CaFe2O4/CaO Composite Nanomaterials with Enhanced Surface Area for High-Performance Hydrogen Gas Sensing

Hydrogen gas detection with precision is becoming an essential for the safe production and functioning of hydrogen. Present work reports the synthesis of Pure phase CaFe 2 O 4 and Composite nanomaterial CaFe 2 O 4 /CaO via hydrothermal route and their exploitation for hydrogen gas sensor. X-ray diffraction analysis reveals Orthorhombic CaFe 2 O 4 , also highlights cubic CaO phase formation in composite with average crystallite size 23.7 nm and 40.7 nm, respectively. High-resolution transmission electron microscopy confirms lattice fringes of orthorhombic CaFe 2 O 4 phase and Cubic phase CaO in composite, revealing particle size of 17 nm. Selected Area Electron Diffraction confirmed polycrystalline nature of fabricated composite. UV-Visible Spectroscopy analysis exhibited enlargement in band gap energy of composite. Screen printing approach was acclimated to fabricate thick films to explore gas sensing performance. Surface topography and elemental composition of pristine CaFe 2 O 4 and composite CaFe 2 O 4 /CaO thick films were analysed using Field emission scanning electron microscopy with Energy dispersive X-ray spectroscopy technique. Fabricated composite exhibited enhanced specific surface area 21.231 m 2 /g, in contrast to CaFe 2 O 4 as investigated by Brunar-Emmett-Teller characterization technique. Composite CaFe 2 O 4 /CaO thick film demonstrates greatest response of 97.68% towards 500 ppm H 2 gas with rapid response time of 0.9 s and short recovery time 5.4 s at lower working temperature than Pristine CaFe 2 O 4 . Incorporating CaO into pristine CaFe 2 O 4 , sensing performance is enhanced significantly. Response time for H 2 gas and working temperature of composite is reduced, which might be attributed to lower activation energy.