In this work, we have explored the feasibility of alveolar open-cell β-SiC foams as catalyst support for solar hydrogen production. For that purpose, Pt and Ru nanoparticles have been obtained, by means of photoassisted synthesis, on TiO2-coated foams and tested in gas-phase hydrogen production from water-ethanol mixtures in a tubular reactor coupled to a compound parabolic solar collector (CPC). Subnanometre-sized metal or metal/ oxide nanoparticles are obtained for Pt/TiO2/SiC and Ru/TiO2/SiC foams, respectively, where co-catalyst nanoparticles decorate the TiO2 coating which in turn is attached to the SiC foam through an amorphous SiO2 washcoat formed by SiC pre-calcination. In solar photocatalytic reactions, all of the assayed foam-supported photocatalysts are active for the production of hydrogen, with Pt/TiO2 ones being the most active and foam pore size exerting little influence on hydrogen outcome. In the best conditions, 14 % UV-to-hydrogen (equivalent to 0.49 % solar-to-hydrogen) conversion efficiency, with photonic efficiency higher than 30 %, is attained.

This work has received financial support from Spanish MCIN/AEI/ 10.13039/501100011033 and "ERDF A way of making Europe", through projects PID2020–118593RB-C22 and ENE2017-89170-R, from Comunidad de Madrid European Structural Funds through FotoArt-CM project (S2018/NMT-4367), and from the European Research Council (ERC) through the HyMAP.