The oxygen evolution reaction (OER) has been explored extensively for reliable hydrogen supply to boost the energy conversion efficiency. The superior OER performance of newly developed non‐noble metal electrocatalysts has concealed the identification of the real active species of the catalysts. Now, the critical active phase in nickel‐based materials (represented by NiNPS) was directly identified by observing the dynamic surface reconstruction during the harsh OER process via combining in situ Raman tracking and ex situ microscopy and spectroscopy analyses. The irreversible phase transformation from NiNPS to α‐Ni(OH)2 and reversible phase transition between α‐Ni(OH)2 and γ‐NiOOH prior to OER demonstrate γ‐NiOOH as the key active species for OER. The hybrid catalyst exhibits 48‐fold enhanced catalytic current at 300 mV and remarkably reduced Tafel slope to 46 mV dec−1, indicating the greatly accelerated catalytic kinetics after surface evolution.

Hydrogen storage is of great interest as environmentally clean and efficient fuels are required for future energy applications.[1] Several pioneering strategies have been developed and significant performances have been achieved for hydrogen storage, including chemisorption of dihydrogen in the form of light metal hydrides, [2] metal nitrides and imides, [3] physisorption of dihydrogen onto carbon, [4] clathrate hydrates, [5] and porous network materials such as carbon nanotubes (CNTs), [6] zeolites, [7] and metal-organic framework (MOF) materials.[8] However, hydrogen storage in these systems requires either high pressure or very low temperature, or both, thus severely limiting the applicability for mobile applications, which require working conditions of 1-20 bar and ambient temperature. The synthesis of functional materials with high hydrogen uptake and delivery under safe and ambient conditions remains a key challenge for establishing hydrogen economy.It has been reported that atomically dispersed alkalimetal ions (e.g., Li+ and Na +

High-performance electrocatalysts are desired for electrochemical energy conversion, especially in the field of water splitting. Here, a new member of phosphate electrocatalysts, nickel metaphosphate (Ni P O ) nanocrystals, is reported, exhibiting low overpotential of 270 mV to generate the current density of 10 mA cm and a superior catalytic durability of 100 h. It is worth noting that Ni P O electrocatalyst has remarkable oxygen evolution performance operating in basic media. Further experimental and theoretical analyses demonstrate that N dopant boosts the catalytic performance of Ni P O due to optimizing the surface electronic structure for better charge transfer and decreasing the adsorption energy for the oxygenic intermediates.

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Through systematic molecular dynamics simulations we theoretically investigate the potential applications of hexagonal boron nitride (h-BN) for seawater desalination. Our results indicate that the rationally designed h-BN membranes have great permeability, selectivity, and controllability for water desalination. The size and chemistry of the pores are shown to play an important role in regulating the water flux and salt rejection. Pores with only nitrogen atoms on the edges have higher fluxes than the boron-lined pores. In particular, two-dimensional h-BN with medium-sized N4 pores show 100% salt rejection with outstanding water permeability, which is several orders of magnitude higher than that of conventional reverse osmosis membranes. Furthermore, we study the mechanical strain effect on the desalination performance of monolayer h-BN with relatively small N3 pores, suggesting that water flux and salt rejection can be precisely tuned by tensile strain. The findings in the present work unambiguously propose that porous boron nitride nanosheets are quite promising as new functional membranes for water desalination.

The unprecedented applications of two-dimensional (2D) atomic sheets in spintronics are formidably hindered by the lack of ordered spin structures. Here we present first-principles calculations demonstrating that the recently synthesized dimethylmethylene-bridged triphenylamine (DTPA) porous sheet is a ferromagnetic half-metal and that the size of the band gap in the semiconducting channel is roughly 1 eV, which makes the DTPA sheet an ideal candidate for a spin-selective conductor. In addition, the robust half-metallicity of the 2D DTPA sheet under external strain increases the possibility of applications in nanoelectric devices. In view of the most recent experimental progress on controlled synthesis, organic porous sheets pave a practical way to achieve new spintronics.

We carry out a combined theoretical and experimental investigation on the population distributions in the ground and excited states of tunnel-ionized nitrogen molecules at various driver wavelengths in the near- and midinfrared range. Our results reveal that efficient couplings (i.e., population exchanges) between the ground N_{2}^{+}(X^{2}Σ_{g}^{+}) state and the excited N_{2}^{+}(A^{2}Π_{u}) and N_{2}^{+}(B^{2}Σ_{u}^{+}) states occur in strong laser fields. The couplings result in a population inversion between the N_{2}^{+}(X^{2}Σ_{g}^{+}) and N_{2}^{+}(B^{2}Σ_{u}^{+}) states at wavelengths near 800 nm, which is verified by our experimental observation of the amplification of a seed at ∼391  nm. The result provides insight into the mechanism of free-space nitrogen ion lasers generated in remote air with strong femtosecond laser pulses.