首页|氧吸附诱导ε-Fe2C表面重构的理论研究

氧吸附诱导ε-Fe2C表面重构的理论研究

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基于第一性原理的密度泛函理论(DFT)计算，研究ε-Fe2C表面氧吸附结构，考查不同氧覆盖度(θo)和氧势(μo)条件下的Wulff结构演变，以及氧消除反应机理。结果发现在低氧覆盖度(θo=0。25)和较低氧势(μo＜-7。1 eV)条件下，高活性(1(2)1)表面保持优势占比(55％～90％)，惰性(101)表面占比小于25％。升高氧势和氧覆盖度，ε-Fe2C暴露表面以(2(2)1)和(100)为主。在实际反应条件(300 ℃，1 000 kPa，V(CO)/V(H2)=1)下，其μo约为-7。5 eV，ε-Fe2C表面以(1(2)1)为主，表明其具有抗氧化性能。氧消除反应计算结果显示，(1(2)1)表面易于发生氧消除，能垒为1。33 eV，与Wulff形貌模拟结果一致。
Theoretical study of ε-Fe2C surface reconstruction induced by oxygen adsorption
In this study we performed density functional theory calculations of the adsorption of oxygen on the ε-Fe2C surfaces to investigate the Wulff construction evolution at different oxygen coverage(θo)and potential(μo)as well as the mechanism of oxygen removal.At low oxygen coverage(θo=0.25)and po-tential(μo＜-7.1 eV),the(1(2)1)facets with high activity remain the high exposure(55％to 90％)while the inert(101)facets contribute less than 25％.With increasing the μo and θo,the(2(2)1)and(100)be-come the main exposing facets.Considering the reaction condition(300 ℃,1 000 kPa,V(CO)/V(H2)=1),the po is determined as-7.5 eV.Thus,the ε-Fe2C exposes mainly the(1(2)1)surfaces indicating its antioxidation ability.Oxygen removal mechanisms indicate that the adsorbed oxygen is easily removed on(1(2)1)surface with a barrier of 1.33 eV in good agreement with the simulated Wulff constructions.

iron carbidesurface reconstructionFischer-T ropsch synthesisWulff construction

阮志慧、张煜华、李哲、李金林

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中南民族大学催化转化与能源材料化学教育部重点实验室,催化与材料科学湖北省重点实验室,湖北武汉 430074

ε-Fe2C 表面重构 吸附氧消除反应 Wulff结构

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaFundamental Research Funds for the Central UniversitiesSouth-Central Minzu UniversitySouth-Central Minzu University

2197217022072184CZY13005CZT20010

2024

10.13563/j.cnki.jmolsci.2023.14.005

分子科学学报
中国化学会

分子科学学报

CSTPCD
影响因子：0.434
ISSN：1000-9035
年,卷(期)：2024.40(1)
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