In Situ Generation of Active Molybdenum Octahedral Clusters for Photocatalytic Hydrogen Production from Water.
The photocatalytic hydrogen evolution reaction (HER) from water under homogeneous and heterogeneous conditions is explored for the {Mo6 Br(i) 8 }(4+) cluster core based unit starting from (TBA)2 [Mo6 Br(i) 8 F(a) 6 ] (TBA=tetra-n-butylammonium; "i" and "a" refer to the face-capping inner and terminal apical ligand, respectively). The catalytic activity of {Mo6 Br(i) 8 }(4+) is enhanced by the in situ generation of [Mo6 Br(i) 8 F(a) 5 (OH)(a) ](2-) , [Mo6 Br(i) 8 F(a) 3 (OH)(a) 3 ](2-) , and [Mo6 Br(i) 8 (OH)(a) 6 ](2-) , which are identified by ESIMS, luminescence, and NMR techniques. Full substitution of F(-) by OH(-) leads to the formation of (H3 O)2 [Mo6 Br(i) 8 (OH)(a) 6 ]⋅10 H2 O; its structure was determined by single-crystal XRD. The immobilization of the active {Mo6 Br(i) 8 }(4+) onto graphene oxide (GO) surfaces enhances its stability under catalytic conditions. The catalytic activity of the resulting (TBA)2 Mo6 Br(i) 8 @GO material is improved with respect to GO, but is reduced compared to the activity under homogeneous conditions because of changes in the GO semiconducting properties as well as lower activity and/or accessibility of the anchored cluster.
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, España. mfeliz@itq.upv.es.
Marta
0000-0002-4429-0551
M
Feliz
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, España.
Marta
M
Puche
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, España.
Pedro
P
Atienzar
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, España.
Patricia
P
Concepción
Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes 1, Campus de Beaulieu, 35042, Rennes Cedex, France. stephane.cordier@univ-rennes1.fr.
Stéphane
S
Cordier
Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes 1, Campus de Beaulieu, 35042, Rennes Cedex, France.
Yann
Y
Molard
D064751:Ammonium Compounds / Q000737:chemistry; D002384:Catalysis; D006108:Graphite / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D008982:Molybdenum / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D055668:Photochemical Processes; D014867:Water / Q000737:chemistry*
D064751:Ammonium Compounds; D010087:Oxides; D014867:Water; D006108:Graphite; D006859:Hydrogen; D008982:Molybdenum
cluster; graphene; hydrogen evolution reaction; molybdenum; nanocomposite