This study focuses on preparing composite hierarchical porous carbon nanofiber film that includes ZnO and MnO₂. Using electrospinning technology, hierarchical porous structure was introduced into the nanofibers, enhancing energy density through the synergistic effect of zinc oxide and manganese dioxide. The zinc-manganese dioxide co-modified hierarchical porous carbon nanofiber film (ZnMnO-HPC) exhibits outstanding electrochemical performance when used as supercapacitor electrode, with a specific capacity reaching 401.77 C/g at 0.5 A/g, and 201.29 C/g at high current density of 5 A/g. ZnMnO-HPC also exhibits remarkable energy density when assembled with activated carbon electrode into asymmetric capacitor, reaching 38.37 Wh/kg at a power density of 407 W/kg and 19.5 Wh/kg at a power density of 12,800 W/kg, indicating promising applications in the high-energy-density supercapacitor field.

Oxygen vacancies (OVs) have critical effects on the photoelectric characterizations and photocatalytic activity of nanoceria, but the contributions of surface OVs on the promoted photocatalytic properties are not clear yet. In this work, we synthesized ceria nanopolyhedron (P-CeO₂), ceria nanocube (C-CeO₂) and ceria nanorod (R-CeO₂), respectively, and annealed them at 600 °C in air, 30%, 60% or pure H₂. After annealing, the surface OVs concentration of ceria elevates with the rising of H₂ concentration. Photocatalytic activity of annealed ceria is promoted with the increasing of surface OVs, the methylene blue photodegradation ratio with pure hydrogen annealed of P-CeO₂, C-CeO₂ or R-CeO₂ is 93.82%, 85.15% and 90.09%, respectively. Band gap of annealed ceria expands first and then tends to narrow slightly with the rising of surface OVs, while the valence band (VB) and conductive band (CB) of annealed ceria changed slightly. Both of photoluminescence spectra and photocurrent results indicate that the separation efficiency of photoinduced electron-hole pairs is significantly enhanced with the increasing of the surface OVs concentration. The notable weakened recombination of photogenerated carrier is suggested to attribute a momentous contribution on the enhanced photocatalytic activity of ceria which contains surface OVs.

When alumina is produced by the Bayer process with high-sulfur bauxite, the sulfur would strongly corrode the 12Cr1MoV steel made heat exchanger. This study investigated the initial corrosion behavior of the 12Cr1MoV steel exposed to a thiosulfate-containing sodium aluminate (TCSA) solution under the evaporation conditions of alumina production. The obtained corrosion rate equation is V = 6.306·t·exp(−0.71). As corrosion progressed, with the corrosion product film growing, the corrosion current density declines slowly, and the corrosion resistance of the steel is increased. At 1–3 days, the corrosion product film consisted of FeO, Fe₂O₃, and FeOOH. S₂O₃²⁻ lead to corrosion in local areas of the steel and pits appeared. AlO₂⁻ is transformed into Al(OH)₃ and filled in the corrosion pits. At 4 and 5 days, Fe₃O₄ is generated in the outermost layer, and Al(OH)₃ is shed from the corrosion pits. The corrosion mechanism of 12Cr1MoV steel in a TCSA solution is proposed based on the experimental results.

This study aimed to investigate the effect of Mg treatment on the nucleation and ostwald growth of inclusions. Deoxidized experiments with Al (0.05%Al) and Al-Mg (0.05%Al + 0.03%Mg) were carried out at 1873 K, and the composition, number, and size of inclusions were studied as a function of holding time. Homogeneous nucleation theory and ostwald ripening were utilized to calculate the nucleation rate, the critical size of nuclei, and coarsening rate of inclusions. The results show that small inclusions were more easily found in the steels with Al-Mg complex deoxidation, and the number of inclusions with Al-Mg complex deoxidation is larger at an early stage of deoxidation. The critical size of nuclei increases in the order of MgAl₂O₄ (0.3–0.4 nm) < Al₂O₃ (0.4–0.6 nm), and the nucleation rate increases in the order of Al₂O₃ (1100 cm⁻³ s⁻¹) < MgAl₂O₄ (1200 cm⁻³s⁻¹), which is consistent with the experimental results. Moreover, the coarsening rate of MgAl₂O₄ inclusions was smaller than Al₂O₃ inclusions in both the value of k_d(cal.) from ostwald growth and the value of k_d(obs.) from inclusion size. The effect of Mg addition on coarsening of inclusion was analyzed and their mechanism was discussed based on ostwald ripening theory and Factsage calculation.