Radio-frequency H2 plasma treatment of AuPd/TiO2 catalyst for selective hydrogenation of acetylene in excess ethylene

A review of the advances in catalyst modification using nonthermal plasma: Process, Mechanism and Applications

With the continuous development of catalytic processes in chemistry, biology, organic synthesis, energy generation and many other fields, the design of catalysts with novel properties has become a new paradigm in both science and industry. Nonthermal plasma has aroused extensive interest in the synthesis and modification of catalysts. An increasing number of researchers are using plasma for the modification of target catalysts, such as modifying the dispersion of active sites, regulating electronic properties, enhancing metal-support interactions, and changing the morphology. Plasma provides an alternative choice for catalysts in the modification process of oxidation, reduction, etching, coating, and doping and is especially helpful for unfavourable thermodynamic processes or heat-sensitive reactions. This review focuses on the following points: (i) the fundamentals behind the nonthermal plasma modification of catalysts; (ii) the latest research progress on the application of plasma modified catalysts; and (iii) main challenges in the field and a vision for future development.

Atomically Dispersed Pd Atoms on a Simple MgO Support with an Ultralow Loading for Selective Hydrogenation of Acetylene to Ethylene

We report a simple and efficient Pd/MgO catalyst loaded with ppm level of Pd (7.8 ppm) for semi-hydrogenation of acetylene to ethylene. The catalyst showed excellent performance with high acetylene conversion (97%), high ethylene selectivity (89%) and good stability. Moreover, the atomically dispersed Pd atoms are inactive for ethylene hydrogenation. Isotopic and FTIR results suggest that H₂ dissociates at isolated Pd atoms in a heterolytic manner forming O-H bond, which may account for the high selectivity.

Au@Pt Nanotubes within CoZn-Based Metal-Organic Framework for Highly Efficient Semi-hydrogenation of Acetylene

Designing nanocatalysts with synergetic functional component is a desirable strategy to achieve both high activity and selectivity for industrially important hydrogenation reaction. Herein, we fabricated a core-shell hollow Au@Pt NTs@ZIFs (ZIF, zeolitic imidazolate framework; NT, nanotube) nanocomposite as highly efficient catalysts for semi-hydrogenation of acetylene. Hollow Au@Pt NTs were synthesized by epitaxial growth of Pt shell on Au nanorods followed with oxidative etching of Au@Pt nanorod. The obtained hollow Au@Pt NTs were then homogeneously encapsulated within ZIFs through in situ crystallization. By combining the high activity of bimetallic nanotube and gas enrichment property of porous metal-organic frameworks, hollow Au@Pt NT@ZIF catalyst was demonstrated to show superior catalytic performance for the semi-hydrogenation of acetylene, in terms of both selectivity and activity, over those of monometallic Au and solid bimetal nanorod@ZIF counterparts. This catalysts design idea is believed to be inspirable for the development of highly efficient nanocomposite catalysts.

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Core-shell nanocomposite catalysts M@ZIFs are assembled

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The M NRs and NTs are well dispersed and fully encapsulated in ZIF-67 and ZIF-8

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Au@Pt_NT enhance the selectivity and conversion for the semi-hydrogenation of acetylene

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DFT calculations show Au@Pt_NT has lower energy barrier compared with Au@Pt_NR

Selectivity boost in partial hydrogenation of acetylene via atomic dispersion of platinum over ceria

High-throughput flame spray pyrolysis affords a low-loading Pt catalyst supported on cerium oxide, which is an excellent material for selective C₂H₂ semihydrogenation at 180 °C, with near-complete conversion and high selectivity towards C₂H₄ (87.1%).

Unravelling the role of active-site isolation in reactivity and reaction pathway control for acetylene hydrogenation

Supported Pd_xCu_y bimetallic catalysts were prepared and characterized to illustrate the active-site isolation effect on controlling the reactivity and reaction pathway of acetylene hydrogenation.

Cold plasmas in the modification of catalysts

Heterogeneous catalysts play an important role in the chemical industry and are also of critical importance in the general well-being of society in the 21st century. Increasing demands are being placed on catalyst performance in a number of areas such as activity, selectivity, longevity, and cost. Conventional approaches to improving catalytic performance are becoming exhausted, and novel ways of generating the increased performance are being sought. The utilization of cold plasmas has opened great opportunities for modification of catalysts, thanks to their room-temperature operations with reduced energy combustion, shortened duration, and undestroyed bulk structure. In this review, we present an assessment of the modification of catalysts by cold plasmas, with emphasis on particle sizes, dispersion of nanoparticles, distribution of elements, electronic properties, acid-base properties, surface functional groups, and metal-support interaction. Moreover, challenges and perspectives are also presented for the further modification of catalysts by cold plasmas and broadening their practical applications.