Theme 2 aims to use the photo-generated hydrogen (from Theme 3) as a proton source for the catalytic reduction of carbon dioxide. It is well known that CO2 conversion is possible with the use of precious metal catalysts. However, in order to meet the strict goals of the life cycle analysis it is important to develop more affordably catalysts that are efficient enough to enable the integrated low carbon production of chemicals to compete with more traditional synthesis routes. Fortuitously, recent work with transition metal carbides has indicated that these materials may have Platinum-like properties that can afford them the ability for converting CO2 to various industrially useful products. These extremely durable material are also very stably at the heats and pressures associated with potential industrial applications and therefore will be the main focus of this research theme.
Density functional theory will be used to screen a large number of potential carbides for both their physical / electronic properties as well as for their potential catalytic activity. The adsorption of hydrogen and carbon dioxide will be simulated computationally in order to predict the potential catalytic activity of each material. Whereby, the characterisation of minima and transition state structures will allow us to obtain activation barrier for each step in CO2 conversion by molecular hydrogen. Additionally, the adsorption of other compounds present in flue gas will also be considered to obtain a holistic model of the potential functionality of each material.
Detailed studies of the potential energy surfaces of each carbide will enable our group to focus on good candidates for further experimental characterisation. To this end, microkinetic models will be applied to extrapolate the reaction conditions from our theoretical data. Thereafter, our collaborators from Queens University Belfast will undertake experimental validation of our theoretical findings.