Revealing the elementary processes controlling the conversion of small and abundant molecules to added-value chemicals and materials

The transformations of the abundant small molecules such as carbon dioxide (CO₂) and methane (CH₄) has the potential to contribute toward establishing an environmentally sensible circulation of energy and materials. In this talk, I will discuss recent results conducted in my group at Queen Mary University on the use of computational chemistry as a tool to reveal the early stages of these conversion processes and to support the design of catalysts and operation conditions promoting this conversion. The talk will give an overview of the following research topics:

• Solution composition conditions promote the low-temperature CO₂ conversion into magnesite (MgCO₃). Magnesite can be formed via aqueous carbonation of Mg²⁺ ions and represents a promising route to carbon capture and reuse, albeit limited by the slow precipitation of MgCO₃. The principal difficulty arises from the very strong Mg²⁺···H2O interaction, raising barriers to Mg-dehydration. We have used atomistic simulations, complemented by spectroscopic experiments, to investigate the influence of solution additives on the various stages of aqueous MgCO₃ formation: Mg²⁺ dehydration; pre-nucleation Mg²⁺∙∙∙CO₃^2– pairing; surface growth. Results show which solution conditions lower the barrier to Mg²⁺ dehydration and subsequent incorporation into the lattice of Mg-carbonates. I will report the design of a carbonation rig to perform real-time, in-situ neutron measurements of CO₂ mineralization at the Rutherford Appleton Laboratory.
• The CH₄ conversion to porous nanographene on transition-metal-free catalysts. Graphene mesosponge (GMS) is a new class of high-performing materials consisting of single-layer graphene walls. I will report an investigation of the early-stage CH₄ activation toward GMS on γ-Al₂O₃, MgO and CaO nanoparticles via reaction kinetics and surface analysis. The results show the role of defects in accelerating CH₄ carbon vapour deposition.
• Ab initio random structure searching of Cu-based nanocluster for the electrocatalytic conversion of CO₂. Finally, we will present the development of a computational approach based on density functional and random structure searching to investigate the structures of mono- and bi-bimetallic nanoclusters and the CO₂ activation. We will show the most stable and active catalysts are amorphous copper clusters. I will report a detailed characterisation of CO₂ activation on these nanoclusters and the reaction pathways of the CO₂-to-CO conversion and the competitive hydrogen evolution reaction. The results could predict the optimal copper and copper-metallic nanocatalysts.

Biography

Devis Di Tommaso was born and raised in Italy. He studied Chemistry at University of Trieste. Here, he also carried out his doctoral studies in the Theoretical Chemistry group headed by Professor Piero Decleva with a thesis on the work on the application and development of density functional theory methods for the study of molecular photoionization processes.

In 2006, Devis conducted postdoctoral research at the Royal Institution of Great Britain in the group of Professor Richard Catlow, focusing on theoretical catalysis. As part of a Marie-Curie research and training network, in 2007 he moved to University College London in the group of Professor Nora de Leeuw to work on computer simulation of nucleation and growth of metal carbonates from solution. In January 2012 he was awarded a Royal Society Industry Fellowship with AstraZeneca.

Devis joined the School of Biological and Chemical Sciences at Queen Mary in September 2013. He was promoted to Senior Lecturer (Associate Professor) in 2020. 

Devis’ research interest includes theoretical catalysis, CO₂ conversion, aqueous thermodynamic modelling. He currently leads an EU-funded consortium, FUNMIN, to accelerate the process of CO₂ mineralization from solution.