TiO 2 -mediated visible-light-driven hydrogen evolution by ligand-capped Ru nanoparticles

Nuria Romero (1) , Renan Barrach Guerra (2) , Laia Gil (1) , Samuel Drouet (3) , Ivan Salmeron-Sànchez (1) , Ona Illa (1) , Karine Philippot (3) , Mirco Natali (4) , Jordi García-Antón (1) , Xavier Sala (1)

1 UAB - Departament de Química [Barcelona]
2 UNICAMP - Universidade Estadual de Campinas = University of Campinas
3 LCC - Laboratoire de chimie de coordination
4 UniFE - Università degli Studi di Ferrara = University of Ferrara

Ru nanomaterials have recently emerged as potential substitutes for classical Pt-based cathodes for the hydrogen evolution reaction (HER). In this regard, nanoparticle surface-functionalization through the so-called organometallic approach is a promising strategy towards synthesizing tailored highly active and durable HER (photo)electrocatalysts with limitless tunability. Herein, efficient (turnover numbers over 480 molH2 molRu−1 and a turnover frequency of 21.5 molH2 h−1 molRu−1; apparent quantum yield of 1.3%) and durable (>100 h) visible-light-driven hydrogen evolution has been achieved at neutral pH with a ternary hybrid nanomaterial combining 4-phenylpyridine-capped Ru nanoparticles (RuPP), TiO2 nanocrystals and [Ru(bpy)2(4,4′-(PO3H2)2(bpy))]Cl2 (RuP) using triethanolamine (TEOA) as a sacrificial electron-donor. Photophysical analysis by means of transient absorption spectroscopy has been performed in order to shed light on the kinetics of the electron transfer events and to identify the rate-determining step of the overall photocatalytic process. TiO2 is shown to have a key role as (1) the support aiding the dispersion of the photocatalyst and limiting its agglomeration under turnover conditions and (2) the electron-transfer mediator enabling efficient electron communication between the catalyst and the anchored molecular photoabsorber. Finally, the evolution and fate of the photocatalyst in long-term HER photocatalysis are thoroughly analyzed.

Domaines: Chimie de coordination

Nuria Romero, Renan Barrach Guerra, Laia Gil, Samuel Drouet, Ivan Salmeron-Sànchez, et al.. TiO 2 -mediated visible-light-driven hydrogen evolution by ligand-capped Ru nanoparticles. Sustainable Energy & Fuels, 2020, 4 (8), pp.4170-4178. ⟨10.1039/D0SE00446D⟩. ⟨hal-03044103⟩