Single Pt Atoms Supported on Oxidized Graphene as a Promising Catalyst for Hydrolysis of Ammonia Borane

Based on density functional theory calculations, the full hydrolysis of per NH3BH3 molecule to produce three hydrogen molecules on single Pt atoms supported on oxidized graphene (Pt-1/Gr-O) is investigated. It is suggested that the first hydrogen molecule is produced by the combination of two hydrogen atoms from two successive B-H bonds breaking. Then one H2O molecule attacks the left *BHNH3 group (*represents adsorbed state) to form *BH(H2O)NH3 and the elongated O-H bond is easily broken to produce *BH(OH)NH3. The second H2O molecule attacks *BH(OH)NH3 to form *BH(OH)(H2O)NH3 and the breaking of O-H bond pointing to the plane of Pt-1/Gr-O results in the desorption of BH(OH)(2)NH3. The second hydrogen molecule is produced from two hydrogen atoms coming from two H2O molecules and Pt-1/Gr-O is recovered after the releasing of hydrogen molecule. The third hydrogen molecule is generated by the further hydrolysis of BH(OH)(2)NH3 in water solution. The rate-limiting step of the whole process is the combination of one H2O molecule and *BHNH3 with an energy barrier of 16.1 kcal/mol. Thus, Pt-1/Gr-O is suggested to be a promising catalyst for hydrolysis of NH3BH3 at room temperature.