# New theoretical insights into doping-induced enhancement of ORR activity in molybdenum disulfide: d–p hybridization or the Jahn–Teller effect?

## TL;DR

This paper explains how doping molybdenum disulfide can improve its ability to catalyze oxygen reduction reactions through two distinct electronic mechanisms.

## Contribution

The paper identifies two new theoretical mechanisms—d–p hybridization and the Jahn–Teller effect—for enhancing MoS2 electrocatalytic activity.

## Key findings

- Doping with d1–d3 metals enhances ORR activity by elevating the sulfur p-band center and reducing overpotential to 0.87 V.
- Doping with d7–d9 metals activates the Jahn–Teller effect, inducing lattice distortion and lowering ORR overpotential to 0.53 V.
- The study provides guiding principles for designing efficient MoS2-based electrocatalysts through substitutional doping.

## Abstract

Molybdenum disulfide (MoS2) has emerged as a promising electrocatalyst, garnering considerable attention in recent years. However, the extensive basal-plane sites remain intrinsically inert, thereby limiting the overall catalytic efficiency. Heteroatom doping has been demonstrated as an effective strategy for activating these otherwise inert sites; nevertheless, theoretical investigations remain relatively limited, and the broad diversity of dopants has led to conflicting interpretations of the underlying mechanisms. To elucidate the role of dopants in activating these sites, a total of 64 MoS2-based electrocatalysts incorporating 3d, 4d, and 5d transition metals, along with selected nonmetals, have been systematically investigated. The results reveal two distinct enhancement pathways: (i) d–p hybridization (d1–d3 dopants), which elevates the sulfur p-band center and reduces the oxygen reduction reaction (ORR) overpotential to 0.87 V; and (ii) the Jahn–Teller effect (d7–d9 dopants), which lifts the orbital degeneracy between dxz/dyz and dx2−y2/dxy, thereby inducing lattice distortion. The electron rearrangement at the metal center reduces charge transfer, thereby lowering the electron occupancy of the sulfur atom, upshifting its p-band center, and enhancing ORR performance by decreasing the overpotential to 0.53 V. In summary, these findings provide new theoretical insights into substitutional doping and establish guiding principles for the rational design of efficient MoS2-based ORR electrocatalysts.

Systematic screening reveals two mechanisms, d−p hybridization and Jahn−Teller distortion, that modulate the electronic structure of MoS2, enabling substantial ORR overpotential reduction and offering design principles for efficient catalysts.