Reconstruction Induced Dynamic Incorporation of Zn Into Cobalt Hydroxide via Synergistic Structural Evolution for Efficient Hydrogen Evolution Reaction

Why It Matters

The approach delivers a low‑cost, corrosion‑resistant HER catalyst suitable for seawater electrolysis, a key hurdle for large‑scale green hydrogen production.

Key Takeaways

• ZnO dissolution drives Zn incorporation into Co(OH)2.
• Zn-doped Co(OH)2 achieves 40 mV overpotential at 10 mA cm⁻².
• Performance retained 65 mV in simulated seawater.
• Electrolyzer runs >650 h water, >1000 h seawater.
• DFT shows Zn mitigates Cl⁻ corrosion.

Pulse Analysis

Hydrogen evolution reaction (HER) catalysts based on earth‑abundant transition metals have attracted intense interest as alternatives to precious‑metal electrodes. Cobalt molybdate (CoMoO4) offers a promising scaffold, yet its intrinsic activity is limited by insufficient active sites and sluggish kinetics after surface reconstruction. Researchers have therefore focused on engineering the catalyst’s interface to promote favorable electronic structures and expose more reactive facets, a strategy that can unlock higher current densities at lower overpotentials.

In the newly reported ZnO@CoMoO4 architecture, ZnO nanorods are grown as a core‑shell overlayer on CoMoO4 particles. During electrolysis, ZnO continuously dissolves, supplying Zn²⁺ ions that are incorporated into the in‑situ formed Co(OH)2 matrix. This dynamic doping creates Zn‑doped Co(OH)2 with enhanced OH⁻ adsorption and modified electronic states, driving the HER overpotential down to 40 mV at 10 mA cm⁻². Even in a simulated seawater electrolyte, the catalyst maintains a low 65 mV overpotential, demonstrating that the Zn‑induced structural evolution mitigates the typical performance loss caused by chloride ions.

Beyond activity, durability is a decisive factor for commercial electrolyzers. The ZnO@CoMoO4 electrode sustains stable operation for more than 650 hours in pure water and exceeds 1,000 hours in seawater, outlasting many benchmark systems. Density‑functional theory calculations reveal that Zn dopants lower the hydrogen adsorption free energy and shield the active sites from Cl⁻ attack, explaining the observed corrosion resistance. By coupling dynamic material reconstruction with synergistic elemental incorporation, this work offers a scalable pathway to robust, low‑cost HER catalysts that can accelerate the deployment of seawater‑based hydrogen production at industrial scales.