Facet-Controlled Truncated-Octahedral Pd Nanocrystal/Mesoporous SnO2 Nanocomposites for Low-Temperature, High-Sensitivity Hydrogen Sensing

Abstract

Facet-engineered noble metal nanocrystals coupled with mesoporous oxide supports offer a powerful route toward high-performance hydrogen sensing. In this work, truncated octahedral Pd nanocrystals (TRD-Pd) exposing {111} and {100} facets were synthesized via a halide-assisted facet-selective growth method and integrated with mesoporous tin(IV) oxide (m-SnO2). Structural, morphological, and spectroscopic characterization, including electron microscopy, XRD, FTIR, BET, UV–Vis, and Raman spectroscopy, confirmed the well-defined Pd morphology, good dispersion, and high-surface-area mesoporous framework. Unlike conventional SnO2-based hydrogen sensors, which typically require operating temperatures above 250 °C, the TRD-Pd/m-SnO2 nanocomposite exhibits a pronounced hydrogen response at significantly lower temperatures, achieving peak performance at 150 °C. This low-temperature operation, combined with a ~20-fold enhancement in hydrogen response compared with pristine SnO2, a 14.3 s response time, and a 2.0 ppm detection limit, highlights the catalytic advantage of facet-controlled Pd nanocrystals integrated with mesoporous SnO2. The synergy between engineered Pd facets and the mesoporous semiconductor matrix establishes a promising platform for low-temperature hydrogen detection and provides a potential design strategy for next-generation gas sensors.

Keywords

• Chemiresistive gas sensors
• Pd nanocrystals
• Facet engineering
• Mesoporous semiconductor oxides
• Hydrogen sensing
• Metal–semiconductor interfaces

Ethical Statement

Ethics committee approval was not required for this study because of there was no study on animals or humans.

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