Diluting the Electric Supply of Surface Selenium Species to Realize Enhanced Hydrogen Monitoring in Agriculture

Abstract

Electron state of catalyst surface is crucial to optimize the adsorption/intermediate state of gas molecules during the sensing reaction. Herein, we develop an electron-dilution strategy by introducing Pd/Pt species into semiconductor ZnSe to construct electron-deficient Se surface, exhibiting excellent H₂ sensing performances. It is found that different metal doping can induce remarkable electric environment changes of Se atoms. For example, compared with Pd, Pt display stronger electronic dilution ability to adjacent Se atoms. X-ray photoelectron spectroscopy (XPS) characterizations further prove that the doping of Pd/Pt will induce the generation of the electron-deficient Se sites, appearing a new and high binding energy state. Furthermore, the density functional theory (DFT) calculations show that the deficient Se sites on the Pt-ZnSe surface could reduce the level of anti-bonding orbital filling, thus enhancing the stability of the Se-Hads bond and strengthening the H₂ adsorption. As a result, the Pt-ZnSe based micro-electromechanical systems (MEMS) gas sensors exhibit high response value of 3.22 to 10 ppm H₂ at low operation temperature of 145 °C. Inserting the Pt-ZnSe MEMS sensors array into multifunctional wireless sensing device, it can realize real-time H₂/temperature/humidity monitoring and cloud data transmission for hydrogen agriculture on production, preserving and storing crop.