Carbon Dioxide Activation and Hydrogenation into Value-Added C1 Chemicals over Metal Hydride Catalysts

The utilisation of fossil fuels has resulted in the continuous increase in anthropogenic carbon dioxide (CO2) emissions and has led to significant environmental impacts. To this end, the catalytic hydrogenation of captured CO2 into value-added C1 chemicals has attracted great attention. In this case, significant research efforts have been directed towards the development of heterogeneous catalysts. Owing to the unique properties and functionalities of hydridic hydrogen (H−), metal hydrides have shown great promise in hydrogen-involved catalytic processes. This is attributed to their enhanced hydrogen (H2) absorption-desorption reversibility and newly developed active sites. Nevertheless, their application in the activation and hydrogenation of CO2 has been overlooked. In this review paper, we provide an overview of recent advances in catalytic CO2 hydrogenation using metal hydride-based materials. Firstly, the reaction mechanisms of CO2 hydrogenation toward different C1 products (CO, CH4, CH3OH and HCOOH) are introduced to better understand their application trend. Thereafter, we highlight the challenges of developing robust hydride catalysts with different components and structures that enable tuning of their catalytic activity and selectivity. A brief introduction of the CO2 hydrogenation over typical homogeneous metal hydrides complexes is also presented. Lastly, conclusion, future outlook and perspectives are discussed.