Hydrogen evolution reaction catalyzed by Co-based metal-organic frameworks and their derivatives
Natalia Łukasik, Daria Roda, Maria Alaide de Oliveira, Bráulio Silva Barros, Joanna Kulesza, Marcin Łapiński, Hanna Świątek, Anna Ilnicka, Tomasz Klimczuk, Mariusz Szkoda
Abstract
In this study, Co-bearing Metal-Organic Frameworks (MOFs) are grown via a facile solvothermal process on the surface of two kinds of conductive substrates – titanium dioxide nanotubes (TiO 2 NT) and fluorine-doped tin oxide (FTO) glass and tested as electrodes in the electrochemical hydrogen evolution reaction (HER). The materials derived from three organic linkers - terephthalic acid (Co-BDC), 2-aminoterephthalic acid (Co-BDCNH 2 ), and trimesic acid (Co-BTC) are characterized by FTIR, Raman, XRD, SEM-EDS, BET, and XPS. Among the layers on FTO without post-synthesis treatment, Co-BTC shows the highest activity (overpotential of HER 1.72 V vs. Ag/AgCl/KCl). The effects of substrate change on TiO 2 NT and annealing of Co-BTC layers in air and argon on their electrocatalytic properties are also studied. Using TiO 2 nanotubes as a substrate and annealing the material in air results in a reduction of the hydrogen evolution overpotential to 1.44 V vs. Ag/AgCl/KCl and a significant reduction in the exchange current density. • Co-based MOFs were successfully fabricated on FTO and TiO 2 NT. • Electrochemical activity depended more on organic linker than substrate type. • Annealing of Co-BTC materials improves catalytic activity in HER.