Highly Porous CeO₂ Nanoparticles for Real-Time Hydrogen Gas Sensing Application at Room Temperature

Hydrogen (H₂) is widely recognized as a clean and sustainable energy source, but its highly flammable nature emphasizes the crucial need for efficient, room-temperature (RT) H2 gas sensors. In the present study, cerium oxide (CeO2) nanoparticles were synthesized using a facile solution combustion synthesis (SCS) and explored for H2 gas sensing at RT. The synthesized CeO2 nanoparticles were comprehensively characterized to evaluate their structural, morphological, optical and surface properties. The sample exhibited highly porous morphology with mesoporous structures, has a crystallite size of 14.5 nm with an average particle size of 46 nm, a high surface area of 142 m2/g and a lower bandgap of 2.28 eV. These characteristics enabled enhanced gas adsorption and rapid surface reactions on the material. The CeO2-based sensor demonstrated excellent sensitivity at RT, exhibiting a notable response of 4% even at a low concentration of 1000 ppm H2 gas. The peak response of 52.3% was observed for 10000 ppm of H2 gas and the results obtained showed linear response with increasing concentrations. The sensor exhibited brilliant repeatability, long-term stability over 200 days, high selectivity and the limit of detection of 106 ppm at RT. The enhanced sensing performance is attributed to the synergistic effect of mesoporosity, high surface area and favourable Knudsen diffusion within the porous network of CeO2. This study establishes SCS-derived CeO2 as a promising material for low-cost, energy-efficient and real-time H2 sensing at ambient conditions.