Various platinum-free electrocatalysts have been explored for hydrogen evolution reaction in acidic solutions. However, in economical water-alkali electrolysers, sluggish water dissociation kinetics (Volmer step) on platinum-free electrocatalysts results in poor hydrogen-production activities. Here we report a MoNi₄ electrocatalyst supported by MoO₂ cuboids on nickel foam (MoNi₄/MoO₂@Ni), which is constructed by controlling the outward diffusion of nickel atoms on annealing precursor NiMoO₄ cuboids on nickel foam. Experimental and theoretical results confirm that a rapid Tafel-step-decided hydrogen evolution proceeds on MoNi₄ electrocatalyst. As a result, the MoNi₄ electrocatalyst exhibits zero onset overpotential, an overpotential of 15 mV at 10 mA cm⁻² and a low Tafel slope of 30 mV per decade in 1 M potassium hydroxide electrolyte, which are comparable to the results for platinum and superior to those for state-of-the-art platinum-free electrocatalysts. Benefiting from its scalable preparation and stability, the MoNi₄ electrocatalyst is promising for practical water-alkali electrolysers.

A 3D ternary hybrid containing Co_0.85Se nanosheet-array and NiFe-LDH grown on electrochemically exfoliated graphene was synthesized for highly-efficient overall water-splitting.’

Two-dimensional nanofluidic channels are emerging candidates for capturing osmotic energy from salinity gradients. However, present two-dimensional nanofluidic architectures are generally constructed by simple stacking of pristine nanosheets with insufficient charge densities, and exhibit low-efficiency transport dynamics, consequently resulting in undesirable power densities (<1 W m⁻²). Here we demonstrate MXene/Kevlar nanofiber composite membranes as high-performance nanofluidic osmotic power generators. By mixing river water and sea water, the power density can achieve a value of approximately 4.1 W m⁻², outperforming the state-of-art membranes to the best of our knowledge. Experiments and theoretical calculations reveal that the correlation between surface charge of MXene and space charge brought by nanofibers plays a key role in modulating ion diffusion and can synergistically contribute to such a considerable energy conversion performance. This work highlights the promise in the coupling of surface charge and space charge in nanoconfinement for energy conversion driven by chemical potential gradients.

Replacement of precious platinum with efficient and low-cost catalysts for electrocatalytic hydrogen evolution at low overpotentials holds tremendous promise for clean energy devices. Here we report a novel type of robust cobalt–nitrogen/carbon catalyst for the hydrogen evolution reaction (HER) that is prepared by the pyrolysis of cobalt–N₄ macrocycles or cobalt/o-phenylenediamine composites and using silica colloids as a hard template. We identify the well-dispersed molecular CoN_x sites on the carbon support as the active sites responsible for the HER. The CoN_x/C catalyst exhibits extremely high turnover frequencies per cobalt site in acids, for example, 0.39 and 6.5 s⁻¹ at an overpotential of 100 and 200 mV, respectively, which are higher than those reported for other scalable non-precious metal HER catalysts. Our results suggest the great promise of developing new families of non-precious metal HER catalysts based on the controlled conversion of homogeneous metal complexes into solid-state carbon catalysts via economically scalable protocols.