Facile Fabrication of ZnO-ZnFe2O4 Hollow Nanostructure by a One-Needle Syringe Electrospinning Method for a High-Selective H2S Gas Sensor

Herein, a facile fabrication process of ZnO-ZnFe2O4 hollow nanofibers through one-needle syringe electrospinning and the following calcination process is presented. The various compositions of the ZnO-ZnFe2O4 nanofibers are simply created by controlling the metal precursor ratios of Zn and Fe. Moreover, the different diffusion rates of the metal oxides and metal precursors generate a hollow nanostructure during calcination. The hollow structure of the ZnO-ZnFe2O4 enables an enlarged surface area and increased gas sensing sites. In addition, the interface of ZnO and ZnFe2O4 forms a p-n junction to improve gas response and to lower operation temperature. The optimized ZnO-ZnFe2O4 has shown good H2S gas sensing properties of 84.5 (S = Ra/Rg) at 10 ppm at 250 ∘C with excellent selectivity. This study shows the good potential of p-n junction ZnO-ZnFe2O4 on H2S detection and affords a promising sensor design for a high-performance gas sensor.

PEMBUATAN SISTEM VAKUM OTOMATIS GAS H2S BERBAHAN TiO2-Ni/Al2O3 TERKONEKSI ARDUINO UNO PADA LABORATORIUM KIMIA

Research has been carried out on the H2S gas sensor made of TiO2-Ni/Al2O3 which is connected to an automatic vacuum. The results showed that the optimum conditions for the variation of Ni doping metal levels were 20 mg / gram TiO2. The semiconductor material synthesis method used the sol gel method with TTiP precursor which was made at pH 7. Coating of the sol gel solution on the Al2O3 substrate used a dip coater with a decrease speed of 1 cm / minute and was carried out 7 times of immersion. The characterization of synthetic results used UVVis, XRD, FTIR and SEM-EDX. The band gap value resulting from Ni doping is 2.75 eV from 3.2 eV, XRD identification shows that TiO2 is anataseic and detected at 2θ. FTIR data also supports XRD results with detection of TiO2, Ni-O, NiTiO3, Ti-O-Ni, and Ti-O-Ti groups. TiO2-Ni / Al2O3 sensor test results are very sensitive and selective to H2S gas. Arduino Uno sensor and microcontroller connectivity can change the unit of resistance into a unit of ppm concentration and can drive the exhaust (vacuum) automatically in the laboratory room or chemical storage space when there is H2S.

Synthesis and H2S Gas Sensing Characteritics of Nanostructured V2O5

In this study, V2O5 nanomaterials were successfully synthesized by a facile hydrothermal method and tested for application in preparing toxic H2S gas sensor. SEM image shows that the material has the shape of nanoplates with different sizes ranging from 100 to 500 nm. The XRD pattern shows that the material has a single phase of Orthorhombic crystal of V2O5. The results of the gas sensitivity survey show that the material good respond to H2S at low concentrations (2.5-20 ppm) with relatively fast response and recovery time. This study demonstrates the potential of application of V2O5 material in H2S gas sensors.