Origin of Higher CO Oxidation Activity of Pt/Rutile than That of Pt/Anatase

Kim, Haneul; Kim, Joonwoo; Kwak, Ja Hun

doi:10.1021/acs.jpcc.3c00159

Cited by 5 publications

(3 citation statements)

References 51 publications

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“…For the x PtCe 2 samples, the gaseous CO 2 band was observed in the 2300–2400 cm –1 region, indicating that C 3 H 8 was completely oxidized after Pt loading. As shown in Figure b, for the 1.3PtCe catalyst, in addition to methoxy species, acetate, and formate, a new peak at 2110 cm –1 assigned to the CO adsorbed on partially positively charged Pt sites (Pt δ+ ) was detected, , which corresponds to the results of XPS and XAS. The band of CO remained under O 2 /Ar conditions, indicating that CO can firmly be adsorbed on the Pt δ+ and prevent the activation of C 3 H 8 or O 2 .…”

Section: Resultssupporting

confidence: 53%

“…Meanwhile, for the CeO 2 (100) supported 5.0 nm Pt NPs catalyst, a higher frequency CO vibrational stretch at 2091 cm –1 emerged. Considering that the larger Pt NPs predominantly exist in a metallic state, this vibrational stretch can be attributed to CO bound to metallic Pt with WC sites. , When the size increased to 7 nm, only the main CO vibrational stretch at 2088 cm –1 can be observed, indicating more metallic Pt with WC sites produced. − …”

Section: Resultsmentioning

confidence: 99%

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Revealing the Size Effect of Ceria Nanocube-Supported Platinum Nanoparticles in Complete Propane Oxidation

Ge,

Fan,

Tang

et al. 2024

ACS Catal.

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The elimination of propane is one of the key tasks in reducing volatile organic compounds (VOCs) and automotive exhaust emissions. The platinum nanoparticle (NP) is a promising catalyst for propane oxidation, while the study of its structural characteristics and functionality remains in its infancy. In this work, we synthesized the nanocubes CeO 2 with a well-defined (100) facet supporting Pt NPs with various sizes, from 1.3 to 7 nm, and systematically investigated the effect of the Pt size on complete propane oxidation efficiency. In particular, CeO 2 (100) supported Pt NPs smaller than 4 nm promote the formation of positively charged Pt sites, which hinder the adsorption and activation of propane and reduce the intrinsic activity for propane oxidation. Consequently, within this size range, the catalytic performance is primarily influenced by the electronic state of the Pt species, with metallic Pt being identified as the active site for the reaction. Conversely, as the particle size exceeds 4 nm, metallic Pt particles become dominant and the geometric structure starts to influence the activity as well. Such entanglement of electronic and geometric factors gives rise to a volcano relationship between reaction rates and Pt particle sizes ranging from 1.3 to 7 nm, while an increased correlation can be observed between the turnover frequencies and the particle sizes in this range. This knowledge can guide the synthesis of highly active catalysts, enabling the efficient oxidation of VOCs with reduced precious metal loadings.

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Section: Resultssupporting

confidence: 53%

Section: Resultsmentioning

confidence: 99%

Revealing the Size Effect of Ceria Nanocube-Supported Platinum Nanoparticles in Complete Propane Oxidation

Ge,

Fan,

Tang

et al. 2024

ACS Catal.

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“…The in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) spectra of CO adsorption at 25 °C for Pt-mpCe/TiO 2 - x catalysts show two bands at 2120 and 2070–2090 cm –1 (Figure A), which are assigned to CO adsorbed on the single Pt atoms , and linearly adsorbed CO on metallic Pt/Pt cluster sites, − respectively. In comparison, the intensity of the band at 2120 cm –1 corresponding to single Pt atoms becomes stronger for the Pt-mpCe/TiO 2 - x catalysts than that for Pt-mpTiO 2 , demonstrating the high dispersion of Pt species on Pt-mpCe/TiO 2 - x with Ce-doping.…”

Section: Resultsmentioning

confidence: 99%

Bottom-Up Construction of Mesoporous Cerium-Doped Titania with Stably Dispersed Pt Nanocluster for Efficient Hydrogen Evolution

Gao,

Ma,

et al. 2024

ACS Appl. Mater. Interfaces

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Hydrogen generation is one of the crucial technologies to realize sustainable energy development, and the design of advanced catalysts with efficient interfacial sites and fast mass transfer is significant for hydrogen evolution. Herein, an in situ coassembly strategy was proposed to engineer a cerium-doped ordered mesoporous titanium oxide (mpCe/TiO 2 ), of which the abundant oxygen vacancies (O v ) and highly exposed active pore walls contribute to good stability of ultrasmall Pt nanoclusters (NCs, ∼ 1.0 nm in diameter) anchored in the uniform mesopores (ca. 20 nm). Consequently, the tailored mpCe/TiO 2 with 0.5 mol % Ce-doping-supported Pt NCs (Pt-mpCe/TiO 2 -0.5) exhibits superior H 2 evolution performance toward the water−gas shift reaction with a 0.73 mol H2 •s −1 •mol Pt −1 H 2 evolution rate at 200 °C, which is almost 6-fold higher than the Pt-mpTiO 2 (0.13 mol H2 • s −1 •mol Pt −1 H 2 ). Density functional theory calculations confirm that the structure of Ce-doped TiO 2 with Ce coordinated to six O atoms by substituting Ti atoms is thermodynamically favorable without the deformation of Ti−O bonds. The O v generated by the six O atom-coordinated Ce doping is highly active for H 2 O dissociation with an energy barrier of 2.18 eV, which is obviously lower than the 2.37 eV for the control TiO 2 . In comparison with TiO 2 , the resultant Ce/TiO 2 support acts as a superior electron acceptor for Pt NCs and causes electron deficiency at the Pt/support interface with a 0.17 eV downshift of the Pt d-band center, showing extremely obvious electronic metal−support interaction (EMSI). As a result, abundant and hyperactive Ti 3+ -O v (-Ce 3+ )-Pt δ+ interfacial sites are formed to significantly promote the generation of CO 2 and H 2 evolution. In addition, the stronger EMSI between Pt NCs and mpCe/TiO 2 -0.5 than that between Pt and mpTiO 2 contributes to the superior self-enhanced catalytic performance during the cyclic test, where the CO conversion at 200 °C increases from 72% for the fresh catalyst to 99% for the used one. These findings reveal the subtle relationship between the mesoporous metal oxide-metal composite catalysts with unique chemical microenvironments and their catalytic performance, which is expected to inspire the design of efficient heterogeneous catalysts.

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The dynamic catalysis of Ga/ZSM-5 catalysts for propane-CO2 coupling conversion to aromatics and syngas

Song,

Hu,

Feng

et al. 2024

Journal of Energy Chemistry

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Origin of Higher CO Oxidation Activity of Pt/Rutile than That of Pt/Anatase

Cited by 5 publications

References 51 publications

Revealing the Size Effect of Ceria Nanocube-Supported Platinum Nanoparticles in Complete Propane Oxidation

Revealing the Size Effect of Ceria Nanocube-Supported Platinum Nanoparticles in Complete Propane Oxidation

Bottom-Up Construction of Mesoporous Cerium-Doped Titania with Stably Dispersed Pt Nanocluster for Efficient Hydrogen Evolution

The dynamic catalysis of Ga/ZSM-5 catalysts for propane-CO2 coupling conversion to aromatics and syngas

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