Ni-Silica-based Catalysts for CH4 Reforming by CO2 with Enhanced Stability: Recent Designs and the Impacts of Ni Confinement, Promoters, and Core-Shell Structures

Abstract

CO2 reforming of CH4, also referred to as the Dry Reforming of Methane (DRM), is considered an excellent method to produce H2 and CO (syngas), which are known to be used for the production of higher alkanes and oxygenates. Despite nickel’s moderate toxicity, Ni-based heterogeneous catalysts are considered excellent candidates for use in DRM due to their reasonable performances and economic advantages. However, these materials also present severe drawbacks, such as sintering of the active phase and coke (carbon) deposition, which may, in certain cases, lead to severe catalyst deactivation. Several synthesis strategies, mostly based on the stabilization of nickel through oxide support, have been developed to overcome these issues. Silica-based materials are investigated widely due to their availability, high surface area, and the confinement capacity conferred by their controlled porosity. The present review summarizes the progress in the design of Ni/silica-based catalysts for the dry reforming of methane between the years 2015 and 2018. The different strategies implemented are discussed to assist future research works in designing the anti-coking and anti-sintering nickel-silica-based catalysts.

Catalytic Upgrading of Clean Biogas to Synthesis Gas

“…Although using silica as a support facilitates the reduction in Ni species, weak interaction between active phase and support causes rapid deactivation (from 90% to 80% for both CH 4 and CO 2 after 100 h of reaction at 750 • C) [89]. High surface area values and the possibility to obtain support with a specific lattice structure have been claimed as the responsible for the performances of Ni/SBA-15, Ni/MCM41 or other amorphous silica supports [60,88,[90][91][92][93][94]. Good results in dry, combined and tri-reforming of methane have also been obtained with Ni/ZrO 2 catalysts well-known to be stable at high temperatures [88,[95][96][97][98].…”

Effect of Impregnation with Ammonia vs Silica Support Textural Properties on Ni Nanoparticle Catalysts for Dry Reforming of Methane

“…Regarding siliceous supports, many strategies have been used to improve the dispersion of nickel nanoparticles, which is quite challenging for silica compared to alumina. − Everything that favors the silica/nickel interaction before reduction should be beneficial. Furthermore, the use of a mesoporous support, which is supposed to provide an effective physical protection of all Ni atoms against migration and aggregate formation taking place during the drying and activation steps of DRM, , seems to be a suitable option (Table S1).…”