Surface oxygen vacancies actuated MoO3/CuMoO4 self-assembled microspheres for highly selective triethylamine detection

The construction of tunable oxygen vacancies on the surface of materials has become an emerging approach to develop excellent gas sensitivity, in spite of the critical need for the influencing mechanism. In this paper, novel MoO3/CuMoO4 self-assembled microspheres with superior gas-sensing performance to triethylamine (TEA) have been fabricated by a simple solvothermal route. The introduction of Cu2+ plays a key role for the surface defects and morphological evolution of MoO3-based composites. The sensors based on MoO3/CuMoO4 microspheres exhibit an optimal response of 240.1 toward 100 ppm TEA with fast response and recovery time (45/15 s) at a low operating temperature of 300 °C, together with the low detection limit of 500 ppb, good long-term stability and reliability, and remarkable selectivity for TEA. Actually, abundant oxygen vacancies as active sites greatly contribute to the increasing surface chemisorbed oxygen. The enhanced gas-sensing mechanism can be mainly ascribed from the combination of the formation of MoO3-CuMoO4 heterojunctions, surface oxygen vacancies, and the self-assembled microstructure for the improved electron transfer behavior. The present work provides a new insight into the design of surface oxygen vacancies actuated gas sensors with unique surface/interface reactive process and transport mechanism.