Metal–organic frameworks based on tetraphenylpyrazine-derived tetracarboxylic acid for electrocatalytic hydrogen evolution reaction and NAC sensing. Issue 3 (13th December 2018) - Wang, Tao
Abstract : Tetraphenylpyrazine-derived tetracarboxylic acid-based new MOFs and their promising applications in the electrocatalytic hydrogen evolution reaction. Abstract : A series of metal–organic frameworks (MOFs), namely {[Cd(H2 TCPP)]·2H2 O} n (1 ), {[Pb2 (TCPP)]} n (2 ), {[La(H2 TCPP)]·3.7H2 O} n (3 ), {[Sr3 (HTCPP)2 ]·6H2 O} n (4 ), {[Ce(HTCPP)]·H2 O} n (5 ) and {[Mn2 (TCPP)]·2.13H2 O} n (6 ), are prepared from 2, 3, 5, 6-(4-carboxyl-tetraphenyl)pyrazine (H 4 TCPP ) with various metal salts under hydrothermal conditions and are well characterized. The structural analysis shows that compound1 presents a 2-fold interpenetrating structure, which exhibits a uninodal 4-c net with a {6 6 }{6·6·6·6(2)·6(2)·6(2)} topology. Compound2 shows a 3-nodal (5, 6, 11)-connected 3D framework with a point symbol of {4 10 }{4 14 ·6}{4 34 ·6 21 }. Compound3 features a (4, 8)-connected 3D network built from a binuclear La cluster with a point symbol of {4 16 ·6 12 }{4 4 ·6 2 }2 . Compound4 demonstrates a 5-nodal (4, 5, 6, 7, 8)-connected network with a {4 10 ·6 5 }{4 12 ·6 9 }{4 18 ·6 10 }{4 6 }{4 7 ·6 3 } topology. Compound5 exhibits a 3D interlocked eight-connected 20-c net with a point symbol of {3 78 ·4 98 ·5 14 }, while compound6 forms a 3, 4, 4, 5, 17-connected net with a point symbol of {4·5 2 }2 {4 32 ·5 6 ·6 84 ·7 4 ·8 10 }{4 5 ·5}{4 6 }{4 8 ·5 2 }. In addition, almost all the MOFs display significant fluorescence quenching behaviors by the addition of various nitro-aromatic compounds (NACs), especially TNP. More importantly, six new MOFs have been further investigated to evaluate their electrocatalytic activities for the hydrogen evolution reaction (HER). The results demonstrate that all the MOFs exhibit improved performance compared to ligandH 4 TCPP for the HER with the lowest onset overpotential of 244 mV and the smallest Tafel slope of 248 mV dec −1, respectively.