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Aqueous Al-ion batteries are attractive post-lithium battery technologies. Here Al-Cu alloy lamellar heterostructures with periodic galvanic couplings are reported as efficient anode active material to produce high-energy aqueous Al-ion batteries.

Electrochemical water splitting is an attractive energy conversion technology, but it usually suffers from low efficiency. Here, the authors report intermetallic Co3Mo integrated on porous Cu as highly efficient electrocatalysts for alkaline HER/OER due to in-situ hydroxylation and electro-oxidation.

Designing highly active and robust platinum-free electrocatalysts for hydrogen evolution reaction is vital for large-scale and efficient production of hydrogen through electrochemical water splitting. Here, we report nonprecious intermetallic Cu5Zr clusters that are in situ anchored on hierarchical nanoporous copper (NP Cu/Cu5Zr) for efficient hydrogen evolution in alkaline medium. By virtue of hydroxygenated zirconium atoms activating their nearby Cu-Cu bridge sites with appropriate hydrogen-binding energy, the Cu5Zr clusters have a high electrocatalytic activity toward the hydrogen evolution reaction. Associated with unique architecture featured with steady and bicontinuous nanoporous copper skeleton that facilitates electron transfer and electrolyte accessibility, the self-supported monolithic NP Cu/Cu5Zr electrodes boost violent hydrogen gas release, realizing ultrahigh current density of 500 mA cm-2 at a low potential of -280 mV versus reversible hydrogen electrode, with exceptional stability in 1 M KOH solution. The electrochemical properties outperform those of state-of-the-art nonprecious metal electrocatalysts and make them promising candidates as electrodes in water splitting devices.

The hydrogen evolution reaction (HER) is a crucial step in alkaline water electrolysis, but suffers from sluggish reaction kinetics, which calls for the development of active and robust catalysts for the highly efficient production of high-purity hydrogen. Here, we report hierarchical nanoporous (NP) transition-metal (TM = Fe, Co)-doped Pt3Al intermetallic compounds, which are composed of surface alloys of Pt and TMs with in situ self-grown TM hydroxides in an alkaline environment, NP (Pt1-xTMx)3Al/Pt-TM(OH), as highly efficient bifunctional catalysts for the HER. By virtue of the constituent Co(OH)2 having moderate hydroxyl adsorption to accelerate water dissociation and the Pt atoms facilitating the adsorption/desorption of reactive hydrogen intermediates, the NP (Pt1-xCox)3Al/Pt-Co(OH)2 exhibits superior HER activity in 0.1 M KOH, with a low Tafel slope of 48 mV dec-1 and an overpotential of ~43 mV at 10 mA cm-2, as well as exceptional durability due to its unique nanoporous structure with stable intermetallic bonds. These electrocatalytic properties outperform state-of-the-art Pt-based catalysts, suggesting that multi-site design is suitable for producing highly efficient catalysts towards the HER in alkaline environments. [ABSTRACT FROM AUTHOR]