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In this paper, the reaction mechanism for N 2 O with CO on the surface of Ni 5 cluster was investigated by the B3LYP method of density functional theory (DFT). Ni atom of various species was calculated using B3LYP/ LANL2DZ basis set, and C, N, O atoms at B3LYP/6-31G ∗ level. In the temperature range of 100–1000 K, the statistical thermodynamics and Eyring transition state theory with Winger correction were used to study the kinetic characters of reaction. The calculation results indicated that the reaction of N 2 O with CO on Ni 5 cluster had two major reacting processes: (1) O atom first dissociated from N 2 O on Ni 5 cluster, and then reacted with CO on Ni 5 and (2) on the surface of Ni 5 catalyst, O atom of N 2 O direct interacted with C atom of CO, resulting into the dissociation of N 2 O and the form of CO 2 . The direct O extraction channel was the main channel due to its low potential energy and high rate constant. [ABSTRACT FROM AUTHOR]

The mechanism of Ti 2 + catalyzed cyclohexane dehydrogenation had been studied at the B3LYP level of density functional theory (DFT). The first molecular dehydrogenation products were [Ti 2 (C 6 H 10 )] + and H 2 , this process proceeded quite facile. After the elimination of the first molecular H 2 , there were two competitive mechanisms, one was the same-face dehydrogenation, the other was the H/D scrambling mechanism. The activation barrier for rate determining step of same-face dehydrogenation was 15.34 kcal/mol, while 14.49 kcal/mol for the different-face dehydrogenation which was more favorable than same-face one. Whole reaction proceeded in mixed potential energy surfaces (PESs) and the reaction products were mixture of the doublet and the quartet states. We calculated also all minimum energy crossing points (MECPs) between potential energy surfaces and analyzed bonding orbital of MECPs. [ABSTRACT FROM AUTHOR]

• The mechanism of HER on Mo-Edge with the unsaturated Mo and S were investigated. • The H 2 evolution reaction mainly occurred on Mo U. • The formation of molybdenum hydride (Mo U -H) was the rate-limiting step. In this paper, the mechanisms of H 2 evolution over the Mo-Edge of 2H-MoS 2 with the unsaturated Mo (Mo U) and S (S U) were investigated by the density functional theory. The calculations indicated that Mo U was a key active site for H 2 evolution. In the process of H 2 evolution, the S U firstly absorbed H atom by the Volmer reaction, which caused the aggregation of electron on Mo U , resulting in the barriers reduction of H transfer and H 2 evolution on Mo U. The formation of molybdenum hydride was the rate-limiting step. Compared to Mo-edge in 2H-MoS 2 , the barrier of key step for H 2 evolution on Mo-edge with S U and Mo U decreased obviously. This implied that the removal fractional S from the Mo-edge of 2H-MoS 2 could enhance its H 2 evolution activity and the electron trapping ability of active site for H 2 evolution by the Volmer-Heyrovsky reaction might affect its activity. [ABSTRACT FROM AUTHOR]

In this paper, the mechanisms of H 2 evolution on Pt 6 , Pt 5 Sn 5 , and Pt 3 Sn 6 clusters were respectively investigated by the B3LYP method of density functional theory (DFT). The B3LYP functional with non-local dispersion corrections (B3LYP-D3) method were performed to investigate the adsorption of H and H + on clusters. The calculation results indicated that the adsorption energy of H on Pt reduced due to the interaction of Sn and Pt, which promoted H desorption from Pt to form H 2 . Meanwhile, Sn atom of Pt 5 Sn 5 and Pt 3 Sn 6 clusters had strong interaction with H + due to the existence of Pt, which was benefit for the reduction of H + on Sn atom. As a consequence, Pt 5 Sn 5 and Pt 3 Sn 6 showed lower potential barrier and higher activities than Pt for H 2 evolution. The potential barriers of H 2 formation over Pt 3 Sn 6 clusters was only 11.1% of that over Pt cluster. [ABSTRACT FROM AUTHOR]