Synthesis of porous In2O3 microspheres as a sensitive material for early warning of hydrocarbon explosions†
Abstract
Efficient detection/monitoring of low-concentration C1–C3 aliphatic hydrocarbons (e.g., methane) is a challenging task, mainly due to their intrinsically low chemical reactivity and thereby weak sensing response. Herein we report the template-free synthesis of porous nanoparticle-assembled In2O3 microspheres that can serve as a highly sensitive material for C1–C3 detection. In particular, porous In2O3 microspheres with a BET surface area of 57 m2 g−1 are prepared through simple thermal treatment of an indium glycerolate precursor. The gas-sensing properties of the porous In2O3 material are evaluated by a series of C1–C3 hydrocarbons including methane (CH4), ethane (C2H6), propane (C3H8), ethylene (C2H4) and acetylene (C2H2). The porous In2O3 material has the ability to detect these gases with a rapid response (<10 s) in a wide concentration range from 200 ppm to 50 000 ppm (the lower explosion limit of methane). In the testing range, the logarithm of response shows a good linear dependency on the logarithm of gas concentration, demonstrating that the porous In2O3 material may be used for quantitative detection of C1–C3 hydrocarbons. Given the rapid response and high sensitivity below the explosion limit, this porous In2O3 material is promising to provide earlier warning against the explosion risk of hydrocarbon compounds.