摘要
本文研究了氧化石墨烯负载Pt单原子(Pti/Gr-O)催化硼胺烷(NH3BH3)全水解反应机理,即一分子的NH3BH3生成三分子的氢气(H2)的过程.在水解路径中,首先吸附的硼胺烷连续断裂两个B-H键生成第一分子的H2.接着,一个H2O分子与*BHNH3基团(*表示吸附态)反应生成*BH(H2O)NH3,其中伸长的O-H键断裂后形成*BH(OH)NH3.然后,第二个H2O与*BH(OH)NH3反应生成*BH(OH)(H2O)NH3,在指向Pti/Gr-O表面的O-H断裂后,生成BH(OH)2NH3并脱附到水溶液中.两个水分子脱氢产生的两个H原子脱附生成第二个H2分子,且Pti/Gr-O催化剂恢复.脱附后的BH(OH)2NH3在水溶液中水解生成第三个H2分子.纵观整个水解反应,H2O分子和*BHNH3基团的结合是反应速控步,其反应能垒是16.1kcal/mol.因此,Pti/Gr-O有希望成为室温催化NH3BH3全水解催化剂.
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(Pt1/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 Pt1/Gr-O results in the desorption of BH(OH)2NH3.The second hydrogen molecule is produced from two hydrogen atoms coming from two H2O molecules and Pt1/Gr-O is recovered after the releasing of hydrogen molecule.The third hydrogen molecule is generated by the further hydrolysis of BH(OH)2NH3 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,Pt1/Gr-O is suggested to be a promising catalyst for hydrolysis of NH3BH3 at room temperature.
作者
吴红
罗其全
张瑞奇
张文华
杨金龙
Hong Wu;Qi-quan Luo;Rui-qi Zhang;Wen-hua Zhang;Jin-long Yang(Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Tech-nology of China,Hefei 230026,China;Key Laboratory of Materials for Energy Conversion,Chinese Academy of Sciences,University of Science and Technology of China,Hefei 230026,China;Synergetic Innovation Center of Quantum Information Quantum Physics,University of Science and Technology of China,Hefei 230026,China;Department of Applied Mathematics,School of Physics and Engineering,Australian National Uni-versity,Canberra,ACT 2600,Australia)
基金
supported by the National Natural Science Foundation of China (No.21473167 and No.21688102)
the National Key Research and Development Program of China (No.2016YFA0200604)
the Fundamental Research Funds for the Central Universities (WK3430000005,WK2340000065)
the China Scholarship Council (CSC) (No.201706345015)
关键词
密度泛函理论
单原子催化
PT
氧化石墨烯
硼胺烷水解
Density functional theory
Single atom catalysis
Platinum
Oxidized graphene
Ammonia borane hydrolysis