In-situ construction of direct Z-scheme NiO/Bi2MoO6 heterostructure arrays with enhanced room temperature ether sensing properties under visible light irradiation

Light irradiation has emerged as a promising strategy to promote room temperature sensing of resistive-type semiconductor gas sensors recently. However, high recombination rate of photo-generated carriers and poor visible light response of conventional semiconductor sensing materials have greatly limited the further perfor-mance improvement. It is urgent to develop gas sensing materials with high photo-generated carrier separation efficiency and excellent visible light response. Herein, a novel direct Z-scheme NiO/Bi2MoO6 heterostructure arrays were designed and in-situ constructed on alumina flat substrate to form thin film sensors, which realized excellent room temperature gas response towards ether under irradiation of visible light for the first time, together with excellent stability and selectivity. Based on density functional theory calculation and experimental characterization, it was demonstrated that the construction of Z-scheme heterostructure could greatly promote the separation of photo-generated carriers and adsorption of ether. Moreover, the excellent visible light response characteristics of NiO/Bi2MoO6 could improve the utilization of visible light. In addition, the in-situ construction of array structure could avoid a series of problems caused by the conventional thick film devices. The work not only provides a promising guideline for Z-scheme heterostructure arrays in promoting the room temperature sensing performance of semiconductors gas sensors under visible light irradiation, but also clarifies the gas sensing mechanism of Z-scheme heterostructure at the atomic and electronic level.

Automated summary

Light irradiation is a promising strategy for room temperature sensing in semiconductor gas sensors, but the recombination rate of photo-generated carriers and poor visible light response of conventional sensing materials limits performance improvement. This study successfully developed a novel Z-scheme NiO/Bi2MoO6 heterostructure that showed excellent room temperature gas response towards ether under visible light irradiation. The heterostructure improved carrier separation and ether adsorption, and the visible light response of NiO/Bi2MoO6 enhanced light utilization. The in-situ construction of the heterostructure array also minimized problems associated with traditional thick film devices. This work provides important insights into the room temperature sensing performance and gas sensing mechanism of Z-scheme heterostructures.