Effect of Pt pre-sintering on the durability of PtPd/Al2O3 catalysts for CH4 oxidation

Lee, Jaekyoung; Kim, Mi Young; Jeon, Jun Hong; Lee, Dae Hyeong; Rao, Komateedi N.; Oh, Dong Gun; Jang, Eun Jeong; Kim, Eun-Seok; Na, Seung Chul; Han, Hyun Sik; Kwak, Ja Hun

doi:10.1016/j.apcatb.2019.118098

Cited by 38 publications

(30 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The similar synergistic effect is observed for the Pd-Ni catalysts in the oxidation of CO [27] and for Pt-Pd/Al 2 O 3 -MnO x catalysts in the oxidation of CO, CH x [28]. It has been shown that the formation of a Pd-Pt alloy could significantly increase the stability of the catalysts in the total oxidation of methane [29][30][31][32][33].…”

Section: Introductionsupporting

confidence: 59%

“…In the case of bimetallic catalysts, the active component could exist in the form of separated monometallic nanoparticles, be an alloy of metals, or have a so-called "core-shell" structure. Moreover, the structure of nanoparticles can change under the influence of reaction conditions [7,31,[34][35][36][37]. The understanding of the atomic structure of the active component and its evolution under the reaction conditions is necessary to develop highly active and stable catalysts.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Atomic Structure of Pd-, Pt-, and PdPt-Based Catalysts of Total Oxidation of Methane: In Situ EXAFS Study

et al. 2021

View full text Add to dashboard Cite

In this study, 3%Pd/Al2O3, 3%Pt/Al2O3 and bimetallic (1%Pd + 2%Pt)/Al2O3 catalysts were examined in the total oxidation of methane in a temperature range of 150–400 °C. The evolution of the active component under the reaction conditions was studied by transmission electron microscopy and in situ extended X-ray absorption fine structure (EXAFS) spectroscopy. It was found that the platinum and bimetallic palladium-platinum catalysts are more stable against sintering than the palladium catalysts. For all the catalysts, the active component forms a “core-shell” structure in which the metallic core is covered by an oxide shell. The “core-shell” structure for the platinum and bimetallic palladium-platinum catalysts is stable in the temperature range of 150–400 °C. However, in the case of the palladium catalysts the metallic core undergoes the reversible oxidation at temperatures above 300 °C and reduced to the metallic state with the decrease in the reaction temperature. The scheme of the active component evolution during the oxidation of methane is proposed and discussed.

show abstract

Section: Introductionsupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Atomic Structure of Pd-, Pt-, and PdPt-Based Catalysts of Total Oxidation of Methane: In Situ EXAFS Study

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Pd catalysts are easily deactivated when Pd is present alone. Thus, to achieve better durability, Pt is often incorporated into Pd catalysts, resulting in tolerance to H 2 O and sulfur. − Because of the different decomposition temperatures of PdO and PtO 2 , Pd remains in the PdO phase up to 800 °C in air, whereas the Pt is favored metallic phase under the same conditions. − Therefore, the active sites vary with reaction conditions where Pd and Pt show high activity under lean or rich conditions, respectively. − Contradictory results have also reported that Pt addition to Pd catalysts shows increased or decreased catalytic activity affected by different Pt/Pd compositions. Some studies reported that the incorporation of an appropriate amount of Pt into Pd results in significantly improved catalytic performance by maintaining the metallic Pd state even under lean conditions. ,,− …”

Section: Introductionmentioning

confidence: 99%

“…Thus, much effort has been devoted to understanding the nature of the active sites of Pt–Pd bimetallic catalysts for CH 4 oxidation. Lee et al reported that a PdO surface layer on top of the Pt clusters is needed for high activity and long-term durability during CH 4 oxidation . Recently, Nie et al suggested that a thin PdO shell covering a Pt-rich core cluster is formed after oxidative pretreatment and that this leads to high CH 4 oxidation activity by stabilizing the transition state (H 3 C δ− Pd 2+ H δ+ O 2– ) ⧧ on Pd 2+ –O 2– pair sites .…”

Section: Introductionmentioning

confidence: 99%

CH₄ Oxidation Activity in Pd and Pt–Pd Bimetallic Catalysts: Correlation with Surface PdO_x Quantified from the DRIFTS Study

Jang

Lee

et al. 2021

ACS Catal.

Self Cite

View full text Add to dashboard Cite

For Pd-based catalysts, facile and fast interconversion between Pd and PdO occurs continuously during the CH 4 oxidation reaction, which makes it challenging to determine active sites. Herein, we report that the amount of partially oxidized palladium (PdO x ) on the catalyst surface shows a linear correlation with the CH 4 oxidation activity in a series of Pd/Al 2 O 3 and Pt− Pd/Al 2 O 3 catalysts hydrothermally aged under commercially relevant conditions. We characterized the amount of surface PdO x through diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) using CO as a probe molecule. With careful consideration that the redox cycle of Pd particles occurs continuously during the CH 4 oxidation reaction, the Pd/Al 2 O 3 catalysts were reoxidized before obtaining the CO adsorption DRIFTS data to minimize the discrepancy between the catalytically relevant phases and the characterized surface composition. The IR spectra of CO adsorption on reoxidized Pd/Al 2 O 3 catalysts contain peaks at 2135−2145 cm −1 , which correspond to PdO x . The steady-state CH 4 oxidation activities at 300 °C increased proportionally with the normalized surface PdO x . Furthermore, Pt−Pd bimetallic catalysts also showed the same linear correlation between the surface PdO x and CH 4 oxidation activity irrespective of composition, preparation method, and support. Our results indicate that the surface PdO x plays a critical role in determining CH 4 oxidation activity rather than the electronic properties of Pd. Overall, we report a general correlation between the amount of surface PdO x and the steady-state CH 4 oxidation activities in various Pd-based catalysts. This work will greatly help in achieving the fundamental understanding of the CH 4 oxidation reaction on the PdO x surface and the further development of Pd-based catalysts for CH 4 oxidation with better activity.

show abstract

“…Methane (CH 4 ), a gas that contributes 20 times as much to the greenhouse effect as carbon dioxide, 1–3 has nearly doubled in the air since the pre‐industrial era 4,5 . The total oxidation of CH 4 is an effective technology to mitigate industrial CH 4 emission, including exhaust of natural gas engines and gas exploitation 6–8 .…”

Section: Introductionmentioning

confidence: 99%

Low‐temperature total oxidation of methane by pore‐ and vacancy‐engineered NiO catalysts

et al. 2022

View full text Add to dashboard Cite

Designing methane combustion catalysts operated under low temperature (<400°C) remains a huge challenge, especially for noble‐metal–free catalytic systems. With NaCl as a crystalline scaffold, NiO catalyst with abundant oxygen vacancies and an ultra‐high–specific surface area of 181 m2 g−1 is obtained. The mesoporous NiO exhibits outstanding CH4 combustion performance (T90 = 370°C at the weight hourly space velocity (WHSV) = 20,000 mL g−1 h−1). X‐ray photoelectron spectroscopy (XPS), H2‐temperature‐programmed reduction (TPR), kinetic measurements, and O18 isotope‐labeling experiments together disclose the key role of surface lattice oxygen and reaction mechanism by NiO catalysts. More importantly, the excellent stability of NiO by doping La was obtained (low‐temperature thermal stability: 385°C, 400 h, 4 vol% H2O).

show abstract

Effect of Pt pre-sintering on the durability of PtPd/Al2O3 catalysts for CH4 oxidation

Cited by 38 publications

References 36 publications

Atomic Structure of Pd-, Pt-, and PdPt-Based Catalysts of Total Oxidation of Methane: In Situ EXAFS Study

Atomic Structure of Pd-, Pt-, and PdPt-Based Catalysts of Total Oxidation of Methane: In Situ EXAFS Study

CH₄ Oxidation Activity in Pd and Pt–Pd Bimetallic Catalysts: Correlation with Surface PdO_x Quantified from the DRIFTS Study

Low‐temperature total oxidation of methane by pore‐ and vacancy‐engineered NiO catalysts

Contact Info

Product

Resources

About

Effect of Pt pre-sintering on the durability of PtPd/Al2O3 catalysts for CH4 oxidation

Cited by 38 publications

References 36 publications

Atomic Structure of Pd-, Pt-, and PdPt-Based Catalysts of Total Oxidation of Methane: In Situ EXAFS Study

Atomic Structure of Pd-, Pt-, and PdPt-Based Catalysts of Total Oxidation of Methane: In Situ EXAFS Study

CH4 Oxidation Activity in Pd and Pt–Pd Bimetallic Catalysts: Correlation with Surface PdOx Quantified from the DRIFTS Study

Low‐temperature total oxidation of methane by pore‐ and vacancy‐engineered NiO catalysts

Contact Info

Product

Resources

About

CH₄ Oxidation Activity in Pd and Pt–Pd Bimetallic Catalysts: Correlation with Surface PdO_x Quantified from the DRIFTS Study