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Liao, Peilin

Publications and source records attributed to Liao, Peilin.

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Multiple redox mechanisms for water-gas shift reaction on Fe 3 O 4 (1 1 1) surface: A density functional theory and mean-field microkinetic modeling study

In this work, we investigated redox mechanisms for the high temperature (HT) water–gas shift reaction (WGSR) on the Fe 3 O 4 (1 1 1) surface using density functional theory (DFT) calculations and mean-field microkinetic modeling (MKM). The redox pathways branched into three Langmuir-Hinshelwood processes (LH1, LH2 and LH3) and one Mars-van-Krevelen (MVK) process (in the presence of oxygen vacancy) from multidentate binding of CO and CO 2 over four available reactive sites (Fe oct2 , Fe tet1 , Fe bridge, and O1). We found that the LH1 and LH2 processes have CO adsorption at a single iron site (Fe oct2 or Fe tet1 ), while the LH3 and MVK processes have stronger chemisorption of CO or CO 2 by both the Fe oct2 site and the O 1 site. From the mechanistic study of these reaction path, we recognized that availability of O 1 sites was key to proceed to either CO oxidation by the single site (LH1, LH2) or by the dual site (LH3, MVK). We observed that the reaction energetics were significantly different in the CO oxidation steps, where the single or dual site results in markedly different apparent activation energy (73–281 kJ/mol) and reaction rates (10 -3 –10 -10 mol∙m -2 ∙s -1 ) among the four reaction mechanisms. The utilization of mean field MKM with DFT reaction energetics helps explain the experimental debates for the catalytic reaction details as well as providing a possible direction to engineer the catalyst with higher activity.

42 ENGINEERING↗
DOE OSTI2021

Catalytic Light Alkanes Conversion through Anaerobic Ammodehydrogenation

Catalytic transformation of light alkanes could have considerable practical value, yet remains one of the most challenging areas in catalysis research due to the inertness of the C–H bond. Here, we proposed an efficient ammodehydrogenation (ADeH) catalytic system for the direct C–N linkage between light alkanes and ammonia for CH 3 CN and H 2 (CO x free) production. This breakthrough is achieved over bifunctional metal-modified HZSM-5 catalysts, through the tandem dehydrogenation–amination–dehydrogenation mechanism. We show that ethane ADeH over the Pt/HZSM-5 catalyst can be realized under atmospheric pressure at temperatures as low as 350 °C. The specific rate of CH 3 CN is ~60 μmol/(g min), and the selectivity is up to 99% under such mild conditions. The yield of CH 3 CN increases with increasing temperature; however, the selectivity decreases due to the formation of HCN, C 2 H 4 , and CH 4 . Additionally, the Pt/HZSM-5 catalyst is coke-resistant during the ADeH owing to the strong interaction between NH 3 and the acid sites of the catalyst. So, we anticipate that the proposed ADeH could be extended for the transformation of various n/iso-alkanes with tunable selectivity to alkene and nitriles.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Facile Synthesis of Pt Carbide Nanomaterials and Their Catalytic Applications

The development of transition metal carbides, for example, Pd carbide, Mo carbide, Co carbide, and Fe carbide for catalytic applications has attracted significant attention. Pt carbide has also been actively pursued, however, no catalytic examinations of Pt carbide have been performed, likely due to its extreme synthesis conditions. In this study, we report a facile synthesis of Pt carbide nanomaterials under mild conditions, for the first time, through ethane treatment of confined Pt nanoclusters under mild temperatures and ambient pressure. Such Pt carbide nanomaterials exhibit remarkable activity in catalytic hydrocarbon conversion, including ethane aromatization and acetylene hydrogenation, and are superior over supported Pt nanoparticles. Our work further reveals that Pt nanoclusters are favored in terms of forming Pt carbide when compared to isolated single Pt atoms and large Pt nanoparticles. This work provides a new approach to prepare metal carbide based catalytic materials through nanoclusters under mild conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Online simulation powered learning modules for materials science

Simulation tools are playing a significant role in materials science and engineering and beyond their well established importance in research and development, these tools have a vital pedagogical potential. We describe a set of online simulation tools and learning modules designed to help students explore important concepts in materials science where hands-on activities with high-fidelity simulations can provide insight not easily acquired otherwise. The online tools, which involve density functional theory and molecular dynamics simulations, have been designed with non-expert end-users in mind and only a few clicks are required to perform most simulations, yet they are powered by research-grade codes and expert users can access advanced options. All tools and modules are available for online simulation in nanoHUB.org and access is open and free of charge. Importantly, instructors and students do not need to download or install any software. The learning modules cover a range of topics from electronic structure of crystals and doping, plastic deformation in metals, and physical properties of polymers. These modules have been utilized in several core undergraduate courses at Purdue’s School of Materials Engineering, they are self contained, and are easy to incorporate into existing classes.

36 MATERIALS SCIENCE↗