Optical hydrogen sensors based on silica self-assembled mesoporous microspheres

A mesoporous microsphere with excellent optical performance is built by silica (SiO2) nanoparticles self-assembly technique. This optical device shows a sensitivity to the hydrogen gas (H-2) in surrounding environment. The Palladium (Pd) nanoparticles are selectively introduced to heighten the sensitivity. The fabrication of these sensors and their sensing mechanisms are introduced and discussed. According to the experimental results, whispering-gallery modes of pure SiO2 sensor shift linearly at a rate of similar to 110 pm/% with an H-2 concentration between 0.15% and 45%. In comparison, the Pd-decorated sensor shows a much higher sensitivity of similar to 1.33 nm/% for trace-gas detection. Such sensors, as a kind of lab-on-fiber devices, are very advantageous for on-line monitoring of H-2 leakage. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.