Adsorption-Mediated Synthesis of Prussian Blue Nanoparticles and Nanocomposites for Electrochromic and Electrocatalytic Applications

: The relentless exploitation of natural resources has intensified the search for alternative and sustainable energy solutions. In this context, Prussian Blue (PB) has emerged as a promising material for energy-related applications. In this work, a facile in situ adsorption-based strategy was employed for the synthesis of Prussian Blue nanoparticles (PB NPs) with integrated bifunctionality. The approach utilized an N′ -[3-(trimethoxysilyl)propyl] diethylenetriamine (TPDT) silicate sol – gel (SSG) matrix, followed by the electrodeposition of gold nanoparticles (Au NPs) onto indium tin oxide (ITO) electrodes, yielding a PB@Au nanocomposite (ITO/TPDT-PB/Au). The fabricated electrodes were comprehensively characterized using UV – visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. The functional applicability of the electrodes was investigated with respect to electrochromic and electrocatalytic performance. In situ spectro-electrochemical studies of ITO/TPDT-PB electrodes revealed pronounced electrochromic behavior, demonstrating their potential utility in smart window applications. Furthermore, the electrocatalytic activity of ITO/TPDT-PB and ITO/TPDT-PB/Au electrodes was eval uated using oxygen (O₂) and hydrogen peroxide (H₂O₂) reduction as model reactions. The synergistic integration of PB and Au nanoparticles in the ITO/TPDT-PB/Au electrode resulted in a significantly enhanced and selective electrocatalytic response toward H₂O₂ reduction at −0.055 V, compared to O₂ reduction at −0.283 V. These findings underscore the potential of PB@Au nanocomposites for advanced energy and environmental applications.