Hydrogen peroxide assisted sol-gel synthesis of 2D SnO₂ for H₂ detection in low concentration range

This work presents a novel, chlorine-free route for the synthesis of two-dimensional (2D) SnO₂ via a hydrogen peroxide-assisted sol-gel method. Ammonium peroxostannate sol is used as a precursor, effectively eliminating chlorine impurities through peroxo-complex formation. Graphene oxide serves as a sacrificial template forming a 2D morphology. The obtained SnO₂-2D material is characterized by an ultra-small crystallite size of ∼5 nm and a high specific surface area (68 m²/g), which can withstand high temperature annealing at 500 °C. The SnO₂-2D material demonstrates excellent performance as a hydrogen sensor, showing a high response (S = 8.9 towards 20 ppm H₂ at 250 °C with LOQ = 270 ppb in dry air) and maintaining significant activity under humid conditions (S = 4.5 towards 20 ppm H₂ at 400 °C with LOQ = 270 ppb in humid air at RH = 50 %).