Surface Engineering of MoS2 via Laser‐Induced Exfoliation in Protic Solvents

Abstract With excellent performance in the hydrogen evolution reaction (HER), molybdenum disulfide (MoS 2 ) is considered a promising nonprecious candidate to substitute Pt‐based catalysts. Herein, pulsed laser irradiation in liquid is used to realize one‐step exfoliation of bulk 2H‐MoS 2 to ultrastable few‐layer MoS 2 nanosheets. Such prepared MoS 2 nanosheets are rich in S vacancies and metallic 1T phase, which significantly contribute to the boosted catalytic HER activity. Protic solvents play a pivotal role in the production of S vacancies and 2H‐to‐1T phase transition under laser irradiation. MoS 2 exfoliated in an optimal solvent of formic acid exhibits outstanding HER activity with an overpotential of 180 mV at 10 mA cm −2 and Tafel slope of 54 mV dec −1 .