Catalisador de níquel suportado em óxido de grafeno termicamente reduzido para produção de hidrogênio por reforma a seco do metano

Abstract

In recent decades, the significant increase in energy consumption, driven by population growth and intensified industrial activity, has greatly expanded the demand for fossil fuels, contributing to the rise in greenhouse gas (GHG) emissions. Among the main contributors to this climate crisis are methane and carbon dioxide, with natural gas combustion being a relevant source of these emissions. In this context, strategies such as carbon capture and storage (CCS) and the transition to renewable energy sources have become essential. Dry reforming of methane (DRM) has gained growing interest for combining the mitigation of two GHGs with the production of strategic industrial feedstocks. The success of DRM depends heavily on the choice and performance of the catalyst. Nickel has emerged as a cost-effective alternative to noble metals, due to its lower cost and good catalytic activity. However, its susceptibility to sintering and carbon deposition limits its operational stability, requiring the development of supports that promote metal dispersion and provide greater thermal and structural resistance. In this scenario, graphene oxide (GO) and its thermally reduced form (TrGO) emerge as promising supports, due to their high specific surface area, excellent thermal and electrical conductivity, and ability to form strong interactions with metal particles. This study aims to investigate the performance of nickel catalysts supported on reduced GO (Ni-TrGO), assessing how crystal structure, surface morphology, metal dispersion, and nickel content influence catalytic activity during DRM. For this purpose, two distinct formulations (5% and 20% wt Ni) were synthesized and characterized using various analytical techniques, aiming to correlate physicochemical properties with CH₄ and CO₂ conversion parameters, H₂ and CO yield, and post-reaction thermal stability. The results demonstrate that metal–support interactions improve catalytic performance as nickel content increases, aiding in the identification of more effective catalyst formulations for applications in energy valorization processes with lower environmental impact.