Pt anchored in the skeleton of rice husk-based ZSM-5 for excellent catalytic VOC oxidation: structure-activity relationship and environmental impact assessment

• Published in: Green chemistry : an international journal and green chemistry resource : GC 2024-04, Vol.26 (7), p.451-464
• Main Authors: Lan, Wenxin, Shen, Muping, Chen, Yinye, Niu, Kui, Zhou, Weiming, Xu, Jing, Huang, Baoquan, Cai, Hongjie, Zuo, Jiachang, Lin, Daifeng, Luo, Yongjin, Qian, Qingrong, Chen, Qinghua
• Format: Article
• Language: English
• Subjects: Alcohols; Benzyl alcohol; Carbon footprint; Catalysts; Catalytic oxidation; Chemical synthesis; Environmental impact; Environmental impact assessment; Lewis acid; Life cycle analysis; Life cycle assessment; Molecular sieves; Oxidation; Platinum; Resource utilization; Rice; Silica; Silicon dioxide; Templates; Toluene; Water resistance; Water vapor; Water vapour
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d3gc04482c

ZSM-5 molecular sieves (ZSM-5-T1, ZSM-5-T2, ZSM-5-T3) were synthesized using SiO 2 , SiO 2 -8.7% C, and SiO 2 -23.6% C as templates from rice husk powder, respectively. Pt species were fixed within the ZSM-5 skeleton via the isovolumetric impregnation method, and the resulting catalysts were employed for the efficient oxidation of toluene (C 7 H 8 ). Notably, Pt/ZSM-5-T2 exhibited the highest C 7 H 8 catalytic oxidation activity ( R 175 °C = 0.733 μmol g −1 s −1 , WHSV = 60 000 mL h −1 g −1 ) among the three variants. Furthermore, this catalyst displayed excellent water resistance when exposed to various concentrations of water vapor (2 vol%, 5 vol%, 8 vol% and 10 vol%) during the activity test. The characterization results provided insight into the exceptional catalytic performance of the Pt/ZSM-5-T2 catalyst, attributing it to its high specific surface area, appropriate hydrophilicity, abundant Lewis acid sites, and a high Pt 0 /(Pt 0 + Pt 2+ ) ratio. In situ DRIFTS analysis further suggested that the key step in the oxidation of C 7 H 8 to benzyl alcohol involves C-H cleavage on Pt/ZSM-5. Simultaneously, the application of a life-cycle assessment (LCA) revealed that this strategy, involving the substitution of chemicals with biomass, led to a remarkable 41-43% reduction in carbon footprint. This environmentally friendly approach underscores the potential for repurposing rice husk powder waste. Pt/ZSM-5-T2 meets the requirements for practical applications, paving the way for sustainable resource utilization in the realm of environmental preservation. Pt anchored in rice husk based ZSM-5 with superior catalytic VOC oxidation capability is environmentally friendly, achieving green resource utilization and pollution control.