Noble metal promoted Ni–Cu/La2O3–MgO catalyst for renewable and enhanced hydrogen production via steam reforming of bio-based n-butanol: effect of promotion with Pt, Ru and Pd on catalytic activity and selectivity

Abstract

Currently, production of high-purity hydrogen (H2) in a viable and sustainable manner is highly sought. H2 generation is possible by water splitting or biomass conversion as renewable resources. Bio-based n-butanol is a potential candidate for H2 production via catalytic steam reforming (SR) which is both of industrial and scientific significance. In the current work, a new catalyst is developed using La–Mg-based mixed metal oxide as support loaded with Ni–Cu as metals promoted by a suitable noble metal from Pt, Ru and Pd for steam reforming of n-butanol (SRB) in a fixed bed reactor. The effects of temperature, steam to carbon (S/C) ratio and gas hourly space velocity on hydrogen production from n-butanol were studied systematically. High n-butanol conversion (> 75%) and H2 yield (> 70%) were obtained. Particularly, the promotion with Pt resulted in the highest H2 concentration (> 90 mol%) with long-term stability of 25 h. The process optimization studies revealed that at T = 773 K, steam/carbon ratio (S/C) = 6 mol/mol and GHSV = 3120 h−1, maximum H2 concentration was obtained. The promotion with noble metals was further justified by the absence of coke formation and minimal metal sintering because noble metals help avert oxidation of Ni and Cu maintaining their active form. It was further bolstered through the cyclic stability studies which demonstrated that all catalysts remained stable for longer periods. A possible reaction mechanism on the synthesized catalysts is proposed in consonance with experimental data.