Enhanced steam and sulfur resistance of Ni-based catalysts in LPG steam reforming via trace pt-induced hydrogen spillover

This study focuses on a Pt-promoted Ni/NiAl (Ni/NiO-Al 2 O 3 ) catalyst for butane steam reforming, designed to overcome hydrothermal oxidation and sulfur poisoning in Ni-based systems. A series of Ni/Al (Ni/Al 2 O 3 ) and Ni/NiO-Al 2 O 3 catalysts, with and without Pt modification, were synthesized and systematically evaluated under severe reforming conditions. Compared with conventional Ni/Al, Ni/NiAl exhibited stronger metal-support interaction through NiAl 2 O 4 formation but suffered rapid deactivation in steam-rich and sulfur-containing atmospheres. Incorporating 0.5 wt% Pt markedly improved stability, maintaining high activity and hydrogen selectivity during both steam and H 2 S exposure. Characterization by XRD, TEM, H 2 -TPR, and XPS revealed that Pt induces a synergistic protection mechanism, in which hydrogen spillover dynamically regenerates oxidized Ni species and weakens Ni S interactions. This effect reduces sulfur coverage on active Ni sites, preserving highly dispersed metallic Ni 0 . Time-resolved outlet gas analysis further indicated that sulfur preferentially deactivates reforming sites, followed by progressive inhibition of the water-gas shift reaction via a COS-mediated pathway. The catalyst demonstrated excellent stability under 5 ppm H 2 S at 850 °C, confirming the dual protective role of Pt against oxidation and sulfur poisoning. These findings provide mechanistic insights and design principles for robust, regenerable Ni-based catalysts tailored for distributed hydrogen production from LPG.