Study of the Rate-Determining Step of Rh Catalyzed CO2 Reduction: Insight on the Hydrogen Assisted Molecular Dissociation

In the context of climate change mitigation, CO2 methanation is an important option for the production of synthetic carbon-neutral fuels and for atmospheric CO2 recycling. While being highly exothermic, this reaction is kinetically unfavorable, requiring a catalyst to be efficiently activated. Recently Rh nanoparticles gained attention as effective photocatalyst, but the rate-determining step of this reaction on Rh surface has not been characterized yet. In this work, Density Functional Theory and Nudged Elastic Band calculations were performed to study the Rh-catalyzed rate-determining step of the CO2 methanation, which concerns the hydrogen assisted cleavage of the CO* molecule and subsequent formation of CH* and O* (* marks adsorbed species), passing through the CHO* key intermediate. The configurations of the various adsorbates on the Rh (100) surface were investigated and the reaction mechanism was studied exploiting different exchange-correlation functionals (PBE, RPBE) and the PBE+U technique. The methanation rate-determining step consists of two subprocesses which subsequently generate and dissociate the CHO* species. The energetics and the dynamics of such processes are extensively studied and described. Interestingly, PBE and PBE+U calculated activation barriers are in good agreement with the available experimental data, while RPBE largely overestimate the CHO* dissociation barrier.

Feasibility analysis of a CO2 recycling plant for the decarbonization of formate and dihydroxyacetone production

Renewable-driven CO2 recycling plants (CO2RPs) to produce chemicals have a certain role to play in the decarbonization of the economy. In recent years, significant progress has been found for the...

Kinetics of CO2 Reduction Reaction in Aprotic Li-CO2 Batteries: A Model Study

The aprotic Li-CO2 battery represents a promising technology that can potentially achieve energy conversion and storage and CO2 recycling simultaneously. However, current Li-CO2 batteries suffer from the sluggish kinetics of...