Hydrogenated nitrile butadiene rubber (HNBR) is a crucial material for high-performance sealing applications; however, conventional solution hydrogenation is often limited by high noble-metal consumption and the challenges in simultaneously achieving high activity, selectivity and stability. Herein, a synergistic design strategy integrating mass transfer enhancement, bimetallic electronic synergy, and support interface stabilization is proposed for efficient NBR hydrogenation. A Pd-Ni bimetallic-doped TiO 2 -Al 2 O 3 porous composite catalyst was synthesized through a sol–gel method, in which the pore size distribution was tuned to 15–18 nm by using an F127 template to facilitate macromolecular diffusion. Partial substitution of Pd with Ni modulates the electronic structure of Pd sites, promoting H 2 dissociation and selective C=C bond hydrogenation, while the TiO 2 -Al 2 O 3 composite support provides Lewis acid–base sites and oxygen vacancies that enhance metal dispersion and catalyst stability. The optimized Pd–1Ni catalyst achieves a hydrogenation degree of 92% at 120 °C and 4 MPa, and retains over 80% of its activity after five consecutive cycles. This work demonstrates an effective strategy for balancing catalytic activity, noble-metal utilization, and operational stability in heterogeneous NBR hydrogenation systems, providing a practical reference for catalyst design in polymer hydrogenation processes.
NO conversion using dielectric barrier discharge (DBD) plasma with different catalysts was investigated. Cu/TiO 2 , Cu/Al 2 O 3 , Cu/ZSM-5, Cu/CNTs and Cu/AC catalysts were prepared by incipient wetness impregnation with 4 wt% Cu loaded. BET, SEM, XRD, XPS, H 2 -TPR, NH 3 -TPD were used to measure and evaluate various catalysts. Compared with the plasma only process, the combination of plasma with different catalysts significant improved the NO conversion rate. The highest NO conversion rate of 76% could be achieved with Cu/ZSM-5 catalyst at the energy density of 184 J/L. The results indicate that Cu species over the support ZSM-5 can produce high concentrations of CuO, largest specific surface area, largest amounts of acidity and lowest reduction temperature (209 °C), these factors conducive to plasma-catalyst reaction. Besides, Cu/TiO 2 and Cu/Al 2 O 3 catalysts exhibited excellent NO conversion at the low energy density because of the low thermal stability. After plasma-catalyst reaction, the reducibility of CuO and Cu 2 O over supports decreased and the peak position of acid sites shifted to lower temperature.
Zheng-Zhe Zhang,Ya-Fei Cheng,Lian-Zeng-Ji Xu,Yu-Hui Bai,Jia-Jia Xu,Zhi-Jian Shi,Yang-Yang Shen,Ren-Cun Jin
The increasing use of engineered metal oxide nanoparticles (MONPs) in consumer products raises great concerns about their environmental impacts, but their potential impacts on anaerobic ammonium oxidation (anammox) process in wastewater treatment remain unclear. In this study, the presence of MONPs (1, 50, 200 mg L −1 ) exhibited no visible effects on the nitrogen removal performance of anammox reactors, but high levels (200 mg L −1 ) of SiO 2 NPs, Al 2 O 3 NPs and CeO 2 NPs had a distinct effect on shaping the anammox community. Long-term exposure of MONPs caused different responses in the relative abundance of Ca. Kuenenia , the level of functional gene Hzs A and the activities of three key enzymes involved in anammox metabolism, but no significant inhibition effects on specific anammox activity were detected. Overall, the effects of MONPs on anammox community structure and sludge properties depended on their types and levels and followed the order SiO 2 > CeO 2 > Al 2 O 3 > TiO 2 .
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