Performance of catalysts with Nb₂O₅ for hydrogen production from ethanol steam reforming

Abstract

Cu/Nb₂O₅ and Cu/Nb₂O₅/Al₂O₃ were studied as catalysts in ethanol steam-reforming for hydrogen production. They were prepared through impregnation, with different copper and Nb₂O₅ concentrations. Cu/ZnO/Al₂O₃ (G66), a commercial catalyst for methanol reforming was used for comparison. Temperature-programmed reduction data showed incomplete reduction of the copper, resulting in two reduction peaks, in opposition to CuO bulk, whose reduction occurred in one step (only one peak), it evidences a copper modification through Nb₂O₅. Results of diffuse reflectance spectra also evidenced the interaction. The catalytic tests showed that the niobium oxide dispersion on alumina improved the catalyst action; the ternary catalysts are the ones that show higher hydrogen production. They also produce ethyl ether as side product. The binary catalysts don't present parallel reaction, probably because when Cu/Nb₂O₅ is dispersed on alumina there is another type of catalytic site production, which produces ethyl ether.