Concomitant Rich Cobalt and Nickel Dual Active Sites in Janus Tubular Co3O4/NiCu Heterostructure for Ambient Hydrazine-Assisted Hydrogen Production Up to 3.0 A cm-2

Hydrazine oxidation assisted energy-efficiency hydrogen production offers a promising rationale for sustainable clean energy conversion technologies, yet developing unique-structured electrocatalysts towards ampere-scale hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER) is still a grand challenge. Herein, we constructed highly arranged Janus tubular Co3O4/NiCu heterostructure via a rationally designed voltametric-assisted alloying-selective dealloying process (denoted as Co3O4/NiCu/NF) for the massive exposure of cobalt and nickel dual active sites with distinct heterostructures. Serving as bifunctional catalyst, it endows the Co3O4/NiCu/NF electrode extraordinary industrial-scale current densities of 1.0 and 3.0 A cm-2 at ultralow overpotentials of 265 and 433 mV for HzOR and 171 and 263 mV for HER, respectively. In the assembled electrolyzer towards overall hydrazine splitting (OHzS) cell, the Co3O4/NiCu/NF couple delivers exceptionally low voltages of 0.955 and 1.65 V at 1.0 and 2.0 A cm-2, respectively, maintaining stable operation with minimal degradation. Mechanism investigations reveal that the Co sites at Co3O4/NiCu heterointerface enact the active center for HER, whilst Ni sites for HzOR, for elevating the hydrogen adsorption and hydrazine dehydrogenation kinetics. The superior catalytic activity and robust electrocatalysis ensure its great potential in industrial application.