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Molybdenum disulfide has received great attention as a promising non-noble catalyst for electro-catalyzed hydrogen evolution reaction. The active sites originated from the limited edge of crystalline molybdenum disulfide is the key to restrict its HER performance. To increase the active sites of molybdenum disulfide through the heteroatom doping with effective synthetic strategy has become the focus of activity improvement. Herein, a facile and efficient strategy was adopted to synthesize oxygen-doped molybdenum sulfide catalyst by utilizing thiourea and sodium molybdate as precursors. It was found that the number of active sites could be regulated by controlling the dosage ratio of thiourea to sodium molybdate. The doped oxygen and abundant S endows molybdenum sulfide a great deal of lattice disorder or defects, thus providing adequate active sites. When the optimized ratio of thiourea to sodium molybdate (40:1), the double layer value of oxygen-doped molybdenum sulfide reached 34.14 mF/cm2 (mass loading on glassy carbon electrode was 0.142 mg/cm2) which is considered to be proportional to the electrochemical active area. Raman spectroscopy and X-ray photoelectron spectroscopy confirmed the presence of Mo–O bond and bridging S22− bonds which endows molybdenum sulfide with a great deal of lattice disorder or defects, thus providing plentiful active sites.

Green waste compost (GWC) is a value-added product generated by the composting of urban green waste. Although GWC could potentially be used as a growth medium for soilless culture of plants, GWC alone has high salinity, high pH, and other undesirable physicochemical properties. In the current study, we therefore assessed how addition of vermiculite (VMT: 0, 3.5, and 7%) and humic acid (HA: 0, 0.5, and 1 g/100 g) affected the physicochemical properties of GWC and its use as a growth medium for cornflower (Centaurea cyanus L.). GWC modified by the combination of 3.5% VMT and 0.5 g/100 g HA had the best physicochemical properties (bulk density, porosity, water holding capacity, electrical conductivity, pH, and nutrient content) and resulted in the best growth of cornflower in terms of plant height, maximum root length, flower number, and biomass. The results therefore indicate that GWC modified by 3.5% VMT and 0.5 g/100 g HA powder is an excellent soilless growth medium.