Density Functional Theory Study of P-Doped Co₃O₄(111) Facets for HCHO Adsorption: Implications for Metal Oxide Semiconductor Gas Sensors

Abstract

Volatile organic compounds (VOCs) pose a significant threat to human health, and it is essential to develop advanced VOC gas sensors by understanding the mechanisms. Metal oxide semiconductor gas sensors have the advantages of high sensitivity, high-temperature resistance, stability, and safety. The rational design of crystal facets and doping components can improve the sensing properties. However, the time-consuming experimental optimization of the sensor design has tremendously inhibited the development of the new sensing material. Nevertheless, density functional theory (DFT) calculations shined a light on the fundamental understanding of the sensing mechanism at the molecular level and accelerated the sensor design process. In this study, we used DFT calculations to investigate the sensing properties of the P-doped Co 3 O 4 (111) surface toward methanol, methane, formic acid, water, and formaldehyde. Results showed that P doping changed the surface electronic distribution, increased the charge transfer of HCHO, and enhanced the adsorption energy of other molecules. The significant difference in adsorption energy between H 2 O and HCHO indicates that the P-doped surface exhibits certain antihumidity properties in HCHO sensing. Our work broadens the application of P-doped Co 3 O 4 (111) in the VOC gas-sensing field and provides a theoretical basis for designing metal oxide semiconductor gas sensors.

Electrocatalytic Activity Enhancement of Multifunctional Co3O4 Nanorods for Glucose Sensing and Oxygen Evolution Reaction

“…Electrocatalytic activity is intricately linked to the adsorption and desorption capabilities of active sites regarding reaction intermediates. , The Sabatier principle underscores the necessity for an optimal balance in electrocatalyst strength, avoiding extremes in substance absorption. , Hence, optimizing the free energy associated with adsorption and desorption processes can improve intrinsic catalytic activity . Previous experiments have elucidated that this interaction between metal sites and carriers results from local electron distribution and the positioning of the metal atom d-band. , Theoretically, the interaction between the adsorbent’s valence state and the metal atom’s d state involves the formation of bonding and antibonding states, with electron filling closely linked to the energy state’s position relative to the Fermi level .…”