Unraveling the Electrocatalytic Activity of Platinum Doped Zirconium Disulfide toward the Oxygen Reduction Reaction
Ashok Singh, Srimanta Pakhira
Abstract
The O2 reduction reaction (ORR) is one of the important reactions and the heart of renewable energy technology, ranging from fuel cells to metal-air batteries, and it is a large and challenging task to build a cost-effective and efficient cathodic material for the electrocatalytic ORR. We computationally designed Pt-doped 2D monolayer zirconium disulfide (i.e., Pt-ZrS2) transition metal dichalcogenides (TMDs) and studied the electronic and structural properties by employing the hybrid periodic Density Functional Theory (DFT-D) method with van der Waals dispersion corrections. The electronic properties calculations suggest the semiconducting character of Pt-ZrS2 with the electronic band gap of 1.95 eV which is an essential aspect in studying the ORR mechanism. The basal plane of 2D Pt-ZrS2 shows exceptional electrocatalytic activities toward the ORR with a high four-electron (4e–) reduction reaction pathway selectivity. Here, the detailed ORR pathway with the mechanism was envisaged on the surfaces of 2D monolayer Pt-ZrS2 TMD by employing the same DFT-D method. Both the dissociative (O2* → 2O*) and associative (O2* → O_OH*) ORR mechanisms have been investigated, and it was found that only the dissociative reaction path is favorable. The adsorption energy has been calculated in each intermediate state during the ORR which guides us to predict the potential of Pt-ZrS2 as an effective electrocatalyst for the ORR. This study reveals that substituting a Zr atom in the 2 × 2 supercell of the monolayer ZrS2 with a Pt atom activates the inert basal planes, advancing to its superior electrochemical reactivity for boosting the molecular O2 and successive ORR steps. Therefore, Pt-ZrS2 can be used to design 2D cathode material for fuel cell contents.