Hydrolysis of Ammonia Borane on a Single Pt Atom Supported by N-Doped Graphene.

Abstract

The hydrolysis of ammonia borane (NH3BH3 or AB) at room temperature is a promising method to produce hydrogen, but the complete reaction mechanism is still less investigated. Herein, the full hydrolysis process of the AB molecule on single Pt atom coordinated by two carbon atoms and one nitrogen atom (Pt1-C2N1) on nitrogen doped graphene is investigated using the density functional theory (DFT) method. Our results demonstrate that the rate-limiting step is the formation of *BH2NH3 by breaking the first B-H bond in AB with an energy barrier of 0.68 eV, implying that Pt1-C2N1 is a potential room-temperature catalyst for the full hydrolysis of AB. In addition, 27 more types of M1-C2N1 (M represents transiton metal atom) and Pt1 supported on nitrogen-doped graphene with different local coordination environments (Pt1-CxNy, x and y are the number of carbon and nitrogen atoms that coordinated with the platinum atom) are considered to screen out potential single-atom catalysts for AB hydrolysis. The screening results further show that Pt1-C1N2 is another potential catalyst for AB hydrolysis. In particular, two hydrogen atoms precovered on Pt1-C1N2, resulting in a lower energy barrier for the rate-limiting step than that on Pt1-C2N1. This study provides a prototype of Pt1-C1N2 and Pt1-C2N1 for catalytic full hydrolysis of AB at room temperature.