posted on 2021-05-25, 17:39authored byBing Ma, Matías Blanco, Laura Calvillo, Lingjing Chen, Gui Chen, Tai-Chu Lau, Goran Dražić, Julien Bonin, Marc Robert, Gaetano Granozzi
In
the quest for designing efficient and stable photocatalytic
materials for CO2 reduction, hybridizing a selective noble-metal-free
molecular catalyst and carbon-based light-absorbing materials has
recently emerged as a fruitful approach. In this work, we report about
Co quaterpyridine complexes covalently linked to graphene surfaces
functionalized by carboxylic acid groups. The nanostructured materials
were characterized by X-ray photoemission spectroscopy, X-ray absorption
spectroscopy, IR and Raman spectroscopies, high-resolution transmission
electron microscopy and proved to be highly active in the visible-light-driven
CO2 catalytic conversion in acetonitrile solutions. Exceptional
stabilities (over 200 h of irradiation) were obtained without compromising
the selective conversion of CO2 to products (>97%).
Most
importantly, complete selectivity control could be obtained upon adjusting
the experimental conditions: production of CO as the only product
was achieved when using a weak acid (phenol or trifluoroethanol) as
a co-substrate, while formate was exclusively obtained in solutions
of mixed acetonitrile and triethanolamine.