Unveiling the crucial active sites responsible for CO, n-heptane, and toluene oxidation over Pt/ZrO2 catalyst

• Published in: Molecular catalysis 2024-04, Vol.558, p.114015, Article 114015
• Main Authors: Zhang, Wen-Xia, Zhao, Xi, Xu, Lin-Ya, Xia, Shuang, Zhou, Yu-Fen, Chen, Chong-Lai, He, Hai-Hua, Luo, Meng-Fei, Chen, Jian
• Format: Article
• Language: English
• Subjects: Catalytic oxidation; Pt chemical state; Pt/ZrO2 catalyst; Surface adsorbed oxygen; Synergistic catalysis
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2024.114015

•Surface Pt specie and adsorbed oxygen on Pt/ZrO2 catalyst are successfully tuned.•Different catalytic behaviors for CO, n-heptane and toluene oxidation were observed on these Pt/ZrO2 catalysts.•Metallic Pt specie and surface adsorbed oxygen is critical for CO oxidation and n-heptane oxidation, respectively.•Synergistic catalysis of metallic Pt specie and surface adsorbed oxygen specie promotes toluene oxidation over the Pt/ZrO2 catalyst. The surface Pt species and adsorbed oxygen on the Pt/ZrO2 catalyst were successfully modulated by altering the preparation methods, resulting in distinct catalytic behaviors for CO, n-heptane, and toluene oxidation. The Pt/ZrO2 catalyst was initially prepared via wetness impregnation and subsequently reduced in an H2 atmosphere to obtain the Pt/ZrO2-R catalyst. In contrast, the Pt/ZrO2-E catalyst was synthesized using ethanol solvent (also serving as a reducing agent) instead of water during wetness impregnation. Moreover, the pre-prepared Pt nanoparticles were loaded onto the ZrO2 surface using polyvinylpyrrolidine (as a protective and structure directing agent) dissolved in ethanol solvent to fabricate the Pt/ZrO2-EP catalyst. Among these catalysts, the Pt/ZrO2-R exhibits superior catalytic activity towards CO oxidation due to its abundant metallic Pt species. It is found that activity of Pt/ZrO2 catalyst for n-heptane oxidation is positively correlated with its surface adsorbed oxygen concentration, thus the highest activity is achieved over the Pt/ZrO2-EP catalyst possessing a higher concentration of surface adsorbed oxygen species. Unlike CO and n-heptane oxidation, toluene oxidation activity is affected by multiple factors, it is primarily promoted by synergistic catalysis between metallic Pt species (Pt0) and surface adsorbed oxygen species over the Pt/ZrO2-EP catalyst. Our preliminary findings underscore that precise modulation of sensitive active sites on surfaces plays a critical role in specific catalytic reactions. [Display omitted]