Nickel cobaltite composite electrodes were fabricated by a fast, scalable, and cost-effective electrophoretic deposition for supercapacitor applications. NiCo 2 O 4 /PANI/rGO composite electrode went through heat treatment under nitrogen to carbonize PANI after electrophoretic deposition. NiCo 2 O 4 platelets, distributed on carbonized polyaniline−rGO network, were active in charge storage with high capacitance, excellent rate capability (1235 F g −1 at 60 A g −1 ), and acceptable cycling stability (3000 cycles at 10 A g −1 ) in a three-electrode assembly. The practical application of the composite electrode was investigated by an all-solid-state asymmetric supercapacitor cell using NiCo 2 O 4 /C-PANI/rGO as the cathode and activated carbon as the anode with specific capacitance of 262.5 F g −1 at 1 A g −1 and a good capacitance retention of 78% after 3500 cycles at an expanded working potential of 1.5 V. This work shows the importance of the composite assembly process that governs the microstructure of the composite.

No abstract

Highly porous Co3O4/NiCo2O4 nanostructures were synthesized using zeolitic imidazolate framework-67 (ZIF-67) nanocrystals. The oxide composite structure was adjusted by modifying ZIF-67 crystallite size and the pore structure by the coordination modulation method. After forming the zeolite imidazolate framework-67 (ZIF-67)/Ni–Co layered double hydroxide intermediate composite through reaction with nickel nitrate, the intermediate composite was heated in air to result in Co3O4/NiCo2O4. Nitrogen adsorption was used for pore structure characterization of the template and resultant oxide composite. The maximum capacitance of nanostructured Co3O4/NiCo2O4 was 770 F g–1 at a discharge current density of 1 A g–1 with acceptable cycle stability, maintaining 70% of the initial capacitance after 10,000 charge–discharge cycles.

No abstract

The present research and development for lubricant production from vegetable oils rely on traditional (trans)esterification, etherification, and/or chemical modifications of triglycerides and free fatty acids (FFAs). However, the final products suffer from at least one of the following: poor low-temperature characteristics, low oxidation stability, low viscosity index, or poor solubility of additives. This study presents a novel approach to produce biolubricants (BL) from the reaction of waste cooking oil (WCO) and cyclic oxygenated hydrocarbons (COHCs) (cyclopentanone, cyclopentanol, anisole, and 2methylfuran) via a four-step pathway: hydrolysis, dehydration/ ketonization, Friedel−Crafts (FC) acylation/alkylation, and hydrotreatment. Such reactions were successfully demonstrated using model compounds (oleic acid and stearic acid) and actual WCO feedstock. The process resulted in the production of novel BLs that were consisted of molecules with several mutual properties: (1) long and linear hydrocarbon chains, (2) low to zero unsaturation, (3) minimal branching, (4) naphthenic rings and cyclic structures, and (5) polar molecules. We showed that such BLs can be synthesized with pour-point, kinematic viscosity (at 40 °C), viscosity index, and Noack volatility of −12 °C, 47.5 cP, 186, and 17 wt %, respectively.