Identification of the Nearby Hydroxyls’ Role in Promoting HCHO Oxidation over a Pt Catalyst

Abstract

Insight into the relationship between catalytic trends and physicochemical properties of composite nanoparticles is essential for their rational design. Herein, a series of 3d-M (M = Mn, Fe, Co, Ni) metal hydroxide-promoted PtM(OH)x/Al2O3 catalysts are developed and well characterized for establishing the catalytic HCHO oxidation reactivity trend as a function of more fundamental properties, such as hydroxyl concentration and adsorption strength. The reactivity of PtM(OH)x/Al2O3 exhibits an increasing trend of Mn < Fe < Co < Ni, which is governed by their OH–M2+δ bond strength (Ni < Co < Fe < Mn) and surface hydroxyl concentration (Mn < Fe < Co < Ni). Both PtCo(OH)x/Al2O3 and PtNi(OH)x/Al2O3 exhibit a (>)95% HCHO conversion and (>)100 h performance stability at 30 °C with a low 0.2 wt % Pt loading amount. The identification of these catalytic trends provides foundations for composite active sites design for HCHO oxidation and other hydroxyl-involved reactions.