title: Efficient production of hydrogen from formic acid using a covalent triazine framework supported molecular catalyst.
abstract: A heterogeneous molecular catalyst based on Ir(III) Cp* (Cp*=pentamethylcyclopentadienyl) attached to a covalent triazine framework (CTF) is reported. It catalyses the production of hydrogen from formic acid with initial turnover frequencies (TOFs) up to 27,000 h(-1) and turnover numbers (TONs) of more than one million in continuous operation. The CTF support, with a Brunauer-Emmett-Teller (BET) surface area of 1800 m(2)  g(-1), was constructed from an optimal 2:1 ratio of biphenyl and pyridine carbonitrile building blocks. Biphenyl building blocks induce mesoporosity and, therefore, facilitate diffusion of reactants and products whereas free pyridinic sites activate formic acid towards β-hydride elimination at the metal, rendering unprecedented rates in hydrogen production. The catalyst is air stable, produces CO-free hydrogen, and is fully recyclable. Hydrogen production rates of more than 60 mol L(-1)  h(-1) were obtained at high catalyst loadings of 16 wt % Ir, making it attractive towards process intensification.
authors: Catalysis Engineering-ChemE, Delft University of Technology, Julianalaan 136, 2628BL, Delft (The Netherlands).
authors: A V
authors: AV
authors: Bavykina
authors: M G
authors: MG
authors: Goesten
authors: F
authors: F
authors: Kapteijn
authors: M
authors: M
authors: Makkee
authors: J
authors: J
authors: Gascon
mesh_terms: D002384:Catalysis; D005561:Formates / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D014227:Triazines / Q000737:chemistry*
chemical_list: D005561:Formates; D014227:Triazines; C030544:formic acid; D006859:Hydrogen
keywords: covalent triazine frameworks; formic acid; heterogeneous catalysis; hydrogen production; iridium