摘要
Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separability of iron-based carriers require further enhancement.This study investigates the effect of the concentration of Mn doping on reactivity,elastic properties and magnetic properties based on density functional theory(DFT)calculations.Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy(E_(vac))from 2.33 to 0.87 eV.However,Mn doping introduces HV/EV Ms lattice distortions that deteriorate elastic properties,thereby reducing wear resistance,as evidenced by a 54.54%decrease in the hardness-to-Young's modulus ratio(H_(v)/E_(v))forα-Fe_(2)O_(3)and an 83.33%reduction for Fe_(3)O_(4).Furthermore,Mn doping also modifies magnetic properties.The maximum of saturation magnetization(M_(s))of Fe_(3)O_(4)reaches 121.02 emu/g at 33.33%Mn doping concentration.Finally,systematic evaluation identifies 33.33%as the optimal Mn doping concentration,achieving a balance in enhanced reactivity,superior magnetic performance,and retained elastic stability.
载氧体在化学链燃烧(CLC)过程中起着关键作用。铁基载氧体因其储量丰富且对环境友好而备受关注,但其反应活性和分离性能仍需进一步提升。本研究基于密度泛函理论(DFT)计算,研究了Mn掺杂浓度对α-Fe_(2)O_(3)反应活性、弹性性能和磁性能的影响规律。结果表明,Mn掺杂通过将氧空位形成能(Evac)从2.33 eV降低至0.87 eV,显著提升了材料反应活性;但会引发晶格畸变导致弹性性能劣化,使耐磨性下降,具体表现为α-Fe_(2)O_(3)的硬度-杨氏模量比(HV/EV)降低54.54%,Fe_(3)O_(4)降低83.33%;同时Mn掺杂会改变材料磁性能,当掺杂浓度为33.33%时,Fe3O4的饱和磁化强度(Ms)达到最大值121.02 emu/g。通过综合评估,最终确定33.33%为最佳Mn掺杂浓度,可在提升反应活性的同时兼顾磁性能优化与弹性稳定性。
出处
《燃料化学学报(中英文)》
北大核心
2026年第2期140-152,共13页
Journal of Fuel Chemistry and Technology
基金
Supported by National Natural Science Foundation of China(50976032,51776070)。
