Dual-Functional Heterogeneous Rh–Sb Alloy Nanomaterials Coupling Electrochemical Hydrazine Oxidation and Hydrogen Evolution

The
overall hydrazine splitting (OHzS, N2H4 →
N2 + 2H2) reaction, which is integrated
by electrocatalytic hydrazine oxidation reaction (HzOR) and hydrogen
evolution reaction (HER), provides an energy-efficient alternative
to conventional overall water splitting (OWS) for sustainable hydrogen
production. Herein, we present the controlled synthesis of Rh1Sb1@Rh–Sb nanoflowers (NFs) that comprise
intermetallic Rh1Sb1 nanodendrite cores and
ultrathin Rh–Sb random alloy nanosheet shells. The alloying
of Sb enhances both HzOR and HER performances of Rh nanocatalysts
through modulation of growth mechanisms, morphological evolution,
and surface electronic configurations. Remarkably, a symmetrical OHzS
electrolyzer employing Rh1Sb1@Rh–Sb NFs
as bifunctional catalysts for both electrodes achieves the current
densities of 100 and 500 mA cm–2 at cell voltages
of merely 0.216 and 0.700 V (without iR compensation),
respectively, corresponding to 88.1% and 71.9% reductions in electricity
consumption compared to alkaline OWS systems. Furthermore, a rechargeable
zinc–hydrazine (Zn–Hz) battery using Rh1Sb1@Rh–Sb NFs as the positive electrode exhibits high
energy efficiency, power density, and durability. The prototype device,
integrating a photovoltaic cell, a Zn–Hz battery, and an OHzS
cell, demonstrates the potential for efficient and simultaneous solar
energy storage, hydrazine pollutant remediation, and hydrogen generation,
offering a promising avenue for practical applications.