One-Step Electrosynthesis of Polyoxometalate-Based Organic-Inorganic Hybrid Polymers and Their Confinement in...

The development of organic-inorganic hybrid polyoxometalates (POMs) covalently linked to conducting polymers is an effective strategy to preserve their electrochemical accessibility upon immobilization. However, conventional approaches typically involve multistep syntheses, resulting in low POM loading and limited nanoscale control. Here, we report a one-step electrosynthetic approach to generate a POM-rich conducting polymer via electropolymerization of a bifunctional precursor, PW₁₁-(ANI)₂, bearing two aniline moieties. Electropolymerization is first demonstrated on bare indium-tin oxide (ITO) electrodes and then extended to the formation of poly(PW₁₁-ANI) nanofilaments confined within vertically aligned mesoporous silica films (VMSF). The process is initiated by electrochemical oxidation of the aniline groups, generating radical cations that couple to form the hybrid polymer, as evidenced by the progressive growth of reversible POM-centered voltammetric signals. The resulting surface-confined films exhibit good adhesion, further enhanced by a preliminary electrografting step using the monodiazonium derivative PW₁₁-(ANI)(diaz). Both films and nanoconfined structures are electroactive and display electrocatalytic activity toward nitrite reduction, which is enhanced under confinement. These results demonstrate the potential of aniline-functionalized POMs as versatile building blocks for electroactive hybrid materials in sensing, electrochromic, and energy storage applications.