Hydrogen Production at a NiO Photocathode Based on a Ruthenium Dye-Cobalt Diimine Dioxime Catalyst Assembly: Insights from Advanced Spectroscopy and Post-operando Characterization

Emmanouil Giannoudis (1) , Sébastian Bold (1, 2, 3) , Caroline Müller (2, 3, 4) , Alexander Schwab (2) , Jakob Bruhnke (2) , Nicolas Queyriaux (1) , Corinne Gablin (5) , Didier Léonard (5) , Christine Saint-Pierre (6) , Didier Gasparutto (6) , Dmitry Aldakov (6) , Stephan Kupfer (2) , Vincent Artero (1) , Benjamin Dietzek (2, 3, 4) , Murielle Chavarot-Kerlidou (1)

1 SolHyCat - Solar fuels, hydrogen and catalysis
2 Institute of Physical Chemistry and Abbe Center of Photonics
3 Leibniz IPHT - Department Functional Interfaces, Leibniz Institute of Photonic Technology
4 Center for Energy and Environmental Chemistry (CEEC Jena)
5 ISA - Institut des Sciences Analytiques
6 STEP - Synthèse, Structure et Propriétés de Matériaux Fonctionnels

The production of hydrogen by efficient, low-cost, and integrated photoelectrochemical water splitting processes represents an important target for the ecological transition. This challenge can be addressed thanks to bioinspired chemistry and artificial photosynthesis approaches by designing dye-sensitized photocathodes for hydrogen production, incorporating bioinspired first-row transition metal-based catalysts. The present work r describes the preparation and photoelectrochemical characterization of a NiO photocathode sensitized with a phosphonate-derivatized ruthenium tris-diimine photosensitizer covalently linked to a cobalt diimine dioxime hydrogen-evolving catalyst. Under simulated AM 1.5G irradiation, hydrogen is produced with photocurrent densities reaching 84 +/- 7 mu A.cm(-2), which is among the highest values reported so far for dye-sensitized photocathodes with surface-immobilized catalysts. Thanks to the unique combination of advanced spectroscopy and surface characterization techniques, the fast desorption of the dyad from the NiO electrode and the low yield of electron transfer to the catalyst, resulting in the Co demetallation from the diimine dioxime framework, were identified as the main barriers limiting the performances and the stability of the system. This work therefore paves the way for a more rational design of molecular photocathodes for solar fuel production and represents a further step toward the development of sustainable processes for the production of hydrogen from sunlight and water.

Mots clés: solar fuels; hydrogen; photoelectrochemistry; dye-sensitized; cobalt catalyst

Domaines: Matériaux; Catalyse

Emmanouil Giannoudis, Sébastian Bold, Caroline Müller, Alexander Schwab, Jakob Bruhnke, et al.. Hydrogen Production at a NiO Photocathode Based on a Ruthenium Dye-Cobalt Diimine Dioxime Catalyst Assembly: Insights from Advanced Spectroscopy and Post-operando Characterization. ACS Applied Materials & Interfaces, 2021, 13 (42), pp.49802-49815. ⟨10.1021/acsami.1c12138⟩. ⟨hal-03463903⟩