CeO₂ and Nb₂CT_x heterojunction for efficient room-temperature NH₃ detection

Although metal oxides are attractive to gas sensing, the low response, high working temperature, and poor selectivity hamper widespread applications. Herein, a room-temperature NH₃ gas sensor constructed with CeO₂ nanoparticles functionalized Nb₂CT_x MXene is designed and demonstrated. Compared to CeO₂, the response to NH₃ increases by 4 times. The other merits include a low detection limit, excellent repeatability, long-term stability, as well as rapid response and recovery. The enhanced NH₃ sensing performance can be attributed to several factors. Firstly, the unique layered structure of CeO₂/Nb₂CT_x composites increases the surface area to improve the adsorption and diffusion ability of NH₃. Secondly, introduction of Nb₂CT_x could promote formation of oxygen vacancy in CeO₂, increasing the density of active sites and promoting adsorption of NH₃. Thirdly, a heterojunction is formed at interface to boost electron transfer and the sensing capability. The results reveal a novel strategy to develop metal oxide and MXene heterojunctions for sensitive and reliable detection of NH₃. © 2025 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.