Flower-like molybdenum disulfide decorated ZIF-8-derived nitrogen-doped dodecahedral carbon for electro-catalytic degradation of phenol.

In this work, flower-like molybdenum disulfide was constructed on the surface of ZIF-8-derived nitrogen-doped dodecahedral carbon (ZNC) for the electrocatalytic degradation of phenol. The flower-like nanostructure of MoS2@ZNC contributed to the exposure of more edge-active sites of MoS2. At the same time, Mo4+ and Mo6+ co-existed in MoS2@ZNC, which promoted the generation of H2O2 and •OH, and improved the catalytic activity of composite materials. In addition, electrochemical performance analysis showed that MoS2 loaded on the surface of ZNC significantly improved the redox capacity of the material, and the composite ratio of MoS2 and ZNC affected the structure and properties of MoS2@ZNC composites. Moreover, the electrochemical performance of prepared MoS2@ZNC was evaluated by the generation of hydroxyl (•OH) and the degradation efficiency of phenol. The results showed that MoS2@ZNC-2 had an excellent phenol degradation efficiency (98.8%) and COD removal efficiency (86.8%) within 120 min. Furthermore, MoS2@ZNC cathode still maintained good performance after being experimented with 20 times, indicated the excellent stability of MoS2@ZNC.

Effective electro-Fenton-like process for phenol degradation on cerium oxide hollow spheres encapsulated in porous carbon cathode derived from skimmed cotton.

The uniform size cerium dioxide hollow spheres which were prepared by the SiO2 hard template method were loaded on microporous porous carbon obtained by carbonization derived from skimmed cotton (CSC) for electro-Fenton-like degradation of phenol. The microstructures of CSC/CeO2 composite materials were characterized utilizing XRD, BET, XPS, SEM, and TEM. The electrochemical performance of the CSC/CeO2 cathodes was studied through cyclic voltammetry and electrochemical impedance spectroscopy. The prepared CSC has a hollow tubular structure, and cerium dioxide is evenly loaded on the surface of the CSC in the form of uniform-sized hollow spheres. The CSC/CeO2 materials have a great specific surface area (287.73 m2 g-1) and a uniform poresize. The electrochemical performance analysis demonstrated that the redox ability of the material greatly was improved by loading CeO2 on the porous carbon surface of the skimmed cotton. The load ratio of cerium dioxide hollow spheres affects the structure and properties of CSC/CeO2 materials. Ce3+ and Ce4+ were co-existed in CSC/CeO2, which promoted the generation of H2O2 and .OH, and improved the catalytic activity of composite materials. The degradation efficiency of phenol reached 97.6% in 120 min, and the CSC/CeO2 cathode manifested excellent stability after being experimented 20 times. CSC/CeO2 composite material has great practical value in the treatment of phenolic wastewater and has promise for further application.

Nickel and cobalt metal-organic-frameworks-derived hollow microspheres porous carbon assembled from nanorods and nanospheres for outstanding supercapacitors.

The development of efficient electrode materials is essential to promote the performance of energy storage equipment. Nowadays, metal organic frameworks (MOFs) have been widely regarded as active materials for supercapacitors mainly thanks to their adjustable structure and outstanding porosity. Here, highly optimized Nickel and Cobalt MOF-derived N-doped porous carbon (Ni/Co-MOF-NPC) are considered the best choice for electrode materials due to their unique structural properties and excellent electrochemical performance. Pure cobalt oxide rarely reaches a specific capacitance of 104.3 F g-1 when the current density is 1 A g-1, but the optimized Ni/Co-MOF-NPC-2:1 offers an ultra-high specific capacitance of 1214 F g-1, which is much higher than that of pure cobalt oxide in a three-electrode test system. When the current density is 10 A g-1, after 6000 cycles, the capacitance can still maintain 98.8% of the initial capacitance. Asymmetric supercapacitors were assembled using the prepared Ni/Co-MOF-NPC-2:1 as the positive electrode material, corrugated paper activated carbon (CPAC) as the negative electrode material, the prepared Ni/Co-MOF-NPC-2:1//CPAC exhibits an outstanding energy density of 55.4 Wh kg-1 at 758.5 W kg-1, and has a significant cycle stability of 75.2% retention after 20,000 cycles. This excellent MOF synthesis strategy reduced the gap between the experimental synthesis and practical application of MOF in fast energy storage.

Three-Dimensional Hierarchical Porous Carbon Cathode Derived from Waste Tea Leaves for the Electrocatalytic Degradation of Phenol.

Tea leaves have been explored as an economically viable and environmentally friendly source of biomass carbon. Tea leaf porous carbon (TPC) with a three-dimensional (3D) structure was prepared by a potassium hydroxide pretreatment and high-temperature calcination method, and the preparation process was simple and self-templating. The prepared TPC has a large specific surface area (1620.05 m2 g-1), three-dimensional multilayer pore structure, uniform pore size, and high oxygen content (15.51%). Both the calcination temperature and the activation level have an effect on the structure and performance of the TPC. The TPC electrode can generate a large amount of hydrogen peroxide in the initial stage of the degradation process, thereby increasing the amount of hydroxyl radicals generated and removing organic pollutants. Therefore, phenol was used to test the degradation effects and evaluate the degradation performance of TPC. Under suitable degradation conditions, TPC-800-2 showed a 95.41% degradation rate after 120 min of degradation, which is superior to that of other calcination temperatures and activation levels. The removal efficiency of chemical oxygen demand after 180 min was 90.0% and showed good stability after being used 20 times. Our work illustrates that a simple, high-performance self-templating synthetic strategy for producing novel 3D-TPC from biomass sources can play a significant role in the actual wastewater treatment of other biomass materials.