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In order to endow water‐based polyurethane with special functionality, vegetable oil‐based waterborne polyurethane with self‐healing properties is synthesized. Firstly, soybean oil‐based emulsifier (GA‐ESO) was prepared by epoxy soybean oil and glutaric acid without solvent and catalyst. Then, two Diels−Alder (DA) diols were prepared by the DA reaction between N,N′‐(4,4′‐methyldiphenyl) bismaleimide, 4‐maleimide phenol and furfuryl alcohol, respectively. Finally, GA‐ESO and DA diols used as the raw material was reacted with isophorone diisocyanate to synthesize a series of soybean oil‐based waterborne polyurethane with self‐healing behavior. The effects of DA diol on the properties of polyurethane films and the self‐healing process and mechanism of polyurethane membrane were investigated. The results showed that after the addition of DA diol, the particle size of polyurethane emulsion increased from 28.8 to 85.3 nm, the tensile strength was improved from 0.3 to 12.6 MPa, and the water contact angle was enhanced from 68.5° to 84.2°. In addition, it can be observed that with the addition of DAdiol, the polyurethane film had self‐healing behavior at high temperature, and the highest self‐healing efficiency can reach 100%.

In this work, CaO@LiFe 5 O 8 and (CaO-Y 2 O 3 )@LiFe 5 O 8 solid base catalysts were synthesized using LiFe 5 O 8 as the magnetic core to support the active centers. The as-prepared catalysts and commercial CaO were characterized using X-ray diffraction, scanning electronic microscope, and CO 2 -temperatureprogrammed desorption techniques. The results indicated that CaO@LiFe 5 O 8 and (CaO-Y 2 O 3 )@LiFe 5 O 8 solid base catalysts, which could be recycled under the external magnetic field because of their strong magnetism, exhibited better dispersibility and higher total number of basic sites compared with commercial CaO. Additional water and oleic acid were added to the reaction system of palm oil with methanol, and the catalyst was exposed to air to detect its stability in the reaction process. The experiments showed that the (CaO-Y 2 O 3 ) @LiFe 5 O 8 solid base catalyst performed better and possessed not only good water resistance ability but also preferable tolerance to air exposure. In addition, response surface methodology based on the Box-Behnken design was used to optimize the process parameters for the synthesis of biodiesel from palm oil and methanol in the presence of (CaO-Y 2 O 3 )@LiFe 5 O 8 . The optimum process conditions were determined as follows: reaction temperature was 64.96 C, reaction time 4.36 hr, methanol: oil 13, catalyst amount 3.73%, and the highest biodiesel yield reached 96.21%. K E Y W O R D Sbase catalyst, biodiesel, magnetism, response surface methodology, transesterification

The rapid development of high-efficiency and lowprice bifunctional electrocatalysts for replacing precious metal catalysts has been confronted with an enormous challenge for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Here, a three-dimensional cubic electrocatalyst of nickel− iron complex oxides grown on the rich-nitrogen-doped reduced graphene oxide (NiFe 2 O 4 @N-rGO-CC) was synthesized through the two-step hydrothermal reaction. The experimental integrity test revealed that NiFe 2 O 4 @N-rGO-CC exhibited excellent electrocatalytic performance and long-term stability in both alkaline and acid electrolytes. In a 1.0 M potassium hydroxide (KOH) solution, lower overpotentials of 479 and 156 mV were acquired to deliver the current density of 10 mA•cm −2 for both OER and HER, respectively. Besides, NiFe 2 O 4 @N-rGO-CC also exhibited excellent HER performance in 0.5 M H 2 SO 4 solution, which provided a lower overpotential of 188 mV with a current density of 10 mA•cm −2 . NiFe 2 O 4 @N-rGO-CC showed extremely stable durability over a long time period of 30 h for OER and 50 h for HER in alkaline medium, and 40 h for HER in acid medium. Furthermore, NiFe 2 O 4 @N-rGO-CC required only 1.67 V to deliver the current density of 10 mA•cm −2 for alkaline water splitting, and it could be maintained for up to 70 h without any significant potential reduction. As evidenced, rich N-doped rGO modified the carbon cloth, which could significantly increase the electrocatalytic active sites for OER and HER. This work provided a novel approach for synthesizing transition bimetallic oxides grown on rich N-doped rGO-CC electrocatalysts as an innovative application of the lowcost substitution of precious metal electrocatalysts with highly efficient overall water splitting.