Core-shell bifunctional catalyst for steam methane reforming resistant to H2S: Activity and structure evolution

Abstract

Results of studies on the activity of the Ni-containing catalyst in the steam reforming of methane (SRM) process are presented. It is established that the catalyst shows high activity in SRM, stability to coke formation and resistance to H2S presence in the reaction gas mixture. The catalyst was prepared on the basis of mixed oxides separated from layered vermiculite. The structure and the phase composition of catalytically active components were investigated by XAFS, XRD, EDX, TEM and Moessbauer spectroscopy. It is found that the active components of catalyst are represented by clusters with core-shell configuration where FeNi alloy is a core (∼10 nm) surrounded by superparamagnetic γ-Fe2O3 shell (1–4 nm). These clusters are distributed in the mixed spinel Mg(Fe,Al)2O4 matrix. It is suggested that clusters of FeNi alloy are active in SRM while superparamagnetic γ-Fe2O3 particles are active in the oxidative decomposition of H2S.