Recently, magnetic two-dimensional Cr₂TiC₂T_x MXenes with promising applications in spin electronics have been experimentally confirmed. However, the underlying magnetic mechanism needs to be further investigated. Along these lines, in this work, the magnetic properties of Cr₂TiC₂O_n/4F_2−n/4 and Cr₂TiC₂O_n/4 structures were simulated through first-principle calculations using the GGA+U approach. The values of 4.1 and 3.1 eV were calculated for the Hubbard U of Cr and Ti, respectively, by applying the linear response method. Interestingly, the Cr₂TiC₂O_n/4F_2−n/4-based configurations with low O content (n ≤ 4) exhibit antiferromagnetic behavior, while the majority of the respective configurations with high O content (n ≥ 5) are ferromagnetic. As far as the Cr₂TiC₂O_5/4F_3/4 structure (n = 5) is concerned, the value of about 2.64 μ_B was estimated for the magnetic moment of the Cr atom. On top of that, the Curie temperature lies within the range of 10~47 K. The extracted theoretical results are in good agreement with experimental outcomes of the Cr₂TiC₂O_1.3F_0.8-based structure. From the simulated results, it can be also argued that the magnetic moment of Cr atoms and the Neel temperature can be directly tuned by the active content of O atoms. The conductivity of both Cr₂TiC₂O_n/4F_2−n/4 and Cr₂TiC₂O_n/4 configurations can be regulated by the externally applied magnetic field, while the density of states around the Fermi level shifted significantly between ferromagnetic and antiferromagnetic arrangements. The acquired results provide important theoretical insights to tuning the magnetic properties of Cr₂TiC₂T_x-based structures through surface termination mechanisms, which are quite significant for their potential applications in spin electronics.

Noble metal-free electrocatalysts have received widespread attention in a hydrogen evolution reaction (HER) due to the importance of renewable energy development. Herein, a Co₂P/CoP heterojunction embedded on an N-doped carbon (Co₂P/CoP/NC) electrocatalyst was prepared via an in situ pyrolysis method. The as-prepared electrocatalyst exhibited efficient electrocatalytic activity for HER in an acidic solution. The Co₂P/CoP/NC catalyst displayed an overpotential of 184 mV at 10 mA cm⁻² and a low Tafel slope of 82 mV dec⁻¹, which could be attributed to the tight Co₂P/CoP heterojunction and the synergetic effect of Co₂P/CoP and N-doped carbon. In addition, the electrochemical active surface area of Co₂P/CoP/NC was 75.2 m² g⁻¹, which indicated that more active regions can be applied for the HER process. This report may pave a new way for the design of efficient and low-cost N-doped-carbon-supported 3d transition metal phosphide electrocatalysts.

The widespread industrialization of high-energy density commercial lithium-ion batteries has long been challenged by issues of safety and efficiency stemming from uncontrollable lithium dendritic growths. Here, an island-coated composite separator has been fabricated using a pre-swelling process with water-based dispersions to address the issue of dendrite growth. The pre-swelling of the polymer particle surface balances the contradiction between the high crystallinity and electrolyte compatibility showing high electrolyte wettability and electrolyte uptake ability. Furthermore, the point-to-point surface structure can balance the high interfacial adhesion of electrodes and anti-deformation ability well, which is beneficial for preventing ripple-shaped and pot-shaped deformation, smoothing the solid particle morphology of the electrode and achieving a steady interfacial structure for lithium diffusion in cells. This new strategy constructs a non-continuous novel structure, achieving greatly improved dendrite growth suppressing and cell interface stabilization. This paper has opened up a new method for the development of low cost, simple process and easy industry of the lithium-ion pouch cell with improved quality and efficiency.

Herein, we synthesized a surface reconstructed polymeric carbon nitride through LiOH post-thermal treatment. The catalysts were applied in photocatalytic H₂O₂production.