The effect of carbon support on rhenium-catalyzed glyceric acid deoxydehydration into biobased acrylic acid

The influence of carbon support structure on the dispersion, oxidation state, and catalytic activity of rhenium species was systematically investigated in the deoxydehydration (DODH) of bio-based glyceric acid towards acrylic acid. Rhenium based catalysts (targeting 5 wt% Re) were prepared by incipient wetness impregnation on activated carbons, carbon black, graphite, glassy carbon, and multiwalled carbon nanotubes. Comprehensive characterization by N 2 physisorption, scanning transmission electron microscopy, X-ray fluorescence, CO pulse adsorption, and X-ray photoelectron spectroscopy revealed that the support choice strongly affected rhenium particle size distribution, accessibility, and stabilization of oxidation states. Catalytic tests conducted at 150 °C under inert atmosphere in methanol solvent, identified activated carbon supports as the most effective, reaching combined selectivities up to 83 % toward DODH products (acrylic acid and methyl acrylate), comparable to those of the commercial Re/C catalyst. In contrast, the carbon black – supported catalyst exhibited very low activity toward DODH products, while the other carbon materials were practically inactive. The superior performance of activated carbon supports is due to the high surface area and mesoporous structure, which promotes better dispersion and accessibility of the active high valent Re species. These results highlight the decisive role of carbon support morphology and surface chemistry in governing the performance of rhenium catalysts, providing guidelines for the rational design of carbon-supported systems for biomass valorization.