Complex nano-architectures with ordered two-dimensional (2D) building blocks are a class of promising electrocatalysts for different electrochemical technologies. In this work, a novel template-engaged strategy followed by sequential etching and phosphorization treatments is demonstrated to fabricate open and hierarchical Ni–Co–P hollow nanobricks (HNBs) via the assembly of oriented 2D nanosheets. Benefiting from the unique nano-architectures with large electrolyte-accessible surface and abundant mass diffusion pathways, the as-prepared Ni–Co–P HNBs exhibit high electrocatalytic activity, which affords the current density of 10 mA cm⁻² at low overpotentials of 270 mV and 107 mV for oxygen and hydrogen evolution reactions respectively, and excellent stability in an alkaline medium. Remarkably, when used as both the anode and cathode, a low cell voltage of 1.62 V is required to reach the current density of 10 mA cm⁻², making the Ni–Co–P HNBs an efficient bifunctional electrocatalyst for overall water splitting.

Novel hierarchical nanostructures composed of carbon coated α-Fe₂O₃ hollow nanohorns on carbon nanotube (CNT) backbones have been constructed by direct growth and thermal transformation of β-FeOOH nanospindles on CNTs, followed by carbon nanocoating. When evaluated as a potential anode material for lithium-ion batteries, such hierarchical structures exhibit superior lithium storage capabilities by virtue of their advantageous structural features.

Oxygen evolution reaction (OER) is critical to renewable energy conversion technologies, but the structure-activity relationships and underlying catalytic mechanisms in catalysts are not fully understood. We herein demonstrate a strategy to promote OER with simultaneously achieved lattice oxygen activation and enhanced local electric field by dual doping of cations and anions. Rough arrays of Fe and F co-doped CoO nanoneedles are constructed, and a low overpotential of 277 mV at 500 mA cm⁻² is achieved. The dually doped Fe and F could cooperatively tailor the electronic properties of CoO, leading to improved metal-oxygen covalency and stimulated lattice oxygen activation. Particularly, Fe doping induces a synergetic effect of tip enhancement and proximity effect, which effectively concentrates OH⁻ ions, optimizes reaction energy barrier and promotes O₂ desorption. This work demonstrates a conceptual strategy to couple lattice oxygen and local electric field for effective electrocatalytic water oxidation.