Atomic-level precision engineering: Single-atom catalysts with controlled loading density for efficient hydrogen evolution reaction.

Varying the ratio of MoS 2 on MoS 2 /rGO, and thus controlling the density of Pt SA oriented to grow on MoS 2 , a unique single atom catalyst with a 2D/2D structure was constructed, realising precise atomic control and efficient hydrogen evolution reaction under the acidic condition. [Display omitted] • A simple hydrothermal method was used to construct the 2D carrier, and the loading density of single-atom platinum (Pt SA) was precisely controlled by a directional growth strategy. • Pt SA -MoS 2 /rGO with optimised geometrical and electronic structures exhibits an ultra-low overpotential (η 10 = 11 mV) and long-term stability in acid condition for hydrogen evolution reaction (HER). • DFT shows that the increased loading density of Pt SA on the MoS 2 surface promotes the reduction of ΔG H* , which is the driving force for the kinetic process of electrocatalytic HER. An important but challenging task in single-atom catalysis is synthesizing a catalyst with controllable single-atom loading densities and no metal agglomeration. Here, we construct MoS 2 /rGO supports by a simple hydrothermal method and precisely control single-atom platinum (Pt SA) loading density by its targeted growth on MoS 2 for electrocatalysis. Using the optimized geometric and electronic structure, Pt SA -MoS 2 /rGO exhibits an ultra-low overpotential of 11 mV at − 10 mA cm−2 in 0.5 M H 2 SO 4 for electrocatalytic hydrogen evolution reaction (HER). First-principles calculations reveal that enhanced density of Pt SA on the MoS 2 surface favors the reduction of Gibbs free energy of hydrogen adsorption, facilitating the kinetic process of electrocatalytic HER. This work provides a new engineering route to fabricating a series of performance-tunable single-atom catalysts with controllable locations and loading densities. [ABSTRACT FROM AUTHOR]