Hydrogen assisted SO2 dissociation on the Pt-doped graphene quantum dot surface: a non-periodic DFT study

Behjatmanesh-Ardakani, Reza; Rzayev, Rovnag

doi:10.22034/crl.2024.489135.1476

Hydrogen assisted SO2 dissociation on the Pt-doped graphene quantum dot surface: a non-periodic DFT study

Document Type : Research Article

Authors

Reza Behjatmanesh-Ardakani ¹

Rovnag Rzayev ²

¹ Department of Chemical Engineering, Faculty of Engineering, Ardakan University

² Department of Engineering and Applied Sciences, Azerbaijan State University of Economics, UNEC, Azerbaijan

https://doi.org/10.22034/crl.2024.489135.1476

Abstract

In the previous study, it was shown that Pt-doped graphene quantum dot catalyst is a suitable catalyst for the adsorption and desorption of SO2, with a moderate adsorption energy of approximately -1 eV (the negative sign indicates that the adsorption is an exothermic process). However, the catalyst was not suitable for the dissociation of SO2 due to the high barrier energy (> 2 eV). In this paper, it is shown that the barrier energy for the dissociation of SO2 can be reduced with the co-adsorption of H2. Hydrogen gas requires only 0.27 eV of energy on the catalyst surface to be dissociated. With the co-adsorption of atomic hydrogen, the first step barrier energy of SO2 dissociation is reduced from +2.24 eV to +1.17 eV, and the second step barrier energy is reduced from +2.18 eV to +1.11 eV. The data show that all elementary steps are exothermic. The reaction energy of SO2 dissociation to SO + O is equal to -0.1 eV, while the reaction energy of SO dissociation to S + O is equal to -0.48 eV. The transition state structure for the first step is more similar to the reactants, while the structure of the transition state for the second step is exactly in the middle of the reaction path. Backward barrier energies for the two elementary steps are equal to +1.27 and +1.59 eV which are greater than the forward barrier energies.

Graphical Abstract