Predicting the Effect of Dopants on CO₂ Adsorption in Transition Metal Carbides: Case Study on TiC (001)

Abstract

Previous work has shown that doping the TiC(001) surface with early transition metals significantly affects CO 2 adsorption and activation which opens a possible way to control this interesting chemistry. In this work we explore other possibilities which include non-transition metals elements (Mg, Ca, Sr, Al, Ga, In, Si, Sn) as well as late transition metals (Pd, Pt, Rh, Ir) and lanthanides (La, Ce) often used in catalysis. Using periodic slab models with large supercells and state-of-the-art density functional theory (DFT) based calculations, we show that, in all the studied cases, CO 2 appears as bent and, hence, activated. However, the effect is especially pronounced for dopants with large ionic crystal radii. These can increase desorption temperature by up to 230K, almost twice the value predicted when early transition metals are used as dopants. However, a detailed analysis of the results shows that the main effect does not come from electronic structure perturbations but from the distortion that the dopant generates into the surface atomic structure. A simple descriptor is proposed that would allow predicting the effect of the dopant on the CO 2 adsorption energy in transition metal carbide surfaces without requiring DFT calculations. File list (2) download file view on ChemRxiv CO2-doped-TMCs-final.pdf (2.71 MiB) download file view on ChemRxiv CO2-doped-TMCs-SI.pdf (10.28 MiB)

First-principles study on the effects of N and Al doping on the mechanical properties and electronic structures of TiC

“…Titanium carbide, a typical transition metal carbide, has been applied in cutting tools, 1 hard coatings, 2,3 grain inhibitors 4 as well as a catalyst [5][6][7] for years. It is not only due to its desirable physical properties such as high hardness, high melting points, low density and corrosion resistance but also the chemical stability and low thermal expansion coefficient draw huge attention in manufacturing industries.…”

Transition Metal Carbides (TMCs) Catalysts for Gas Phase CO2 Upgrading Reactions: A Comprehensive Overview

“…This finding provides a useful descriptor that allows one to predict the effect on the adsorption energy of other dopants without needing to carry out any DFT calculation. Hopefully further experimental works can be triggered in this field [89].…”

Atomistic and electronic structure of metal clusters supported on transition metal carbides: implications for catalysis

“…For a discussion on how the cluster size can affect these properties, the reader is referred to the work by Lozano-Reis et al 18 Moreover, it is worth pointing out that another interesting approach to tune the catalytic activity of TMCs is by transition metal doping. Interestingly, López et al 45,46 used DFT calculations to show that doping TiC(001) with other elements can modify its interaction with CO 2 . However, there are no experimental studies on these systems yet, and the number of elements that can be used as dopants is limited.…”