An Fe_(2)catalyst combined with the vicinal nonmetallic sites may break the Bronsted-Evans-Polanyi limitation and lead to a more efficient ammonia synthesis than previously reported.Our theoretical calculations show t...An Fe_(2)catalyst combined with the vicinal nonmetallic sites may break the Bronsted-Evans-Polanyi limitation and lead to a more efficient ammonia synthesis than previously reported.Our theoretical calculations show that the Fe_(2)catalyst supported on graphitic carbon nitride(Fe_(2)/mpg-C_(3)N_(4))strongly favors hydrogenation of^(*)N_(2)to form^(*)NHNH_(2)species,which leads to low energy barriers for N-H formation(0.47 eV)and N-N dissociation(0.50 eV).In addition,B-N Lewis pairs constructed on the mpg-C_(3)N_(4)serve as nonmetallic sites that enable heterolysis of the H-H bond to overcome the relatively high energy barrier of hydrogen transfer.Through a comprehensive study of Fen/mpg-C_(3)N_(4)(n=2,3,4)and Fe(211)catalysts,we conclude that synergistic Fe_(2)catalyst shows a significant advantage due to its high spin polarization and thus can avoid harsh reaction conditions for the thermal conversion of N_(2)to NH_(3).展开更多
基金the National Natural Science Foundation of China(21890722,21950410519,21712109)the Natural Science Foundation of Tianjin Municipality(19JCJQJC62300,18JCYBJC21400)+2 种基金Tianjin Research Innovation Project for Postgraduate Students(2019YJSB081)the Frontiers Science Center for New Organic Matter[Nankai University(No.63181206)]the Supercomputing Centre of Nankai University(NKSC)for generous financial support。
文摘An Fe_(2)catalyst combined with the vicinal nonmetallic sites may break the Bronsted-Evans-Polanyi limitation and lead to a more efficient ammonia synthesis than previously reported.Our theoretical calculations show that the Fe_(2)catalyst supported on graphitic carbon nitride(Fe_(2)/mpg-C_(3)N_(4))strongly favors hydrogenation of^(*)N_(2)to form^(*)NHNH_(2)species,which leads to low energy barriers for N-H formation(0.47 eV)and N-N dissociation(0.50 eV).In addition,B-N Lewis pairs constructed on the mpg-C_(3)N_(4)serve as nonmetallic sites that enable heterolysis of the H-H bond to overcome the relatively high energy barrier of hydrogen transfer.Through a comprehensive study of Fen/mpg-C_(3)N_(4)(n=2,3,4)and Fe(211)catalysts,we conclude that synergistic Fe_(2)catalyst shows a significant advantage due to its high spin polarization and thus can avoid harsh reaction conditions for the thermal conversion of N_(2)to NH_(3).
