Single-Atom Pt Anchored on Oxygen Vacancy of Monolayer Ti 3 C 2 T x 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 Ti 3 C 2 T x flakes are constructed by a rapid thermal shock technique under a H 2 atmosphere. The resultant Ti 3 C 2 T 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 Ti 3 C 2 T 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.