Directly anchoring non-noble metal single atoms on 1T-TMDs with tip structure for efficient hydrogen evolution

Owing to tip effect can introduce localized enhanced electric field and reduce interfacial energy barrier, design of atomic tip structure in single-atom catalysts (SACs) may be a fascinating strategy to further improve its electrocatalytic activity. However, conventional synthesis methods, such as defect-trapping or substitution, only lead to the formation of planar geometry of SACs without tip atoms. Good conductive 1T-TMDs with electrocatalytically active basal plane can provide platform to directly stabilize single atoms (SAs) on the top sites of its surface to form atomic tip structure. Herein, a universal Laser-molecular beam epitaxy (L-MBE) method for precisely controlling non-noble metal SAs directly immobilizing on the Cr top site of 1T-CrS2 metallic basal plane is developed. In case of Mo, the Mo SAs@1T-CrS2 with single-atom tip structure can exhibit enhanced electric field surrounding Mo atoms and an almost zero hydrogen adsorption free energy, resulting in superior HER performance together with high stability. This work provides a general way to design varieties of SACs in widely catalytic application.