Sub‐5 nm Intermetallic Nanoparticles Confined in Mesoporous Silica Wells for Selective Hydrogenation of Acetylene to Ethylene

Maligal‐Ganesh, Raghu V.; Pei, Yuchen; Xiao, Chaoxian; Chen, Minda; Goh, Tian Wei; Sun, Weijun; Wu, Jiashu; Huang, Wenyu

doi:10.1002/cctc.202000155

Cited by 14 publications

(9 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Catalytic performance of the PtZn iNPs is enhanced by their small size and high monodispersity, as demonstrated in Section . Similarly, using NH 2 -functionalized 200 nm SiO 2 spheres to replace the MWNTs, we synthesized 3.9 ± 0.3 nm PtSn iNPs confined at the interface between the solid SiO 2 sphere core and the mSiO 2 porous shell, representing another approach to obtain small intermetallic catalysts …”

Section: Structural Design Of Silica-encapsulated Inpsmentioning

confidence: 99%

Silica-Encapsulated Intermetallic Nanoparticles for Highly Active and Selective Heterogeneous Catalysis

2021

Self Cite

View full text Add to dashboard Cite

Conspectus Intermetallic nanoparticles (iNPs) have been the subject of many recent reports for their demonstrated applications as highly active and selective heterogeneous catalysts. As a subclass of alloys, intermetallic compounds possess ordered crystal structures and, therefore, well-defined atomic environments, unlike the solid solution of alloys whose atomic arrangements are random and locally unpredictable. Catalytically active iNPs typically contain a group 8–10 transition metals as the “active” metals. They usually also include an “inactive” metal that does not directly participate in the catalytic reaction but can significantly modify the active metal’s behavior. The choice of the inactive metal component can range across the periodic table. A few general challenges remain to design iNPs as heterogeneous catalysts with outstanding performance. Synthetically, the high surface energy of small nanoparticles is prone to their aggregation, while maximizing the surface-to-volume ratios is highly desired for efficient noble metal utilization. Additionally, even though the formation of bulk intermetallic compounds has been extensively studied, the formation of intermetallic phases at the nanoscale can behave differently. For example, the formation temperatures of iNPs are often drastically different from those predicted from the bulk phase diagrams. This behavior often leads to further challenges in the synthesis of iNPs. In addition to synthetic challenges, it is also critical to demonstrate the performance of iNPs in catalysis and establish the structure–property relationships. Instrumental and computational techniques often assist the understanding of catalytic properties. Due to the long-range order of intermetallic structure, various electron and X-ray techniques are often used to precisely determine the structure of iNPs. Structural modeling in density functional theory (DFT) calculation can also benefit from such ordered structures. These techniques have siginificantly improved the understanding of enhanced catalytic properties of iNPs in thermo-, electro-, and photocatalysis. Hydrogenation of furfural to furfuryl alcohol, for example, is a model reaction where PtSn iNPs show enhanced activity and chemoselectivity in hydrogenating CO rather than CC bonds. This superior catalytic performance can be correlated to the change in the geometric and electronic surface structure of the PtSn iNPs based on careful instrumental and computational characterizations. Additionally, intermetallic surfaces can be further modified by ligands or defects. While adding complexity to iNP systems, these modifiers provide additional control over their catalytic properties. In this Account, taking encapsulated iNPs in mesoporous silica as an example, we review the current strategies to develop iNPs as high-performance heterogeneous catalysts, with insights on the distinct formation behavior of iNPs compared to bulk intermetallic materials. We then highlight thermo- and electro-catalysis reactions to which these iNP catalysts a...

show abstract

Section: Structural Design Of Silica-encapsulated Inpsmentioning

confidence: 99%

Silica-Encapsulated Intermetallic Nanoparticles for Highly Active and Selective Heterogeneous Catalysis

2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…To alleviate the sintering during high-temperature annealing, several methods have been invented, such as preparing an anti-sintering coating layer (MgO, SiO 2 , carbon layer, etc.) before annealing, − confining i-NPs in porous structures (porous carbon and MOFs), − and increasing the metal–support interaction with sulfur or nitrogen anchoring. , …”

Section: Introductionmentioning

confidence: 99%

Ordered Intermetallic PtCu Catalysts Made from Pt@Cu Core/Shell Structures for Oxygen Reduction Reaction

Shao

Peng

et al. 2022

Inorg. Chem.

View full text Add to dashboard Cite

Platinum-based ordered intermetallic compounds are promising low-Pt catalysts toward the oxygen reduction reaction (ORR) for high-performance fuel cells. However, the synthesis of ordered intermetallic catalysts usually requires high-temperature annealing to overcome the energy barrier for atom diffusion, which leads to inevitable sintering of catalysts and greatly reduced mass-specific activity. Herein, we developed a new strategy to synthesize PtCu-ordered intermetallic catalysts by the generation of the Pt@Cu core/shell nanoparticles (Pt@Cu NPs) by Pt-assisted H2 reduction of Cu2+ with subsequent annealing at 500–1000 °C. Compared to the commonly used wet-impregnation method, the core/shell structure starts to form ordered PtCu alloys at a lower annealing temperature (500 °C). The Pt@Cu core/shell structure avoids the necessary process of Cu atoms diffusing to Pt NPs across the carbon supports occurred during high-temperature annealing in the wet-impregnation method, which ensures the formation of PtCu NPs with higher ordering degree while annealing at the same temperature. The highly ordered small-sized PtCu catalysts prepared by the core/shell strategy exhibit higher mass activity and specific activity compared to those prepared by the wet-impregnation method. Moreover, a positive correlation between the ORR activity and the ordering degree of the intermetallic PtCu NPs is identified, which could be associated with the increase of compressive strain with the ordering degree.

show abstract

“…Xiao et al confined Pt nanoparticles inside mesoporous SiO 2 wells and proved their stability [23]. Recently, the Pt NPs have been replaced by intermetallic nanoparticles, which were also stable at high temperatures [25]. Tennakoon et al also utilized the mesoporous silica nanoparticles to protect Pt NPs from the harsh environment during the process of upcycling high-density polyethylene [26].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Mesoporous Silica Nanoparticles Loaded with Pt Catalysts

Lyu

Liu

et al. 2022

Catalysts

Self Cite

View full text Add to dashboard Cite

Coating the catalyst with a nanoporous layer has been demonstrated to be an effective approach to improve catalyst stability. Herein, we systematically investigate two types of core-shell mesoporous silica nanoparticles with a platinum nanocatalyst using a variety of characterization methods. One of the mesoporous particles has a unique amine ring structure in the middle of a shell (Ring-mSiO2/Pt-5.0/SiO2), and the other one has no ring structure (mSiO2/Pt-5.0/SiO2). Brunauer–Emmett–Teller/Barrett–Joyner–Halenda (BET/BJH) presented a similar surface area for both particles, and the pore size was 2.4 nm. Ultra-Small-Angle X-ray Scattering (USAXS)/ Small-Angle X-ray Scattering (SAXS) showed the size of mSiO2/Pt-5.0/SiO2 and Ring-mSiO2/Pt-5.0/SiO2 were 420 nm and 272 nm, respectively. It also showed that the ring structure was 30 nm above the silica core. Using high-resolution Transmission Electron Microscopy (TEM), it was found that the platinum nanoparticles are loaded evenly on the surface of the silica. In situ SAXS heating experiments and Thermogravimetric Analysis (TGA) indicated that the mSiO2/Pt-5.0/SiO2 were more stable during the high temperature, while the Ring-mSiO2/Pt-5.0/SiO2 had more change in the particle.

show abstract

Sub‐5 nm Intermetallic Nanoparticles Confined in Mesoporous Silica Wells for Selective Hydrogenation of Acetylene to Ethylene

Cited by 14 publications

References 67 publications

Silica-Encapsulated Intermetallic Nanoparticles for Highly Active and Selective Heterogeneous Catalysis

Silica-Encapsulated Intermetallic Nanoparticles for Highly Active and Selective Heterogeneous Catalysis

Ordered Intermetallic PtCu Catalysts Made from Pt@Cu Core/Shell Structures for Oxygen Reduction Reaction

Synthesis and Characterization of Mesoporous Silica Nanoparticles Loaded with Pt Catalysts

Contact Info

Product

Resources

About