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Photoelectrocatalytic H$_2$ evolution in water with molecular catalysts immobilised on p-Si $\textit{via}$ a stabilising mesoporous TiO$_2$ interlayer

Published version
Peer-reviewed

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Authors

Leung, J 
Warnan, J 
Nam, D 

Abstract

The development of photoelectrodes capable of light-driven hydrogen evolution from water is an important approach for the storage of solar energy in the form of a chemical energy carrier. However, molecular catalyst-based photocathodes remain scarcely reported and typically suffer from low efficiencies and/or stabilities due to inadequate strategies for interfacing the molecular component with the light-harvesting material. In this study, we report the straightforward preparation of a p-silicon|mesoporous titania|molecular catalyst photocathode assembly that is active towards proton reduction in aqueous media with an onset potential of +0.4 V vs. RHE. The mesoporous TiO2 scaffold acts as an electron shuttle between the silicon and the catalyst, while also stabilising the silicon from passivation and enabling a high loading of molecular catalysts (>30 nmol (geometrical cm)−2). When a Ni bis(diphosphine)-based catalyst is anchored on the surface of the electrode, a high turnover number of ~1 x 103 was obtained from photoelectrolysis under UV-filtered simulated solar irradiation at 1 Sun after 24 h at pH 4.5. Notwithstanding its aptitude for molecular catalyst immobilisation, the p-Si|TiO2 photoelectrode showed great versatility towards different catalysts and pH conditions, with photoelectrocatalytic H2 generation also being achieved with platinum and a hydrogenase as catalyst, highlighting the flexible platform it represents for many potential reductive catalysis transformations.

Description

Keywords

0306 Physical Chemistry (incl. Structural), 0907 Environmental Engineering, 0303 Macromolecular and Materials Chemistry

Journal Title

Chemical Science

Conference Name

Journal ISSN

2041-6520
2041-6539

Volume Title

Publisher

Royal Society of Chemistry
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/K010220/1)
Christian Doppler Forschungsgesellschaft (unknown)
European Research Council (682833)
We gratefully acknowledge support from the Woolf Fisher Trust in New Zealand, the Christian Doppler Research Association (Austrian Federal Ministry of Science, Research and Economy and National Foundation for Research, Technology and Development), the OMV Group, an ERC Consolidator Grant ‘MatEnSAP’ (682833), and the National Research Foundation via the Creative Research Initiative Center (Republic of Korea, Grant No. NRF-2015R1A3A2066191).