Heterogeneous catalysts play a dual role in transesterification due to their advantages of being separable and reusable. In recent years, heterogeneous catalysts derived from renewable resources have received more attention. In this paper, the production of biodiesel from Xanthoceras sorbifolia bunge oil via transesterification was studied under the action of an ILe@Cu@MOF catalyst. Fourier-Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, scanning electron microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Thermogravimetric (TG) and other characterization methods were used to characterize the microstructure and thermal stability of the catalyst and further study the ILe@Cu@MOF catalyst for the preparation of biodiesel from Xanthoceras sorbifolia bunge oil. The results show that the surface of the ILe@Cu@MOF catalyst is attached with a sheet-like structure of isoleucine (ILe), which mainly contains Cu, O, C and N elements. The specific surface area is 19.687 m²/g, and the average pore size is 31.74 nm, which belongs to mesoporous material. The pyrolysis temperature of ILe@Cu@MOF reached 360 °C, indicating that the grafting of ILe had a protective effect on Cu@MOF and increased the pyrolysis temperature of Cu@MOF. At the same time, the water contact angle increased from 86° to 121°, and the material was hydrophobic. The optimum conditions for the preparation of biodiesel were as follows: the amount of catalyst was 3 wt%, the molar ratio of methanol to oil was 35:1, the reaction temperature was 50 °C, and the reaction time was 4 h. At this time, the biodiesel yield was up to 82.85%. Moreover, after five cycles of ILe@Cu@MOF, the yield still reached 73.4%. GC–MS and MNR studies showed that the quality of biodiesel after catalysis was higher. The prepared catalyst can make biodiesel products more sustainable, environmentally friendly and economical, and can provide future prospects for the energy utilization of renewable resources.

The swift exhaustion of natural oil reserves and worsening environmental issues have prompted the quest for an economical method to produce biofuels. The superiority of heterogeneous catalysis promotes the development of bio-based catalysts. Carbon materials prepared from agricultural and forestry biomass waste have good application prospects in catalysis. In the present study, Xanthoceras sorbifolia shell waste was used as the raw material, Xanthoceras sorbifolia Bunge Carbon (XC) was used as the catalyst carrier, and K₂CO₃ was used as the activator to prepare a heterogeneous catalyst (KXC). The heterogeneous catalyst was characterized by scanning electron microscopy-energy dispersion X-ray spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) and X-ray photoelectron spectroscopy (XPS) analysis techniques to evaluate its chemical composition, structure, and physical morphology. EDS and XPS revealed the presence of K metal, which provided an alkaline site for the transesterification reaction to produce biodiesel. The biodiesel yield was observed by gas chromatography−mass spectrometry (GCMS). Under the reaction conditions of a methanol-to-oil molar ratio of 12:1, a reaction time of 90 min, a temperature of 65 °C, and a catalyst loading of 4 wt.% using 25KXC-600-4, the yield of biodiesel can reach 95.13 ± 0.82%. After being repeated five times, the yield was still 58.11 ± 3.80%. The catalyst has no waste generation, and has the characteristics of simple preparation and environmental friendliness, which make it a green heterogeneous catalyst for biodiesel production.

As a key medium in industry, lubricating oil plays a significant role in reducing friction, cooling sealing and transmitting power, which directly affects equipment life and energy efficiency. Traditional mineral-based lubricating oils rely on non-renewable petroleum, and they have high energy consumption and poor biodegradability ( −10 °C), and easy precipitation of wax crystals at low temperature, which restricts their industrial application. In recent years, a series of modification studies have been carried out around “pour point depression-viscosity preservation”. Catalytic isomerization can reduce the freezing point to −42 °C while maintaining a high viscosity index. Epoxidation–ring-opening modification introduces branched chains or ether bonds, taking into account low-temperature fluidity and oxidation stability. The deep dewaxing-isomerization dewaxing process improves the base oil yield, and the freezing point drops by 30 °C. The synergistic addition of polymer pour point depressant and nanomaterials can further reduce the freezing point by 10–15 °C and improve the cryogenic pumping performance. The life cycle assessment shows that using the “zero crude oil” route of waste oil and green hydrogen, the carbon emission per ton of lubricating oil is only 0.32 t, and the cost gradually approaches the level of imported synthetic esters. In the future, with the help of biorefinery integration, enzyme catalytic modification and AI molecular design, it is expected to realize high-performance, low-cost, near-zero-carbon lubrication solutions and promote the green transformation of industry.