Tri-reforming of methane for syngas production using Ni catalysts: Current status and future outlook

Tri-reforming of methane (TRM) emerged as an attractive approach for syngas production that combines the methane steam reforming (SMR), dry reforming (DRM) and partial oxidation (POX) reactions in a single process. The key merits of the TRM process are the ability to use flue gas directly in the process feedstock, the great flexibility to control the H2/CO ratio for downstream processes, and the relatively lower energy demand and carbon footprint. Considerable progress was achieved over the past decade in catalyst development, process modeling and optimization for syngas production using the TRM process. In this work a critical review of the literature pertaining to Ni-based catalyst development, TRM reaction kinetics, process development, and eco-nomics is presented. The use of Ni-based catalysts has received significant attention in recent years; hence this work aims to provide a summary and a critical analysis of the advancement achieved in the design of Ni-based catalysts. Developing active Ni-based catalysts with enhanced resistance to coke formation for the TRM process is anticipated to pave the way for further commercialization ventures. Ni catalysts supported on a wide range of support materials such as Al2O3, CeO2, ZrO2, TiO2, MgO and their mixed oxides are the most widely used cat-alysts for TRM processes. This review provides a critical analysis of the different attempts made to tune the catalyst properties such as the use of different supports, promotors, and synthesis protocols. Catalyst properties such as Ni dispersion, basicity, Ni particle size, thermal stability is evaluated for various catalytic systems to develop structure-property relationship in TRM processes. Moreover, studies on TRM reaction kinetics, process modeling, and economics are also reviewed. Future outlook in catalysts and process development is also pre-sented in this review to shed lights on the potential pathways to develop TRM processes in an environmentally friendly, and cost-effective manner.