CuO与负载间相互作用的密度泛函理论  

Density Functional Theory Calculation for CuO-Support Interactions in Cu-Based Oxygen Carriers

作　　者：桂进发 张永亮[1] 赵海波[1] Gui Jinfa;Zhang Yongliang;Zhao Haibo(State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《燃烧科学与技术》2017年第2期173-179,共7页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51522603)

摘　　要：通过密度泛函理论(DFT)模拟了不同负载对Cu基氧载体反应性能和抗烧结性能的影响.首先通过DFT模拟计算得出了CuO纳米团簇在4种不同负载(TiO_2、ZrO_2、CuAl_2O_4和MgAl_2O_4)上的吸附能分别为-2.96eV、-5.14eV、-4.25eV和-5.42eV,其中TiO_2的吸附能最低,不利于氧载体颗粒的抗烧结性,但CuO在ZrO_2、CuAl_2O_4和Mg Al2O4上的高吸附能有助于抑制氧载体的烧结.通过计算不同负载下团簇释氧过程的能量势垒来比较负载对氧载体释氧性能的影响.结果表明,氧气分子从表面的脱附过程是整个释氧过程的速控步骤.不同负载(TiO_2、ZrO_2、CuAl_2O_4和MgAl_2O_4)下CuO纳米团簇总的释氧能量势垒分别为3.45eV、3.33eV、3.28eV和3.41eV,其中负载于CuAl_2O_4的CuO释氧能量势垒最低,反应活性最高.Periodical density functional theory(DFT)calculations were conducted to gain an insight into the effectsof different supports(TiO2,ZrO2,CuAl2O4and MgAl2O4)on the Cu-based oxygen carrier performance in termsof reactivity and resistance to sintering.First,the adsorption energies of CuO nanocluster on the four supportswere calculated and they were-2.96,eV,-5.14,eV,-4.25,eV and-5.42,eV,respectively.The adsorption energyof CuO nanocluster on TiO2is the lowest,which is not beneficial to resistance to sintering of oxygen carrier particles.However,the high stability of CuO nanocluster on ZrO2,CuAl2O4and MgAl2O4helps to suppress the tendencytowards sintering.Then,the energy barriers of oxygen release process were examined to evaluate the effectof support on oxygen carrier decomposition reactivity.Results showed that the desorption of O2molecular from theparticle surface was the rate-determining step for all the supported CuO oxygen carriers.The O2desorption energybarriers were3.45,eV(with the support of TiO2),3.33,eV(with ZrO2),3.28,eV(with CuAl2O4)and3.41,eV(withMgAl2O4),respectively.Among these,CuO/CuAl2O4shows higher reactivity due to relatively low energy barrierorder for O2desorption.

关 键 词：化学链氧解耦燃烧 铜基氧载体 密度泛函理论 抗烧结性 

分 类 号：TK16[动力工程及工程热物理—热能工程]