SCHEDULED MAINTENANCE
Mesoporous amorphous Al2O3/crystalline WO3 heterophase hybrids for electrocatalysis and gas sensing applications†
‡a
Yonghui
Deng
*a
Abstract
In this study, a versatile multicomponent co-assembly strategy is developed to rationally construct ordered mesoporous amorphous Al2O3/crystalline WO3 heterophase materials (denoted as mAl2O3/WO3). These materials exhibit excellent performance as electrocatalysts in hydrogen evolution reaction (HER) at high Al2O3 contents and as gas sensors in acetone detection at low Al2O3 contents. X-ray absorption fine structure spectroscopy reveals an unexpected local phase transition of the framework from γ-WO3 to metastable ε-WO3 and lattice distortion, which accounts for their application performances. Compared with commercial WO3 powders and mesoporous WO3, the mAl2O3/WO3 hybrid materials exhibit a high cathodic current density of 100 mA cm−2 at an overpotential of −230 mV and a low Tafel slope (52 mV dec−1), close to that of expensive commercial 20% Pt/C (−219 mV and 48 mV dec−1), and they also possess high alkali-stability for even 10 000 cyclic voltammetric sweeps. Thanks to the synergic effect between the catalytic ability of Al2O3 and the strong interfacial interaction of WO3 toward acetone molecules (a typical biomarker for diabetes), the mAl2O3/WO3 nanocomposites with low contents of Al2O3 (<2 wt%) exhibit superior sensing performance toward acetone with excellent selectivity and higher responses even at low concentrations as compared with mesoporous WO3. The concept about designed synthesis of such mesoporous amorphous/crystalline nanocomposites with dual functions at different content ratios holds great promise in development of novel advanced functional materials.
- This article is part of the themed collection: 2019 Journal of Materials Chemistry A HOT Papers
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