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

Abstract

The water–gas shift reaction (WGSR) is a crucial industrial process for H₂ 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 Ni⁰ to Pt inhibited the formation of hydrogen carbonate intermediates for methanation. The methane by-product was eliminated by reducing the surface hydrogen concentration on Ni⁰. The accelerated H₂ desorption by HRS synergistically enhanced the intrinsic activity of Ni⁰ 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 Ni⁰ 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.