ABSTRACT

Chemical reactions simulation in detecting hydrogen gas (H₂) on Pt₈₀Au₁₄Ti₆ sensor surface based on work function change (Δɸ) has been conducted. The simulation result is compared with laboratory results of detecting H₂ gas. Three chemical reactions contained three coverages, H coverage (θ_H), O coverage (θ_O), and H₂O coverage (θ_H2O). The simulation was run using MATLAB. This research can find the reaction parameter values such as the Arrhenius coefficient of H₂O forming reaction on Pt (υf3Pt), H₂O forming reaction on Au (υf3Au), i.e., H₂O dissociation on Au (υf3Au ), O₂ desorption on Ti (υd2Ti), H₂O forming reaction on Ti (υf3Ti), and H₂O dissociation on Ti (υf3Ti), i.e., 7.5×10¹⁴ s^–1, 9.85×10¹⁵ s^–1, 3.25×10¹⁵ s^–1, 7.11×10¹⁵ s^–1, 3.425×10¹⁵ s^–1 and 2.725×10¹⁵ s^–1, respectively. The simulation results also have the same trend as the laboratory results. However, the contact potential difference (CPD) simulation result, i.e., –240 mV, is not the same as the laboratory result, (–297± 9) mV. In addition, this simulation also obtained approximation coverage for atoms/molecules on PT₈₀Au₁₄Ti₆ surface, i.e., θ_H = 0.665154 Mono Layer (ML); θ_O = 1.5621× 10^–6 ML; and θ_H2O = 5.41676 ×10^–5 ML.

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