Hydrogen sensing by localized surface plasmon resonance in colloidal solutions of Au-WO3-Pd

Nowadays, hydrogen has attracted significant attention as a next generation clean energy source. Hydrogen is highly flammable, so detection of hydrogen gas is required. Gold nanoparticle based localized surface plasmon resonance (LSPR) is an advanced and powerful sensing technique, which is well known for its high sensitivity to surrounding refractive index change in the local environment. We put particular focus on how LSPR of gold nanoparticles can be used to sense hydrogen gas. Additionally, metal oxides are generally used as materials for high sensitivity and fast response H2 sensors. Therefore, we used both an Au and WO3 colloidal with a PdCl2 solution added as a hydrogen catalyst. In this work, colloidal WO3 nanoparticles were synthesized by an anodizing method and Au NPs were obtained by pulsed Nd:YAG laser ablation. The gold NPs showed a LSPR absorption band over the visible and near infrared region. When Au nanoparticles were added to the mixture of WO3 and PdCl2, the plasmon peak of Au nanoparticles shifted to a longer wavelength in the presence of hydrogen gas. Structural, morphological and optical properties of colloids were investigated by using a XRD, TEM and UV-Vis spectrophotometer, respectively.