Ru-Doped CeO₂ Nanoparticles as Sensing Materials for the Detection of Formaldehyde

The surge in population has led to an increase in construction industries and other infrastructure developments, which has affected the environment by various means. These pollutants are harmful to the ecosystem and unhealthy for living organisms, including human lives. To address these issues, the envisaged sensing materials should have a greater surface area, low energy consumption, and a durable surface to increase gas molecule adsorption. The Ru-doped ceria oxide gas sensor detects formaldehyde gas over a wide range of 5–30 ppm at room temperature (RT). The impact of dopants on gas molecules and the quantity of the sensor material are investigated, where Ru-doped ceria oxide facilitates a high response to formaldehyde gas sensing. The current work provides a route to develop an RT formaldehyde gas sensor and exhibits the relationship between RuO 2 and Ru–CeO 2, indicating that more active sites are needed for sensing materials to exhibit a better sensing performance. The Ru-doped ceria sensor demonstrated the highest reproducibility, revealing a longer life of the sensor material. Efficient charge transfer is achieved, where the noble metal Ru is proven to swiftly effect the gas reaction on the surface. The as-fabricated sensor shows effective sensing at 20–50% RH, delivers a considerable signal at higher humidity, and detects an ultralow concentration of 10 ppb gas, which can dispel the problems of metal oxide gas sensors to some extent.