Titanium-doped MoS₂ monolayer as highly efficient catalyst for hydrogen evolution reaction

Abstract

The effects of Ti dopants on the catalytic activities of the hydrogen evolution reaction (HER) in monolayer MoS2 basal plane were investigated using density functional theory. Our study shows that Ti dopants that substituted Mo atoms in MoS2 have small formation energy, and the complex dopant structures involving multiple Ti sites are energetically more stable than the isolated ones. Doping Ti atoms greatly improves the catalytic performances of MoS2 with a near-ideal hydrogen-adsorption Gibbs free energy. Projected density of states analysis revealed that the mechanism for the improvement of catalytic activity is due to formation of the density of states near the Fermi energy level upon increasing dopant concentrations. It can be expected from the current results that excellent catalytic performance can be obtained by atomic composition modifications, such as Ti doping in the HER reaction.

Facilitating the Hydrogen Evolution Reaction on Basal-Plane S Sites on MoS2@Ni3S2 by Dual Ti and N Plasma Treatment

“…Among various doping strategies, ,− plasma-assisted techniques are widely recognized owing to their advantages of uniform doping, scalable processing, high efficiency, and compatibility with advanced microelectronic fabrication. − Our previous studies have systematically investigated the doping effect on the atomic structure and the improved catalytic activity of doped MoS 2 grown at Ni 3 S 2 nanorods on nickel foam (MSNF) via plasma techniques, including Ag, Ti, Cr, C, and N . In particular, Ti-doped MSNF is feasible to prepare owing to the low formation energy . Despite the excellent HER activity of individual-doped MSNFs (Tafel slope: 41.7 mV dec –1 ), the catalytic mechanism of doped MoS 2 in alkaline water electrocatalysis is still not well understood.…”

“…36−38 Our previous studies have systematically investigated the doping effect on the atomic structure and the improved catalytic activity of doped MoS 2 grown at Ni 3 S 2 nanorods on nickel foam (MSNF) via plasma techniques, including Ag, Ti, Cr, C, and N. 39 In particular, Ti-doped MSNF is feasible to prepare owing to the low formation energy. 40 Despite the excellent HER activity of individual-doped MSNFs (Tafel slope: 41.7 mV dec −1 ), the catalytic mechanism of doped MoS 2 in alkaline water electrocatalysis is still not well understood. Especially, the dissociation of water molecules is one of the most important steps impacting the alkaline HER activity.…”