Oxygen electrocatalysis is of great significance for various energy conversion and storage-related applications. Herein, by using in situ polymerization of dopamine on specially designed metal–organic framework (MOF) nanocubes and subsequent annealing treatment, well-defined Co/N-doped carbon hollow nanocubes with high electrocatalytic activity and stability toward the oxygen evolution reaction are obtained. To attain a current density of 10 mA cm⁻², the overpotential required for the Co/N-doped carbon hollow nanocubes is only 285 mV, which is comparable to that of commercial RuO₂ (270 mV) and lower than those of most MOF-derived ones and other carbon supported Co-based electrocatalysts. Surprisingly, we find that when the Co nanoparticles are leached using simple acid wash, the as-synthesized N-doped carbon hollow nanocubes could act as an efficient electrocatalyst for the oxygen reduction reaction instead. The strategy presented here for controlled design and synthesis of MOF-derived hollow (metal)/N-doped carbon frameworks would offer new prospects for developing efficient oxygen electrocatalysts for electrochemical energy devices.

Three-dimensionally ordered macroporous (3DOM) NiCe catalysts with different Ni/Ce molar ratio were fabricated using the colloidal crystal templating method. The physic-chemical properties of the samples were characterized by various techniques, including N₂ adsorption–desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, and H₂-temperature-programmed reduction (TPR) characterizations. The results revealed that the 3DOM NiCe samples preserved the three-dimensionally ordered macroporous channels with interlinked micro- or mesoporous structure and highly dispersed nickel oxide species in the framework upon different amount of nickel incorporation. In the evaluation of the oxidative dehydrogenation (ODH) of propane, the 3DOM NiCe catalysts exhibited higher selectivity and yield to propene than the amorphous NiCe catalyst. An optimum yield of propene of 11.9% with the 30.3% propane conversion at 375 °C was obtained over the 3DOM 2NiCe catalyst. Combining XRD, TPR, and Raman analysis, it could be found that the nickel incorporation in CeO₂ lattice produced a high concentration of oxygen vacancies that were the active sites for the oxidative dehydrogenation of propane. Besides this, the 3DOM structure promoted the rapid diffusion of the reactants and products—favorable for the generation of propene in the ODH of propane.

Radioactive nuclides such as cesium, ruthenium, and iodine are difficult to remove in radioactive wastewater, which could be removed by coprecipitation of special chemical precipitants. In this study, dynamic Cu/Ag-mordenite (Cu/Ag-MOR) material was synthesized to be treated as the precipitant to selectively adsorb the iodine ion (I⁻) through controlled chemisorption combined with physical adsorption. XRD, XPS, and FTIR characterization demonstrated the successful modification of the MOR carrier surface by Cu/Ag particles and the high selectivity of the active component Cu (I) on the dynamic Cu/Ag-MOR material. SEM, TEM, and BET methods were used to characterize the Cu/Ag-MOR material, demonstrating these results: the MOR carried a stable porous structure, which allowed the silver to be well dispersed on its surface. The silver improved the copper distribution by being well-coated by the copper species. Furthermore, the analysis of the factors influencing the chemical plating of copper showed that the pH, the concentration of EDTA-2Na and the temperature all influenced the deposition rate of Cu₂O. The activation energy for Cu₂O deposition in dynamic Cu/Ag-MOR was 20.31 kJ/mol. The highest removal of I⁻ in the presence of dynamic Cu/Ag-MOR could reach 99.1% in the adsorption tests. The adsorption kinetics was under a proposed second-order model, with chemisorption being the controlling step of the reaction. The adsorption/desorption experiments demonstrated the reusability of the nano-sorbent. It was also demonstrated that dynamic Cu/Ag-MOR materials showed good applicability in complex situations where multiple pollutants co-exist.

This paper describes the application of P-Mo-V-Nb/SiO₂ catalysts for the selective oxidation of ethyl lactate (EL) to ethyl pyruvate (EP). The P-Mo-V-Nb/SiO₂ catalysts exhibit superior performance for EP selectivity than the corresponding samples of binary V-Nb/SiO₂ ternary P-Mo-V/SiO₂ and P-Mo-Nb/SiO₂ catalysts at same temperatures. The origin of high EP selectivity of the P-Mo-V-Nb/SiO₂ catalysts is explored and attributed to the synergistic effect of P, Mo, V, and Nb mixed oxides presented on the surface of the catalyst. The highly dispersive sites separated active species under the action of phosphorus, suppressing over oxidation and improving the selectivity. The existence of MoO₃ to provide higher oxidation for catalyst. The redox cycle of V and Nb oxides could be completed through electron transfer between lattice oxygen and metal cations. Moreover, the weak acidity of catalyst surface is favorable to avoid the decarboxylation reaction to target a high selectivity of EP. Therefore, the P-Mo-V-Nb/SiO₂ catalyst obtained the maximum yield of 91.8% with a selectivity of 93.8% and a conversion of 99.0% simultaneously at 280 °C.

This paper describes the application of Fe-MCM-48 (Mobil Composition of Matter No.48) and cellulase-MCM-48 catalysts for the depolymerization of chitosan. The results show that H₂O₂ is a good oxidant for the depolymerization of chitosan in the presence of Fe-MCM-48. The average polymerization degree of the product decreased to 6.1, and decreased to 29.2 when cellulase-MCM-48 was used as a catalyst, because the effect of the enzyme was affected by the molecular structure of chitosan. When both materials were used for depolymerization, the average degree of polymerization sharply decreased to 3.8. The results show that the two degradation methods can promote each other to obtain oligosaccharides with a lower degree of polymerization. This provides a new method for the controllable degradation of chitosan and lays a good foundation for the industrial production of chitosan oligosaccharides with a low degree of polymerization.