| As we all know, with the gradually exhausted non-renewable energy resource(coal, oil and natural gas, and so on), researching, exploiting and using renewable energy have become hot research topics. Hydrogen has become one of ideal energy carriers because of its efficiency,abundance and environmental friendline. In addition, one of the most difficult problems, which restrict the rapid development of the hydrogen economic development, is to find very superior hydrogen storage materials. Of course, the superior hydrogen storage materials must satisfy the conditions of high hydrogen content, good renewable properties and the high efficiency of dehydrogenation. In many hydrogen storage materials, ammonia borane(NH3BH3, AB) has been considered as an excellent hydrogen storage material because of these conditions. But its catalyst dehydrogenation products, dehydrogenation styles and microscopic mechanism are different under the existences of different catalytics. Herein, we predicted the catalyst dehydrogenation products,dehydrogenation styles and microscopic mechanism of NH3BH3 molecular by the catalysts of transition metal(TM) clusters through theoretical simulations and calculations. Main contents are as follows.Using the generalized gradient approximation and the exchange correlation potential BPW91(GGA-BPW91) under the framework of density functional theory(DFT), the various possible configurations of TM clusters(Cu2, Fe2, FeCu, Fe12Cu), water(H2O) and AB molecules and TM clusters absorbing H2 O or AB moleculars have been optimized. Furthermore, applying the computational method, we have performed a systemically research various on dehydrogenation routes of the most stable configurations of an AB molecular adsorbed on transition metal clusters,giving the most favorable dehydrogenation routes. The concrete research contents are listed as followings:(1) First of all, Gauss View and Materials Studio software are used to build transition metal cluster structures, small molecular structures and various possible structures of TM clusters absorbing H2 O or AB moleculars.(2) Secondly, we have utilized Gaussian 03/09 to optimize these built structures. Exploiting Gauss View and Multiwfn software, the bond lengthes, the atomic charge distributions, HOMO outline, LUMO outline, total energy, zero correction energy, enthalpy,and adsorption energy of transition metal clusters absorbing a H2 O molecular or an AB molecular were analyzed. Our study results suggest that the adsorption and interaction energies of an AB molecular absorbed on TM clusters were larger than those of a H2 O molecular, and the changes of the bond lengthes in an AB molecular after being adsorbed are more obvious than that of a H2 O molecular, respectively.(3) In dehydrogenation routes of NH3BH3 by catalyst of TM clusters, the corresponding intermediate configurations have been designed by analysing the HOMO, bond lengthes and charge distributions of the corresponding structures. Whereafter, the intermediate configurations are optimized by 03/09 Gaussian. We have given reliable transition state structures,completing the study of the dehydrogenation routes of the systems between an AB and TM clusters.Our results shown that, in the AB dehydrogenation reaction by the catalysts of TM clusters, the formations of corresponding dihydrogen compounds involves the stepwise transfering of H(N) and H(B) atoms from an AB part to a TM atom of clusters, and then the polymerize hydrogen molecule is released from these systems. A novel dehydrogenation style of AB molecular has been given,namely, the dehydrogenation style of AB molecular is also we recommended. |
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