex photoanodes and TiO2 protective coating for efficient and stabile water dissociation

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)803-812
Journal / PublicationJournal of Solid State Electrochemistry
Volume21
Issue number3
Publication statusPublished - 1 Mar 2017

Abstract

This work presents a follow-up research of our previously published work. Herein, the photocatalytic performance of a nanostructured CdZnO/NiCdO composite photoanode has been improved by intercalation of Cu catalyst atoms in the electron barrier layer of NiyCd1−yO surface by an ion exchange process. As a result, the photocurrent yield increased by 29 % at +1 V potential against Ag/AgCl. This phenomenon was tentatively attributed to the increased electron concentration and/or interaction of the Cu3d electrons with the mid-energy valence electrons. To the contrary, the introduction of Ag, Co, and Ni deteriorated the photocatalytic performance. The corrosion challenges were assessed during 50 cycles of voltammetry. The background of the degradation/photocorrosion was studied with SEM, EDX, and XPS analysis. To combat the photocorrosion, the photoanodes were coated with TiO2 protective nanolayers of different thickness. The results for the photocurrent stability at a constant potential of +1 V showed that 9 nm TiO2 coating improved the durability of the photoanode on account of a photocurrent decrease for about 50 %. XPS studies proved that the degradation/corrosion changes on the photoanode’s surface could be associated with an irreversible electrochemical oxidation of CdO into CdO2.

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