Direct CO2 to methanol reduction on Zr6-MOF based composite catalysts: a critical review

The pressing problem of climate change on account of anthropogenic greenhouse-gas emissions underlines the necessity for carbon capture and utilisation technologies. Several heterogeneous catalyst systems allowing the conversion of waste CO2 into desirable products, such as methanol, have emerged as promising and potentially viable solutions to this perennial problem. In particular, composite catalysts based on hexanuclear zirconium metal–organic framework matrices have shown much promise in the direct conversion of CO2 into value-added and useful products. Herein, we critically review the literature in this area and relate differences in composition, defect chemistry, and structural characteristics, their reaction conditions with their performance and stability in the thermocatalytic hydrogenation of CO2 to methanol, on the basis of both experimental and theoretical studies. We also highlight the obstacles in directly comparing the performance of these systems for CO2 hydrogenation and suggest potential solutions and opportunities for further advancement.