Understanding H2 adsorption on mesoporous SnO2 nanospheres: a combined DFT and experimental study

Abstract Spherical tin oxide (SnO 2 ) material was successfully synthesized via a precipitation method, followed by a heat treatment that oxidized Sn 6 O 4 (OH) 4 to tetragonal SnO 2 (P42/mnm space group) with an average crystallite size of 10.326 nm. FESEM and TEM analyses confirmed the formation of agglomerated, spherical SnO 2 particles (29–85 nm). BET analysis revealed a mesoporous structure with a specific surface area of 76.071 m 2 g −1 and an average pore diameter of 10.913 nm. The sensor exhibited excellent selectivity and response to H 2 gas, achieving a rapid 1 s response and 63 s recovery at 200 °C for 500 ppm H 2 . Device stability was confirmed by consistent steady-state resistance (57–62 KΩ) and only a 0.13% reduction in response over 30 days. Computational results revealed that for H 2 adsorption on oxygen-pre-adsorbed SnO 2 facets, the adsorption energy values are –42.628 kcal mol −1 , –42.597 kcal mol −1 , –42.565 kcal mol −1 , and –42.440 kcal mol −1 for the (200), (211), (110), and (101) surfaces, respectively.