CuPt nano-alloy as bifunctional electrocatalyst for N2H4 oxidation-assisted H2 generation and multifunctional sensor materials

Abstract

This work combined lattice strain effect and surfactant-free interface of CuPt nanoalloy to achieve the low-potential catalytic H₂ Evolution Reaction (HER) and Hydrazine Oxidation Reaction (HzOR). Compared to the electro-catalysis of oxygen evolution reaction, the CuPt nano-alloy exhibited a lower potential in the electro-catalysis of HzOR. The voltage required for N₂H₄ oxidation-assisted H₂ generation by surfactant-free Cu₈₃Pt₁₇ nano-alloy was 0.28 V (at 10 mA/cm²), which was only 14.97 % of that needed for H₂O splitting (1.87 V at 10 mA/cm²). Moreover, the ligand-free surface maximized the interfacial contact area of CuPt nanoalloy with reactants, thereby enhancing both its stability and electrocatalytic activity in both the cathode and anode reactions. As compared with the CuPt nano-alloy synthesized by using a surfactant (Un-CuPt), the surfactant-free Cu₈₃Pt₁₇ nano-alloy in this work could achieve a 39.1 % reduction in the working voltage for N₂H₄ splitting. When the output current density reaches 100 mA/cm², the corresponding working potential for HzOR was 435.31 mV vs RHE. After a 72-h for HzOR, the anode potential (at 10 mA/cm²) for the surfactant-free Cu₈₃Pt₁₇ nano-alloy increased by only 3.97 % (158.8 mV–165.1 mV), indicating its promising stability. As a multifunctional electrocatalyst, the CuPt nano-alloy demonstrated a promising performance in the construction of H₂O₂ and NaNO₂ sensors. This work successfully introduced a bifunctional electrocatalyst for N₂H₄ oxidation-assisted H₂ generation, addressing the inferior catalytic activity of commercial Pt/C in HzOR and its inadequate stability. Considering the relatively low cost of Cu, the obtianed results would pave a promising research avenue for designing highly efficient electrocatalysts for H₂ generation or constructing sensors.