Enhanced Photocatalytic Activity of Exfoliated WS₂ Nanosheets

Tungsten disulfide (WS₂) nanosheet is a promising material for potential photocatalysis applications due to its large surface area and novel electronic properties. The economic and large-scale production of WS₂ nanosheets is a fundamentally important step to realize its future applications. The exfoliation of nanosheets in a solution from their layered bulk counterpart using high-intensity ultrasound waves has proven to be a cost-effective method to produce nanosheets with high yield. Here, we show the production of WS₂ nanosheets increases significantly if layered WS₂ bulk powder is ball-milled before the ultrasonication process. We find the ball milling assisted sonication increases nanosheets’ yield by 50% compared to the combined yield if the bulk crystal is solely ball milled or sonicated. The optical absorption studies show the high quality of WS₂ nanosheets with the yield as high as 6.4%. The photodegradation kinetic studies show the decomposition rate of methyl orange with WS₂ nanosheets is at least 1.3 times higher than with WS₂ powder, suggesting nanosheets’ enhanced photocatalytic activity.