Two-dimensional transition-metal dichalcogenides (TMDs) possess interesting catalytic properties for the electrochemical-assisted hydrogen-evolution reaction (HER). We used niobium diselenide (NbSe2) as a representative TMD. and prepared single-layer NbSe2 porous nanosheets (PNS) by a double-sonication liquid-phase exfoliation. with H2O2 as a pore-forming agent. https://halohealthcarers.shop/product-category/face-masks/