Ammonia decomposition over iron-based catalyst: Exploring the hidden active phase

Lü, Bin; Li, Ling; Ren, Menghao; Liu, Yu; Zhang, Yanmin; Xu, Xin; Wang, Xuan; Qiu, Han‐Yue

doi:10.1016/j.apcatb.2022.121475

Cited by 27 publications

(19 citation statements)

References 45 publications

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“…Therefore, the actual working catalyst for the NH 3 decomposition must be Fe x N, although deep nitridation has been found to deactivate the catalyst . According to recent work by Lu et al, the highest NH 3 decomposition activity was observed over the Fe/Fe 4 N mixing phase. The authors suggested that the deposition of an N on the Fe(100) surface modifies the electronic structure of its surrounding iron atoms, causing a significant reduction of the initial dehydrogenation barrier of NH 3 …”

Section: Resultsmentioning

confidence: 99%

Size-Dependent Activity of Iron Nanoparticles in Both Thermal and Plasma Driven Catalytic Ammonia Decomposition

Chen

Cheah

et al. 2022

Ind. Eng. Chem. Res.

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Water-dispersible Fe 3 O 4 nanoparticles with diameters of 4.2 ± 0.6, 6.1 ± 0.8, 8.1 ± 1, and 10.4 ± 1 nm were prepared through the polyol method and employed as the precursors of Fe 3 O 4 /Al 2 O 3 catalysts to study the size-dependent activity. We identified that the activity of the catalysts in NH 3 decomposition (driven by both thermal and dielectric barrier discharge plasma) increased with increasing Fe 3 O 4 particle size. The turnover frequencies (TOFs) were increased from 0.9 to 5.8 s −1 with an increasing Fe 3 O 4 precursor size from 4.2 to 10.4 nm during the thermocatalytic decomposition. A quite similar "particle size effect" was also observed for the plasma catalytic decomposition, although lower TOF was observed. Additionally, reaction-induced catalyst reconstruction was identified during the early-stage of the catalytic decomposition and can be attributed to the nitridation of FeO x to Fe x N. Our results provide new evidence for the "structure-sensitivity" of the catalytic NH 3 decomposition.

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Section: Resultsmentioning

confidence: 99%

Size-Dependent Activity of Iron Nanoparticles in Both Thermal and Plasma Driven Catalytic Ammonia Decomposition

Chen

Cheah

et al. 2022

Ind. Eng. Chem. Res.

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“…We proved that effective NH 3 splitting on the carbon surface was observed on both high-temperature treated materials. This reaction was examined in the literature over Fe and Co containing active sites [ 10 , 21 , 22 ]. However no work was done for pure carbons, nor for NTP conditions.…”

Section: Discussionmentioning

confidence: 99%

“…To our knowledge, only a few studies refer to ammonia decomposition by non-thermal plasma (NTP). Lu et al [ 10 ] investigated the influence of dielectric barrier discharge plasma on the hidden active phase. They compared thermal catalytic ammonia decomposition and splitting in plasma.…”

Section: Introductionmentioning

confidence: 99%

Non-Thermal Ammonia Decomposition for Hydrogen Production over Carbon Films under Low-Temperature Plasma—In-Situ FTIR Studies

Moszczyńska

Liu

Wiśniewski

2022

IJMS

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Due to easy storage and transportation, liquid hydrogen carriers will play a significant role in diversifying the energy supply pathways by transporting hydrogen on a large scale. Thus, in this study, amorphous carbonaceous materials have been employed for hydrogen production via ammonia decomposition under non-thermal plasma (NTP) conditions. The adsorption and splitting of ammonia over carbons differing in the chemical structure of surface functional groups have been investigated by in situ spectral studies directly under NTP conditions. As a result of NH3 physical and chemical sorption, surface species in the form of ammonium salts, amide and imide structures decompose immediately after switching on the plasma environment, and new functionalities are formed. Carbon catalysts are very active for NH3 splitting. The determined selectivity to H2 is close to 100% on N-doped carbon material. The data obtained indicate that the tested materials possess excellent catalytic ability for economical, COx-free hydrogen production from NH3 at a low temperature.

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“…In particular, Febased catalysts have been widely used in the high-temperature ammonia decomposition reaction. [10] Therefore, its application in AOR is also imperative. For example, Xia et al reported a highly activated iron phosphate over-layer on the surface of α-Fe 2 O 3 nanorods as an AOR pre-catalyst, which was converted into FeOOH by a facile electrochemical activation, providing the efficient active sites for the ammonia adsorption process.…”

Section: Introductionmentioning

confidence: 99%

Self‐Terminating Surface Reconstruction Induced by High‐Index Facets of Delafossite for Accelerating Ammonia Oxidation Reaction Involving Lattice Oxygen

Zhang

Jiang

Yan

et al. 2023

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Ammonia (NH3) is a promising hydrogen (H2) carrier for future carbon‐free energy systems, due to its high hydrogen content and easiness to be liquefied. Inexpensive and efficient catalysts for ammonia electro‐oxidation reaction (AOR) are desired in whole ammonia‐based energy systems. In this work, ultrasmall delafossite (CuFeO2) polyhedrons with exposed high‐index facets are prepared by a one‐step NH3‐assisted hydrothermal method, serving as AOR pre‐catalysts. The high‐index CuFeO2 facet is revealed to facilitate surface reconstruction into active Cu‐doped FeOOH nanolayers during AOR processes in ammonia alkaline solutions, which is driven by the favorable Cu leaching and terminates as the 2p levels of internal lattice oxygen change. The reconstructed heterostructures of CuFeO2 and Cu‐doped FeOOH effectively activate the dehydrogenation steps of NH3 and exhibit a potential improvement of 260 mV for electrocatalytic AOR at 10 mA cm−2 compared to the pre‐restructured phase. Further, density functional theory (DFT) calculations confirm that a lower energy barrier of the rate‐determining step (*NH3 to *NH2) is presented on high‐index CuFeO2 facets covered with Cu‐doped FeOOH nanolayers. Innovatively, lattice oxygen atoms in Fe‐based oxides and oxyhydroxide are involved in the dehydrogenation steps of AOR as a proton acceptor, broadening the horizons for rational designs of AOR catalysts.

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Ammonia decomposition over iron-based catalyst: Exploring the hidden active phase

Cited by 27 publications

References 45 publications

Size-Dependent Activity of Iron Nanoparticles in Both Thermal and Plasma Driven Catalytic Ammonia Decomposition

Size-Dependent Activity of Iron Nanoparticles in Both Thermal and Plasma Driven Catalytic Ammonia Decomposition

Non-Thermal Ammonia Decomposition for Hydrogen Production over Carbon Films under Low-Temperature Plasma—In-Situ FTIR Studies

Self‐Terminating Surface Reconstruction Induced by High‐Index Facets of Delafossite for Accelerating Ammonia Oxidation Reaction Involving Lattice Oxygen

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