Single-Atom Pt Anchored on Oxygen Vacancy of Monolayer Ti3C2Tx for Superior Hydrogen Evolution

Two-dimensional (2D) MXene-loaded single-atom (SA) catalysts have drawn increasing attention. SAs immobilized on oxygen vacancies (O_V) of MXene are predicted to have excellent catalytic performance; however, they have not yet been realized experimentally. Here Pt SAs immobilized on the O_V of monolayer Ti₃C₂T_x flakes are constructed by a rapid thermal shock technique under a H₂ atmosphere. The resultant Ti₃C₂T_x-Pt_SA catalyst exhibits excellent hydrogen evolution reaction (HER) performance, including a small overpotential of 38 mV at 10 mA cm^–2, a high mass activity of 23.21 A mg_Pt^–1, and a large turnover frequency of 23.45 s^–1 at an overpotential of 100 mV. Furthermore, density functional theory calculations demonstrate that anchoring the Pt SA on the O_V of Ti₃C₂T_x helps to decrease the binding energy and the hybridization strength between H atoms and the supports, contributing to rapid hydrogen adsorption–desorption kinetics and high activity for the HER.