Hydrogen reverse spillover eliminating methanation over efficient Pt-Ni catalysts for the water-gas shift reaction

The water-gas shift reaction (WGSR) is a crucial industrial process for H-2 production. Highly active Ni-based catalysts are possible substitutes for conventional Fe-Cr catalysts, but their industrial application is limited by the side-reaction of methanation. We report a Pt-Ni/NiPS catalyst using Ni phyllosilicate (PS) as the Ni catalyst donor and support for the WGSR. We discovered that hydrogen reverse spillover (HRS) from Ni-0 to Pt inhibited the formation of hydrogen carbonate intermediates for methanation. The methane by-product was eliminated by reducing the surface hydrogen concentration on Ni-0. The accelerated H-2 desorption by HRS synergistically enhanced the intrinsic activity of Ni-0 sites, with a 2-fold higher turnover frequency compared with that using Ni/NiPS. Hydrogen spillover from Pt to Ni during catalyst reduction promoted the reduction of Ni PS to generate more active Ni-0 sites on Pt-Ni/NiPS. Consequently, the apparent activity of Pt-Ni/NiPS was improved significantly. This catalyst also exhibited high stability in operation during the WGSR for 110 h.