This article reports the development of oxidative precipitation (OP) method for synthesis of Co(3)O(4) as an environmental catalyst and comparison of its performance with that of obtained from conventional sol gel combustion (SG) method and industrial Pt/γ-Al(2)O(3) in remediation of toluene from air. Catalytic studies were carried out in a fixed bed reactor at 100-350°C under atmospheric pressure. Co(3)O(4) (OP) showed the highest activity in combustion of toluene. The half conversion temperature of toluene (T(50%)) was 160, 258, and 229°C on Co(3)O(4) (OP), Co(3)O(4) (SG) and Pt/γ-Al(2)O(3), respectively. The higher activity of Co(3)O(4) (OP) was ascribed to nanostructure and reducibility of catalytic sites at lower temperatures, approved by TPR results. The study confirmed that preparation method has a large influence on the chemical-physical properties and activity of the catalyst. The study indicated that oxidative precipitation method could be a promising method to synthesize environmental catalysts considering the simplicity and needless to calcine catalyst at higher temperatures.

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Due to the favorable properties of two-dimensional materials such as SnS2, with an energy gap in the visible light spectrum, and InSe, with high electron mobility, the combination of them can create a novel platform for electronic and optical devices. Herein, we study a tunable gain SnS2/InSe Van der Waals heterostructure photodetector. SnS2 crystals were synthesized by chemical vapor transport method and characterized using X-ray diffraction and Raman spectroscopy. The exfoliated SnS2 and InSe layers were transferred on the substrate. This photodetector presents photoresponsivity from 14 mA/W up to 740 mA/W and detectivity from 2.2 × 108 Jones up to 3.35 × 109 Jones by gate modulation from 0 V to +70 V. Light absorption and the charge carrier generation mechanism were studied by the Silvaco TCAD software and the results were confirmed by our experimental observations. The rather high responsivity and visible spectrum response makes the SnS2/InSe heterojunction a potential candidate for commercial visible image sensors.