Low-temperature VOCs oxidation performance of Pt/zeolites catalysts with hierarchical pore structure.

Different zeolites supported Pt catalysts with micro-mesoporous structure were prepared by organic base tetrapropylammonium hydroxide (TPAOH) treatment and their catalytic oxidation activity for various volatile organic compounds (VOCs) were evaluated. The results reveal that the synergistic effect between Pt nanoparticles and surface acid sites plays an important role in VOCs low-temperature removal. The small size and high dispersion of Pt nanoparticles on the surface of the zeolites would promote the catalytic oxidation of aromatics and alkanes over the Pt/zeolite catalysts, while strong acidity and abundant acid sites of catalysts are in favour of the oxidation of the VOCs containing N and O heteroatoms. In addition, it was found that Pt/ZSM-5 catalyst exhibits the highest oxidation activity for various VOCs low-temperature removal amongst all the catalysts due to the balance of both Pt dispersion and abundant acid sites in the catalyst. This comprehensive consideration should be very helpful when designing and preparing novel catalysts for the low-temperature removal of VOCs.

College students' learning perceptions and outcomes in different classroom environments: A community of inquiry perspective.

Introduction: This study examined the significant differences in Chinese college students' learning perceptions and outcomes between the "quasi smart" and smart classrooms under the perspective of the community of inquiry (CoI) framework. Methods: The participants were 275 freshmen students who took the "college physics" hybrid course in the spring of 2022 at a four-year university in central China. Data were collected from the CoI survey, a follow-up focus group interview with ten randomly selected student participants, and a semi-structured interview with the instructor. Results and discussion: The results indicated that the students' perceptions of the teaching, social, and cognitive presences were significantly higher in the smart classroom than in the "quasi smart" classroom; further, students in the smart classroom achieved significantly higher course marks than those in the "quasi smart" classroom. The pros and cons of these two different classroom environments were identified by the participating students and their course instructor.