One-step electrosynthesis of nanostructured Mn-V oxides with tunable redox characteristics

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The rational design of nanostructured mixed-metal oxides through scalable and controllable fabrication methods remains a central challenge in nanomaterials science. In this work, we present a one-step, substrate-free electrosynthesis strategy that enables the direct formation of nanostructured Mn-V mixed oxides with tunable physicochemical characteristics. By systematically adjusting the applied current and precursor ratios, the method provides precise control over phase composition, crystallite size within the nanoscale regime, degree of amorphous vs. crystalline order, and textural parameters, allowing access to material architectures that are not attainable through conventional wet-chemical or high-temperature routes. A series of MnO2 and Mn-V mixed oxides, as well as V2O5 for comparative purposes, were prepared under galvanostatic conditions without any further thermal treatment. Pure MnO2 samples exhibited a mixture of ε- and γ-phases, with lamellar morphologies and outstanding surface areas. However, the incorporation of vanadium induced significant structural and morphological changes, including amorphization and the formation of V-based crystalline domains at higher loadings. Furthermore, catalytic tests showed that all materials achieved complete glucose conversion, while the Mn-V oxides significantly improved selectivity towards formic acid. Specifically, the MnV_5:1 sample exhibited the best performance, along with a notable suppression of CO2 formation. The enhanced performance could be attributed to a synergistic Mn-V redox interaction that promotes controlled oxidation pathways and stabilizes intermediates. These findings demonstrate the potential of electrosynthesis as a tunable method, additionally offering sustainability, time-efficiency, cost-effectiveness, and reproducibility, for developing advanced and promising sustainable materials.