Highly dispersed ZnO/g-C₃N₄ composites with different doping ratios of g-C₃N₄ were prepared by a hydrothermal method. The preparation method is simple and the energy consumption is low. The composite samples were used to degradate the methyl orange solution. They all showed excellent photocatalytic activity and cycling stability. The optimal loading content of g-C₃N₄ was investigated, and the mechanism of enhanced photocatalytic activity was studied in detail. This study provides a promising photocatalytic material for the removal of organic pollutants.

LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) became a research hot point because of its low cost, environmental friendliness, and excellent electrochemical performance. However, Li⁺/Ni²⁺ intermixing is an essential factor affecting its applicability. Doping could be an important method to improve the electrochemical performance of NCM811-based cathode materials. In this work, La and Al co-doped NCM811 was prepared by a solid-state method. Results from X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) and electrochemical performance were discussed in depth. These showed that when La and Al doping concentrations were 1 and 0.5%, the samples showed the best performance. The as-improved performances were mainly attributed to the reduced Li⁺/Ni²⁺ intermixing, suppressed phase transition, and decreased potential polarization and impedance.

Co³⁺ doping in BiFeO₃ is expected to be an effective method for improving its magnetic properties. In this work, pristine BiFeO₃ (BFO) and doped BiFe_1-xCo_xO₃ (BFC_xO, x = 0.01, 0.03, 0.05, 0.07 and 0.10) composite thin films were successfully synthesized by a sol–gel technique. XRD and Raman spectra indicate that the Co³⁺ ions are substituted for the Fe³⁺ ion sites in the BFO rhombohedral lattice. Raman vibration of oxygen octahedron is obviously weakened due to the lattice distortion induced by the size mismatch between two B-site cations (Fe³⁺ and Co³⁺ ions), which has an impact on the magnetic properties of BFC_xO. SEM images reveal a denser agglomeration in Co-doped samples. TEM results indicate that the average size of grains is reduced due to the Co³⁺ substitution. XPS measurements illustrate that the replacement of Fe³⁺ with Co³⁺ effectively suppresses the generation of oxygen defects and increases the concentration of Fe³⁺ ions at the B-site of perovskite lattice. Vibrating sample magnetometer (VSM) measurements show that the remanent magnetization (Mr) of BFC_0.07O (3.6 emu/cm³) and the saturation magnetization (Ms) of BFC_0.10O (48.84 emu/cm³) thin film both increase by approximately two times at room temperature, compared with that of the pure BFO counterpart.

Dumbbell Ag₂CO₃–ZnO heterojunctions were synthesized for the first time via a simple in situ precipitation method. The as-prepared Ag₂CO₃–ZnO heterojunction showed high photocatalytic activity in the decomposition of methyl orange aqueous solution under simulated solar irradiation. The high improvement of photocatalytic activity compared to that of pure ZnO can be attributed to the formation of the Ag₂CO₃–ZnO heterojunction. Furthermore, the mechanism of photocatalytic activity was investigated in detail. The free radical trapping experiments indicated that the superoxide radical (·O₂^–) was an important active species in the photocatalytic process. This paper provides a new prospect for the preparation of photocatalysts with high catalytic performance in the degradation of dye wastewater.