Tellurium nanostructures were utilized as a gas sensing material to detect hydrogen sulfide gases at room temperature. Te nanostructures were synthesized by a galvanic displacement reaction of nickel particles as a sacrificial material. The morphologies of Te hollow spheres and branched Te hollow spheres were controlled by the concentration of the employed HTeO2+. The branched Te hollow spheres were formed by additional nucleation and growth of Te branches on the surface of Te hollow sphere in high concentration of HTeO2+. Compared to the room temperature sensing properties of Te hollow spheres, the branched Te hollow spheres showed the significantly enhanced sensitivity. The improved performance in the branched Te hollow spheres is attributed to the increased specific surface area, larger variation of hole accumulation layer for carrier transport, and especially drastic variation of electrical resistance in the increased junction potentials between the branches. Additionally, the branched Te hollow spheres showed strong selectivity for H2S over other gases such as NO2, SO2, and H2, making them highly effective for detecting H2S at room temperature.
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