Pd nanoparticle-modified FeWO4 hollow spheres for highly selective hydrogen sulfide and acetone detection

The development of a highly responsive and selective gas sensor for volatile organic compounds, such as hydrogen sulfide and acetone, is still required. In a recent study carried out by Chen et al., FeWO₄ hollow spheres modified with Pd nanoparticles were synthesized using ammonium phosphotungstate hydrate dodecahedra as sacrificial templates followed by liquid-phase reduction. The morphologies, microstructures, and gas-sensing characteristics of as-prepared sensing nanomaterials have been investigated. The tiny Pd nanoparticles are well anchored on the FeWO₄ hollow spheres. At the working temperature of 280 °C, the 3 wt.% Pd/FeWO₄ hollow sphere sensor exhibits higher sensitivity to acetone and ethanol gasses than unmodified FeWO₄ hollow spheres, as well as good repeatability and fast response. Meanwhile, the 3-Pd/FeWO₄ hollow sphere sensor at a low operation temperature of 25 °C exhibits a high response of 2.3–10 ppm hydrogen sulfide with excellent selectivity, which is much stronger than that of the FeWO₄ sensor. The outstanding performance of the 3-Pd/FeWO₄ hollow sphere sensor is attributable to its exceptional hollow microstructure with a high specific surface area and the catalytic properties of Pd nanoparticles.

This work, published by Frontiers of Materials Science, therefore advances beyond prior tungstate sensors by coupling hollow architecture and Pd catalysis to achieve temperature-programmed dual selectivity. The strategy offers a general design route for multi-gas sensing using a single material system.