Photoelectrocatalytic H2 evolution in water with molecular catalysts immobilised on p-Si via a stabilising mesoporous TiO2 interlayer. Issue 7 (31st May 2017)

• Record Type: Journal Article
• Authors: Leung, Jane J.; Warnan, Julien; Nam, Dong Heon; Zhang, Jenny Z.; Willkomm, Janina; Reisner, Erwin
• Is Part Of: Chemical science. Volume 8:Issue 7(2017)
• Page Start: 5172
• Page End: 5180
• Publication Date: 2017-05-31
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7sc01277b
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : A versatile platform for the immobilisation of molecular catalysts on a readily-prepared Si photocathode with a mesoporous TiO2 layer is reported. 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 × 10 3 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.