Hydrogenation of sodium hydrogen carbonate in aqueous phase using metal/activated carbon catalysts

The catalytic hydrogenation of sodium hydrogen carbonate in aqueous phase (NaHCO3) to produce sodium formate (or formic acid) on activated carbon-supported metal (Pd, Ru, Ni, Co and Re) species at 25 degrees C and 1 bar of hydrogen was studied. The reaction was performed in a semi-continuous flow reactor, and the formate (or formic acid) production was quantified by HPLC, while the gas feed and possible products were quantified by gas chromatography. The catalysts were characterized by N-2 adsorption, Temperature-Programmed Reduction (TPR), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and carbon monoxide chemisorption. All the catalysts displayed activity in the hydrogenation of sodium hydrogen carbonate and the selectivity to sodium formate was 100%. The Pd/C catalyst presented the highest activity, attributed to stabilized adsorption of reactant which favors the hydrogenation process. The highest intrinsic hydrogenation performance of this metal is related to stability of reduced phases of Pd species observed by XPS and TPR results, favoring the formation of formic acid.