Lupeng Han

Endogenous growth of 2D AlOOH nanosheets on a 3D Al-fiber network via steam-only oxidation in application for forming structured catalysts

We report a facile, green and generalized method of endogenous growth of 2D boehmite nanosheets (ns) on a 3D network using Al-fibers through oxidation reaction between the Al metal and H2O (2Al + 4H2O = 2AlOOH + 3H2). Such Al-fiber@ns-AlOOH composites have substantial potential applications for microfibrous-structured catalysts and catalytic reactors, being verified by several hot-topic reactions such as CO oxidative coupling to dimethyl oxalate.

A self-supported SS-fiber@meso-HZSM-5 core–shell catalyst via caramel-assistant synthesis toward prolonged lifetime for the methanol-to-propylene reaction

A self-supported SS-fiber@meso-HZSM-5 core–shell catalyst was essentially designed and engineered from micro- to macro-scale by caramel-assistant hydrothermal synthesis. The significant role of caramel during the crystallization process was revealed in detail. Caramel not only created the mesoporosity in the ZSM-5 crystals, but also released acid under hydrothermal synthesis conditions which lowered the zeolite crystallinity. By taking advantage of the mesopore development in a hierarchical micro–meso–macropore structure with favourably-tuned acidic properties, such a catalyst provided a dramatically prolonged lifetime of 845 h (>90% conv.) with high propylene selectivity (e.g., 48%) in the MTP reaction. The hierarchical pore structure development mainly increased the accommodation capacity of the zeolite shell for receiving formed coke thereby leading to a dramatically prolonged lifetime in the MTP reaction.

Copper‐Fiber‐Structured Pd–Au–CuOx: Preparation and Catalytic Performance in the Vapor‐Phase Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

Cu‐fiber‐structured ternary Pd–Au–CuOx catalysts engineered from nano‐ to macro‐scales have been developed for the vapor‐phase dimethyl oxalate (DMO) hydrogenation to ethylene glycol (EG), with the aid of galvanic deposition of Pd and Au onto a thin‐sheet microfibrous structure using 8 μm Cu fiber. Effects of Pd and Au loadings and their ratio have been investigated on the catalyst performance as well as the reaction conditions including reaction temperature and pressure, liquid weight hourly space velocity, and H2/DMO ratio. The promising 0.1 Pd–0.5 Au–CuOx/Cu‐fiber catalyst is capable of converting 97–99 % DMO into EG product at a selectivity of 90–93 %. This catalyst is stable for at least 200 h. The Pd–Au–Cu2O synergistically promotes the hydrogenation activity and stabilizes Cu+ sites to suppress deep reduction deactivation.

Cu-fiber-structured La2O3–PdAu(alloy)–Cu nanocomposite catalyst for gas-phase dimethyl oxalate hydrogenation to ethylene glycol

Structured Pd–Au–CuOx/Cu-fiber obtainable by a galvanic co-deposition method is post-modified by La2O3 and consequently shows promising low-temperature activity and stability for the titled reaction, due to the in situ formation of a La2O3–PdAu(alloy)–Cu nanocomposite in the reaction thereby leading to enhanced ability for H2 activation and H-spillover associated with the La2O3-assisted activation of CO and C–O groups of dimethyl oxalate.

Microfibrous-structured Al-fiber@ns-Al2O3 core–shell composite functionalized by Fe–Mn–K via surface impregnation combustion: as-burnt catalysts for synthesis of light olefins from syngas

Promising microfibrous-structured Al-fiber@ns-Al2O3@Fe–Mn–K catalysts are developed for the mass/heat-transfer limited Fischer–Tropsch synthesis of light olefins. The Al-fiber@ns-Al2O3 core–shell composites, engineered on the nano- to macro-scale, are first prepared by endogenously growing thin shell (∼0.5 μm) nanosheet γ-Al2O3 (ns-Al2O3) onto the 3-dimentional microfibrous-structured network consisting of 10 vol% 60 μm Al-fiber and 90 vol% voidage. After modification by K through an impregnation method, the Al-fiber@ns-Al2O3 composites are functionalized with nano-structured Fe and Mn active components via a surface impregnation combustion method. The effect of combustion atmospheres (air, N2, and N2 followed by air (N2–air)) on the catalyst performance is investigated. The as-burnt catalyst obtained under air delivers the highest iron time yield of 206.0 μmolCO gFe−1 s−1 at 89.6% CO conversion with 42.1%C selectivity to C2–C4 olefins (350 °C, 4.0 MPa, 10 000 mL (g−1 h−1)), while the other two as-burnt catalysts under N2 and N2–air yield relatively low CO conversions of 58–67%. Combustion under air is helpful to form 6 nm Fe–Mn–K oxide particles with better reducibility and carbonization properties thereby leading to high performance. In contrast, under either N2 or N2–air atmosphere, smaller oxide particles (3–4 nm) are formed but suffer from deteriorated reducibility and carbonization properties due to the strong support–metal interaction. Such as-burnt catalysts obtained under air also demonstrate promising stability.