Hydrogen detection based on Au-Pd core-shell systems

In this article we have studied the structure of Au-Pd core-shell nanoparticles, which is composed of a uniform Au inner core surrounded by Pd nanoparticles. This is done to a new ultrasensitive sensor with height performance characteristics, low-cost fabrication process for hydrogen detection. Hydrogen cannot be used like any other gas because of its explosive behavior at 4% concentration in the air and, to avoid any risk we need to control its concentration permanently. The Au– Pd core-shell nanoparticles (NPs) were synthesized according to a multi-reduction step method. The morphology, density, size, and structure of these nanoparticles can be controlled by the synthesis conditions. They were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The impact of Pd shell on the surface plasmon resonance (SPR) was investigated by finite difference time domain simulations (FDTD) and the absorption spectroscopy under different hydrogen concentrations ranging from 1% to 4%. We noticed a change in the optical behaviour and a shift of the SPR peak of our Au-Pd core-shell system towards the lowest wavelengths from the first hydrogenation dehydrogenation cycle.