Novel earth-abundant metal sulfate-containing high entropy sulfides, FeNiCo-CrXS 2 (where X = Mn, Cu, Zn, or Al), are synthesized via a two-step solvothermal method. It is shown that sulfate-containing FeNiCoCrMnS 2 exhibits superior oxygen evolution reaction (OER) activity with an exceptionally low overpotential of 199, 246, 285, and 308 mV at current densities of 10, 100, 500, and 1000 mA cm -2 , respectively, and surpassing its unary-, binary-, ternary-, and quaternary-metal counterparts. The electrocatalyst yields exceptional stability after 12 000 cycles and 55 h of durability even at a high current density of 500 mA cm -2 . Various in situ and ex situ analyses are used to investigate the self-reconstruction of the sulfides during the OER for the first time. The resulting metal (oxy)hydroxide is believed to be the true active center for OER. The remaining sulfate also contributes to the catalytic activity. Density function theory calculation is in good agreement with the experimental result. The extraordinary OER performance of the high entropy sulfide brings a great opportunity for desirable catalyst design for practical applications.
ZnO nanowires were produced using an electrospinning method and used in gas sensors for the detection of ethanol at 220 °C. This electrospinning technique allows the direct placement of ZnO nanowires during their synthesis to bridge the sensor electrodes. An excellent sensitivity of nearly 90% was obtained at a low ethanol concentration of 10 ppm, and the rest obtained at higher ethanol concentrations, up to 600 ppm, all equal to or greater than 90%.
Single crystalline zinc oxide (ZnO) nanowires were synthesized on sputter‐deposited ZnO seed layers via hydrothermal reactions in an equimolar (20 mM) aqueous solutions of Zn(NO3)2·6H2O and C6H12N4 at 90°C. The sputter‐deposited ZnO seed layers were prepared to exhibit different crystalline structures in order to examine their effects on the growth of ZnO nanowires. It was found that the nanowire diameter depends on the size of the (002) grains of the seed layer. This is attributed to the epitaxially growth of the nanowires from the columnar grains of the seed layer which is shown by the TEM analysis.
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