Rapid laser synthesis of surfactantless tantalum‐based nanomaterials as bifunctional catalysts for direct peroxide–peroxide fuel cells

Abstract

<p>Efficient and durable electrocatalysts are instrumental in enabling next-generation fuel cell technologies. At present, expensive precious metals are used as state-of-the-art catalysts. In this report, cost-effective nanosized tantalum-based alternatives are synthesized for the first time via a green and scalable laser pyrolysis method as bifunctional catalysts for direct peroxide–peroxide fuel cells. This rapid laser pyrolysis strategy allows for the production of nanoparticles at a laboratory scale of grams per hour, compatible with a detailed exploration of the functional properties of as-synthesized nanoparticles. By varying the precursor ratio between ammonia and tantalum ethanolate, five tantalum-based nanomaterials (TaNOC) are prepared with crystalline phases of Ta₂O₅, Ta₄N₅, Ta₃N₅, and TaN in tunable ratios. Electrochemical studies in neutral and alkaline conditions demonstrate that Ta₄N₅ is the active component for both H₂O₂ oxidation and reduction. Kinetic isotope effect studies show that protons are involved at or before the rate-determining step. Long-term stability studies indicate that Ta₃N₅ grants surfactant-free TaNOC-enhanced longevity during electrocatalytic operations. Taken together, bifunctional TaNOC can act as active and robust electrocatalysts for H₂O₂ reduction and oxidation. Laser pyrolysis is envisioned to produce refractory metal nanomaterials with boosted corrosion resistance for energy catalysis.<br></p>