Nano-Array Integrated Structured Catalysts: A New Paradigm upon Conventional Wash-Coated Monolithic Catalysts?

Journal Article · 28 August 2017 · Catalysts

DOI: https://doi.org/10.3390/catal7090253 · OSTI ID:1425390

Weng, Junfei ^[1]; Lu, Xingxu ^[2]; Gao, Pu-Xian ^[2]

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1. Univ. of Connecticut, Storrs, CT (United States); University of Connecticut
2. Univ. of Connecticut, Storrs, CT (United States)

The monolithic catalyst, namely the structured catalyst, is one of the important categories of catalysts used in various fields, especially in catalytic exhaust after-treatment. Despite its successful application in conventional wash-coated catalysts in both mobile and stationary catalytic converters, washcoat-based technologies are facing multi-fold challenges, including: (1) high Pt-group metals (PGM) material loading being required, driving the market prices; (2) less-than ideal distribution of washcoats in typically square-shaped channels associated with pressure drop sacrifice; and (3) far from clear correlations between macroscopic washcoat structures and their catalytic performance. To tackle these challenges, the well-defined nanostructure array (nano-array)-integrated structured catalysts which we invented and developed recently have been proven to be a promising class of cost-effective and efficient devices that may complement or substitute wash-coated catalysts. This new type of structured catalysts is composed of honeycomb-structured monoliths, whose channel surfaces are grown in situ with a nano-array forest made of traditional binary transition metal oxide support such as Al₂O₃, CeO₂, Co₃O₄, MnO₂, TiO₂, and ZnO, or newer support materials including perovskite-type ABO3 structures, for example LaMnO₃, LaCoO₃, LaNiO, and LaFeO₃. The integration strategy parts from the traditional washcoat technique. Instead, an in situ nanomaterial assembly method is utilized, such as a hydro (solva-) thermal synthesis approach, in order to create sound structure robustness, and increase ease and complex-shaped substrate adaptability. Specifically, the critical fabrication procedures for nano-array structured catalysts include deposition of seeding layer, in situ growth of nano-array, and loading of catalytic materials. The generic methodology utilization in both the magnetic stirring batch process and continuous flow reactor synthesis offers the nano-array catalysts with great potential to be scaled up readily and cost-effectively. The tunability of the structure and catalytic performance could be achieved through morphology and geometry adjustment and guest atoms and defect manipulation, as well as composite nano-array catalyst manufacture. Excellent stabilities under various conditions were also present compared to conventional wash-coated catalysts.

• Research Organization: Univ. of Connecticut, Storrs, CT (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: EE0000210; EE0006854
• OSTI ID: 1425390
• Journal Information: Catalysts, Journal Name: Catalysts Journal Issue: 12 Vol. 7; ISSN CATACJ; ISSN 2073-4344
• Publisher: MDPICopyright Statement
• Country of Publication: United States
• Language: English