Ruifeng Li

The Pt/A/HZS- x composite molecular sieve catalysts can regulate not only the number of branches in i-dodecane but also their positions.

Oil-soluble overbased calcium dinonylnaphthalenesulfonate (OB-Ca-DNNS), with favorable anti-wear and acid-neutralizing capacities, was synthesized from dinonylnaphthalenesulfonic acid in this study. A four-ball tribometer was used to evaluate the tribological performance of OB-Ca-DNNS in PAO8 at mass fractions of 0.2 wt %–1.2 wt %. Its synergistic antiwear and corrosion inhibition performance, in combination with zinc dialkyldithiophosphate (ZDDP), was further explored. Combined SEM and EDS analyses were performed to characterize worn surface morphologies and elemental distributions, revealing the underlying antiwear mechanism. At the optimal addition level, OB-Ca-DNNS can reduce the friction coefficient. The optimal dosage of 0.8 wt % provided a wear scar diameter (WSD) of 0.56 mm for GCr15 bearing steel and reduced surface plowing, achieving a corrosion inhibition efficiency of 91.86% for Q235 steel. When compounded with 0.4 wt % ZDDP, the composite system achieved a WSD of 0.28 mm for GCr15 bearing steel and a corrosion inhibition efficiency of 95.14% for Q235 steel. During friction and corrosion inhibition, OB-Ca-DNNS cooperated with ZDDP to form a dense protective film dominated by CaO, FeS, and phosphates. This film isolated direct metal contact, thereby enhancing the synergistic antiwear performance and corrosion inhibition performance.

Upcycling plastic waste into valuable resources without solvents, precious metals, or additional H₂ under mild conditions is a formidable challenge that requires new innovations. Herein, we document a catalyst based on Al₂O₃ beads and zeolite ZSM-5 (ZSM-5#Al₂O₃(2 h)). It cracked polyethylene (PE) into gasoline-range C₄ - C₁₂ hydrocarbons with a selectivity of 98% and a yield of >71% within 1.5 h at 260 °C. Characterization of the catalysts revealed a mesoporous structure and suitable Brønsted acid sites, which promoted the diffusion and catalytic activation of PE. Adjusting the dosage of zeolite supported on Al₂O₃ beads enables regulation of both the number and strength of acidic sites. Theoretical calculations confirmed that the interfacial interaction between zeolite ZSM-5 and Al₂O₃ reduces the acid strength of the composite. This is beneficial for the formation of higher hydrocarbons. Remarkably, the process was performed in a 1 L CSTR unit. These results provide instructive guidance for the design of high-performance catalytic materials used in PE waste recycling.

Na ⁺ ion as charge‐balance agent controlling the distribution of framework aluminum atoms in Y‐zeolite from 1 to 14 Al atoms (Si/Al = 47‐2.4) and the acid strength have been investigated based on DFT computations, descriptors from machine learning, AIMD simulations, and experimental analysis. Different from previous results with proton (H ⁺ ) as charge‐balancing agent preferring next‐nearest‐neighbor Al separation (3N‐Al), the framework Al atoms, in the presence of Na ⁺ ions, prefer larger separations (4N‐Al and 5N‐Al) due to the balance between Na ⁺ /AlO ₄ ⁻ attractive and AlO ₄ ⁻ /AlO ₄ ⁻ repulsive interaction and the preferential occupancy of Na ⁺ ions following the order of six‐membered ring (6MR) > double six‐membered ring (D6R) > four‐membered ring (4MR). The computed sequential substitution enthalpy for 1‐14 Al shows the thermodynamically favorable upper limit of rather low Si/Al ratio (≤ 3) and explains the difficult synthesis of Y‐zeolite with higher Si/Al ratios. Y‐zeolite with non‐exchangeable Na ⁺ ions has stronger acid strength based on the adsorption energy of pyridine and ammonia and exhibits higher catalytic activity in propane cracking.

Electron-rich Ni sites in Ni ₃ Zn–Al ₂ O ₃ drive CO production through monodentate formate decomposition, whereas Zn-evaporation-engineered electron-deficient Ni–Al ₂ O ₃ promotes CH ₄ formation by enabling bidentate formate hydrogenation with abundant *H.

For hierarchical ZSM-11 synthesized by combined low-temperature aging and static crystallization, a higher gel Si/Al ratio has more framework Al in straight channels, thereby suppressing aromatics formation and enhancing propylene selectivity.

This study explores the pyrolysis traits, product distribution and reaction mechanisms of plastics, assesses catalytic effects on process efficiency and product quality, and verifies its circular economy feasibility.