金属卟啉配合物催化MgH_(2)脱氢反应的理论研究  

Theoretical studies on MgH2 dehydrogenation reaction catalyzed by metalloporphrin complexes

作　　者：唐文艳 张睿煜 胡帅旗 毕奇陶 吴文鹏[1] TANG Wenyan;ZHANG Ruiyu;HU Shuaiqi;BI Qitao;WU Wenpeng(Henan Key Laboratory of Protection and Safety Energy Storage of Light Metal Materials,College of Chemistry and Molecular Sciences,Henan University,Kaifeng 475004,Henan,China)

机构地区：[1]河南大学化学与分子科学学院,河南省轻金属材料防护与安全储能重点实验室,河南开封475004

出　　处：《化学研究》2024年第4期328-335,共8页Chemical Research

基　　金：国家自然科学基金(21703053)。

摘　　要：氢化镁(MgH_(2))具有较高的储氢密度和环境友好性,是一种具有潜在应用价值的固态储氢材料。但是,其脱氢热力学稳定仍是约束实际应用的障碍。为了解决这一问题,本文基于密度泛函理论(DFT)分析了六种过渡金属卟啉配合物(TMTPP,TM=Mn、Fe、Co、Ni、Cu、Zn)作为催化剂对MgH2储氢性能的影响。结果发现,通过TMTPP的催化作用,MgH_(2)脱氢的生成焓降低了0.56~1.12 eV,进而分析了MgH_(2)/TMTPP体系的差分电荷密度、态密度和晶体轨道哈密顿布居等。结果显示,MgH_(2)/CoTPP体系的生成焓最低,主要是因为CoTPP的添加影响H的电子特性,H原子上的电荷向CoTPP侧转移,导致Mg-H键变长、键强度减弱,使MgH_(2)失稳。同时发现Mg-H键长与脱氢生成焓相对应,因此可将Mg-H键长作为一个反映脱氢性能的有效描述符。Magnesium hydride(MgH2)is a solid-state hydrogen storage material with potential application due to its high hydrogen storage density and environmental friendliness.But its thermodynamic stability of dehydrogenation is still an obstacle to practical application.In order to solve this problem,the effects of six transition metal porphyrin complexes(TMTPP,TM=Mn,Fe,Co,Ni,Cu,Zn)on the hydrogen storage performance of MgH2 were analyzed based on density functional theory(DFT).The results show that the enthalpy of MgH2 dehydrogenation can be reduced by 0.56~1.12 eV because of the catalysis of TMTPP,and the charge density differences,density of states and crystal orbital Hamiltonian population of the MgH2/TMTPP system were analyzed.The results show that the MgH2/CoTPP system has the lowest enthalpy of formation,mainly because of the addition of CoTPP affects the electronic properties of H,and the charge on the H atom is transferred to the CoTPP side,resulting in the lengthening of the Mg-H bond and the weakening of the bond strength,as well as the instability of MgH2.Moreover,it is found that the Mg-H bond length corresponds to the enthalpy of dehydrogenation,so the Mg-H bond length can be used as a valid descriptor to reflect the dehydrogenation performance.

关 键 词：密度泛函理论 MgH_(2) 金属卟啉配合物 脱氢 

分 类 号：O641[理学—物理化学]