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Dong, Y.* ; Han, Q.* ; Ma, K.* ; Song, F. ; Zheng, S.* ; Ding, Y.*

Study two kind different catalytic behaviors for K4H1.2[Co0.6(H2O)0.6SiW11.4O39.4]-cocatalyzed visible light driven water oxidation in pH 1–7 media.

J. Catal. 392, 29-38 (2020)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Efficient water oxidation remains a particular challenge in water splitting that calls for developing robust and economic water oxidation catalysts (WOCs), preferably based on earth-abundant transition metals. Herein, we report a robust and noble metal-free catalytical system using BiVO4 as an effective light-harvesting material, a cobalt-containing polyoxometalate K4H1.2[Co0.6(H2O)0.6SiW11.4O39.4] (1) as molecular cocatalyst, and NaIO3 as a sacrificial electron acceptor for visible-light-driven water oxidation in a wide pH range 1–7. The combination of 1 + BiVO4 samples gives better oxygen evolution activities than that of pristine BiVO4. A turnover number (TON) of 326.3, apparent quantum efficiency (AQE) of 10.0%, and an O2 yield of 21.8% are obtained under pH 4. This work investigates two kind different catalytic behaviors for 1-cocatalyzed visible light driven water oxidation at pH 1–7 media, which exhibits a pH-induced dynamic change on the catalytic active species. Catalytic behavior, XPS, SEM and TEM collectively testify that 1 remains intact during photocatalytic water oxidation under pH 4–5. Conversely, under pH 1–3 and 6–7, the heterogeneous CoOx originated from 1 is formed on the BiVO4 surface, which is responsible for the enhancement of BiVO4 photocatalytic activity. Our work uncovers the borderline between homogeneous and heterogeneous WOCs using a cobalt-based polyoxometalate at different pH media, which helps to the study of stability for polyoxometalates when semiconducting material is used as the light-harvesting material.
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Publication type Article: Journal article
Document type Scientific Article
Keywords Bivo 4 ; Catalytic Stability ; Cobalt-based Polyoxometalate ; Ph Effect ; Water Oxidation
ISSN (print) / ISBN 0021-9517
e-ISSN 1090-2694
Journal Journal of Catalysis
Quellenangaben Volume: 392, Issue: , Pages: 29-38 Article Number: , Supplement: ,
Publisher Elsevier
Publishing Place 525 B St, Ste 1900, San Diego, Ca 92101-4495 Usa
Reviewing status Peer reviewed
Institute(s) Helmholtz Pioneer Campus (HPC)
Grants National Natural Science Foundation of China