Computational Design of Alloy Nanostructures for Optical Sensing of Hydrogen

Pd nanoalloys show great potential as hysteresis-free, reliable hydrogen sensors. Here, a multiscale modeling approach is employed to determine optimal conditions for optical sensing using the Pd–Au–H system. Changes in pressure translate changes content and eventually spectrum. At single particle level, shift of plasmon peak position with concentration (i.e., “optical” sensitivity) approximately constant at 180 nm/cH nanodisk diameters ≳100 nm. For smaller particles, sensitivity negative increases decreasing diameter, due emergence second originating from coupling between localized surface interband transitions. In addition tracking position, onset extinction well fixed wavelengths considered. We carefully compare simulation results experimental data assess sources discrepancies. Invariably, suggest that there an upper bound cannot be overcome by engineering composition and/or geometry. While alloy has limited impact on sensitivity, it can strongly affect H uptake consequently “thermodynamic” detection limit. shown how latter improved compositional even substantially enhanced via formation ordered phase synthesized higher partial pressures.