A robust ALD-protected silicon-based hybrid photoelectrode for hydrogen evolution under aqueous conditions. Issue 16 (21st March 2019)

• Record Type: Journal Article
• Authors: Chandrasekaran, Soundarrajan; Kaeffer, Nicolas; Cagnon, Laurent; Aldakov, Dmitry; Fize, Jennifer; Nonglaton, Guillaume; Baleras, François; Mailley, Pascal; Artero, Vincent
• Is Part Of: Chemical science. Volume 10:Issue 16(2019)
• Page Start: 4469
• Page End: 4475
• Publication Date: 2019-03-21
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc05006f
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Hybrid systems combining molecular catalysts with inorganic materials is a promising solution towards cheap yet efficient and stable photoelectrochemical hydrogen production. Abstract : Hydrogen production through direct sunlight-driven water splitting in photo-electrochemical cells (PECs) is a promising solution for energy sourcing. PECs need to fulfill three criteria: sustainability, cost-effectiveness and stability. Here we report an efficient and stable photocathode platform for H2 evolution based on Earth-abundant elements. A p-type silicon surface was protected by atomic layer deposition (ALD) with a 15 nm TiO2 layer, on top of which a 300 nm mesoporous TiO2 layer was spin-coated. The cobalt diimine–dioxime molecular catalyst was covalently grafted onto TiO2 through phosphonate anchors and an additional 0.2 nm ALD-TiO2 layer was applied for stabilization. This assembly catalyzes water reduction into H2 in phosphate buffer (pH 7) with an onset potential of +0.47 V vs. RHE. The resulting current density is −1.3 ± 0.1 mA cm −2 at 0 V vs. RHE under AM 1.5 solar irradiation, corresponding to a turnover number of 260 per hour of operation and a turnover frequency of 0.071 s −1 .