Solar H2 generation in water with a CuCrO2 photocathode modified with an organic dye and molecular Ni catalyst

• Published in: Chemical science (Cambridge) 2018, Vol.9 (6), p.1439-1447
• Main Authors: Creissen, Charles E, Warnan, Julien, Reisner, Erwin
• Format: Article
• Language: English
• Subjects: Aqueous electrolytes; Catalysis; Catalysts; Chemistry; Dyes; Electrolytic cells; Fuel production; Hydrogen production; Nickel oxides; P-type semiconductors; Photocathodes; Photoelectric effect; Photoelectric emission; Photoelectrolysis; Photovoltaic cells; Semiconductors
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c7sc04476c

Dye-sensitised photoelectrochemical (DSPEC) cells have emerged in recent years as a route to solar fuel production. However, fuel-forming photocathodes are presently limited by photo-corrodible narrow band gap semiconductors or the small range of available wide bandgap p-type semiconductors such as NiO that display low performance with dyes. Here, we introduce CuCrO2 as a suitable p-type semiconductor for visible light-driven H2 generation upon co-immobilisation of a phosphonated diketopyrrolopyrrole dye with a Ni-bis(diphosphine) catalyst. The hybrid CuCrO2 photocathode displays an early photocurrent onset potential of +0.75 V vs. RHE and delivers a photocurrent of 15 μA cm−2 at 0.0 V vs. RHE in pH 3 aqueous electrolyte solution under UV-filtered simulated solar irradiation. Controlled potential photoelectrolysis at 0.0 V vs. RHE shows good stability and yields a Ni catalyst-based turnover number of 126 ± 13 towards H2 after 2 h. This precious metal-free system outperforms an analogous NiO|dye/catalyst assembly and therefore highlights the benefits of using CuCrO2 as a novel material for DSPEC applications.