Exsolution of Re-alloy catalysts with enhanced stability for methane dry reforming

Abstract

The valorization of natural gas is a highly important process which could enable the production of hydrogen or clean synthetic fuels. Methane reforming with carbon dioxide provides an environmentally friendly route for methane conversion to synthesis gas while consuming two greenhouse gasses. Large-scale implementation of this process has been stalled by the lack of stable catalysts owing to variety of deactivation mechanisms such as carbon accumulation (coking) and sintering. We created doped perovskite precursors based on lanthanum ferrite (LaFeO 3) and subsequently doped them with Ni and Re phases. Under reducing conditions, these composite precursors exsolved Re-alloy nanoparticles which were found to be active and stable under dry reforming conditions. The solid-phase crystallization process was studied by in-situ synchrotron XRD, and compared to the temperature programmed reduction of each precursor. No carbon accumulation or nanoparticle sintering was observed after 70 hours of operation. Furthermore, the evaporation of catalytic Re phases, a major problem under reforming conditions, was shown to be completely blocked due to strong catalyst-support interactions imbued by this synthesis technique.

High‐Performance Bimetallic Catalysts for Low‐Temperature Carbon Dioxide Reforming of Methane

“…Zubenko et al examined Ni and Re loaded on a LaFeO 3 perovskite precursor via solid‐phase crystallization for CO 2 reforming of CH 4 . The excellent activity and stability was attributed to the presence of Re‐alloy nanoparticles (Ni‐Fe, Re‐Fe, and Re‐Ni‐Fe) as consequences from the exsolution process of the perocskite precursor.…”

“…Wysocka et al [15] [16]. The excellent activity and stability was attributed to the presence of Re-alloy nanoparticles (Ni-Fe, Re-Fe, and Re-Ni-Fe) as consequences from the exsolution process of the perocskite precursor.…”

Effect of Fe and Mn Substitution in LaNiO3 on Exsolution, Activity, and Stability for Methane Dry Reforming

“…The DRM has been previously investigated on many catalysts based on noble and transition metal elements. Although noble-metal catalysts are active and less sensitive to carbon accumulation, Ni-based catalysts are preferred due to their ability to activate the C-H bond, relatively low cost, and availability [6][7][8][9]. It is well known though that Ni-based catalysts suffer from deactivation during DRM largely owing to coking and sintering [10,11].…”

Recent Scientific Progress on Developing Supported Ni Catalysts for Dry (CO2) Reforming of Methane

“…Recently, mesoporous silica and alumina has been received much attention as supports of Ni nanoparticles since Ni nanoparticles that are embedded in pores of those supports can exhibit good sintering resistance at high temperature [74][75][76][77][78][79]. Zhang et al demonstrated that mesoporous structure of SBA-15 can prevent sintering of monometallic Ni particles by confining their size inside the pores [74].…”

“…Zhang et al demonstrated that mesoporous structure of SBA-15 can prevent sintering of monometallic Ni particles by confining their size inside the pores [74].…”