Screening promising TM-doped CeO2 monolayer for formaldehyde sensor with high sensitivity and selectivity

Developing convenient, fast-response and high-performance formaldehyde detection sensor is significant but challenging. Herein, two CeO2 phases (Fm3¯m and P42/mnm), three facets (CeO2(100), CeO2(110) and CeO2(111)) and three adsorption sites (top, bridge and hollow) are selected as substrate to interact with formaldehyde. Twenty-eight candidated transition metals (TM) are doped on CeO2 surfaces to investigate the performance of detecting formaldehyde by density functional theory. It shows that (i) CeO2 in a cubic fluorite structure with the space group Fm3¯m is suitable for formaldehyde adsorption compared with P42/mnm; (ii) TM-CeO2(100) (TM = Au, Hf, Nb, Ta, Zr) are considered as candidated materials to absorb formaldehyde ascribed to lower adsorption energies. The d-band center, partial density of states, charge density difference and electron localization function are employed to clarify the mechanism of TM-doped CeO2 improving the performance of formaldehyde adsorption. It obviously displays that TM doped CeO2(100) changes the d orbit and rearranges electrons resulting in the superior ability to the adsorbed formaldehyde. This work provides theoretical guidance and experimental motivation for the development of novel formaldehyde sensor based on metal oxide semiconductor materials.