The high intermediate (H*, OH*) energy barriers and slow mass/charge transfer increase the overpotential of alkaline water electrolysis at large‐current‐density. Engineering the electronic structure with the morphology of the catalyst to reduce energy barriers and improve mass/charge transportation is effective but remains challenging. Herein, a Ce‐doped CoP nanosheet is hybrid with Ni3P@NF (Ni foam) support to enhance mass/charge transfer, tune energy barriers, and improve water‐splitting kinetics through a synergistic activation. The engineered Ce0.2‐CoP/Ni3P@NF cathode exhibits an ultralow overpotential (η500, η1000) of −185, and −225 mV at −500 and −1000 mA cm−2 in 1.0 m KOH, along with an excellent pH‐universality. Impressively, an electrolyzer using the Ce0.2‐CoP/Ni3P@NF cathode can afford 500 mA cm−2 at a cell voltage of only 1.775 V and maintain stable electrolysis for 200 h in 25 wt% KOH (50 °C). Characterization and density functional theory calculation further reveal the Ce‐doping and CoP/Ni3P hybrid interaction synergistically downshift d‐band centers (εd = −2.0 eV) of Ce0.2‐CoP/Ni3P to the Fermi level, thereby activate local electronic structure for accelerating H2O dissociation and optimizing Gibbs free energy of hydrogen adsorption (∆GH*).

The spent neodymium–iron–boron (NdFeB) magnet is a highly valuable secondary resource of rare earth elements (REEs). Hydrometallurgical processes are widely used in recovering REEs from spent NdFeB magnets, but they will consume large amounts of organic chemicals, leading to severe environmental pollution. This work developed an alternative green route to selectively recover REEs from spent NdFeB permanent magnets using a purely inorganic zinc salt. The Hammett acidity measurement showed that concentrated ZnCl2 solutions could be regarded as a strong Brønsted acid. Concentrated ZnCl2 solutions achieved a high separation factor (>1 × 105) between neodymium and iron through simple dissolution of their corresponding oxide mixture. In the simulated recovery process of spent NdFeB magnets, the Nd2O3 product was successfully recovered with a purity close to 100% after selective leaching by ZnCl2 solution, sulfate double-salt precipitation, and oxalic acid precipitation. The separation performance of the ZnCl2 solution for Nd2O3 and Fe2O3 remained almost unchanged after four cycles. The energy consumption and chemical inputs of this process are about 1/10 and half of the traditional hydrometallurgy process separately. This work provides a promising approach for the green recovery of secondary REE resources.

Hydrogen, with clean and high gravimetric energy density features, has been considered as an ideal energy carrier. Electrochemical water splitting that can convert the intermittent electricity generated from wind and...