原子簇NiFeB2的结构及催化性能

利用DFT(密度泛函理论)方法,对原子簇NiFeB2的10余种可能构型在单重态下进行优化计算,分析比较了优化结果的能量、成键、电荷分布情况及不同构型的催化性能.结果表明:原子簇NiFeB2以B-B键较长的三角锥形1构型最稳定,是原子簇NiFeB2最有可能存在的构型,B-B在Ni-Fe异侧的平面四边形2构型次之;Ni-B,Fe-B原子间有强烈的成键作用且Fe-B间作用力比Ni-B间作用力大;各构型中电子由B转向Ni,Fe;在形成原子簇NiFeB2的过程中Fe,B原子的所有轨道均参与成键,Ni原子的4p,4s在其成键中起主要作用;除了B-B键较短的三角锥形3构型外的其它构型中Fe原子的催化活性高于Ni原子,B-B键较短的三角锥形3构型和直线型4构型可能具有较好的催化性能;在催化加氮和加氢上直线型4构型具有较好的催化活性.

Study on structure and catalytic performance of NiFeB2 atom clusters

The energy,bonding,charge distribution and catalytic performance of various optimization configurations of atomic cluster NiFeB₂ are analyzed and compared,the optimization calculation of its more than 10 possible configurations in singlet is made by using DFT method（density functional theory）. The results show that No.1 triangular pyramid of atom cluster NiFeB₂ with a longer bond B-B,is the most steady and most likely configuration.No.2 square planar configuration with bond B-B on the opposite side of the bond Ni-Fe follows by the former in stability.There is a stronger interaction between Fe-B than Ni-B.The electrons of each configuration shift from B to Ni and Fe.In the process of formation of clusters NiFeB₂,all tracks of Fe and B atoms are involved in the bonding,and 4p and 4s tracks of Ni atoms play a major role in the bonding.In addition to the configuration of No.3 triangular pyramid with a shorter bond B-B,the catalytic activity of Fe atoms is stronger than Ni atoms,No.3 triangular pyramid with a shorter bond B-B and the No.4 linear configuration may have a better catalytic performance.No.4 linear configuration plays a good catalytic activity in the catalytic nitrogen and hydrogenation.