Alumina supported Cu nanoparticles derived from MOF crystallites for CO2 hydrogenation

Abstract

A carbon economy hinges on sustainable treatment and usage of greenhouse gases. Copper-based catalysts are an efficient way to make use of one of the most common greenhouse gases, carbon dioxide. In this work, a metal–organic framework decomposition method was used to synthesize a copper catalyst that was active and reproducible for methanol production via CO₂ hydrogenation. The properties of the as-prepared and decomposed MOF catalysts were analyzed using a wide range of characterization techniques (e.g. SEM, TEM, ICP-MS, XRD, N₂ adsorption, TGA, XPS, H₂-TPR) to rationalize the layer-by-layer synthetic approach to form the subsequent supported Cu nanoparticles. The catalytic performance of the MOF derived catalyst was compared to that of a sol-immobilization prepared Cu/Al₂O₃ catalyst in a fixed-bed continuous flow reactor for CO₂ hydrogenation. The MOF derived catalyst formed from ten iterative layers performed similarly to the sol-immobilization prepared catalyst but displayed increased methanol productivity at all reaction temperatures tested. This work indicates that synthesis of copper-based catalysts through MOF-templating is a viable method that would be impactful for future incorporation of secondary metals such as Zn, Ce, and/or Al that are typical additions for catalytic conversion of CO₂ to methanol.