Ruthenium-doped metal-organic frameworks for green hydrogen generation on a glassy carbon electrode by enhanced electrochemical water splitting

Abstract

To improve the effectiveness and stability of the hydrogen evolution reaction (HER) process, Ru-loaded MIL-101 (Fe) metal-organic frameworks (MOFs) were grown as a coating on a glassy carbon electrode. The synthesized composites were analyzed by spectroscopic and microscopic tools as well as elemental analysis and isotherm studies. The two catalysts of Ru-MIL-101 (Cr) and Ru-MIL-101 (Fe) MOFs were designed to enhance the stability and efficiency of the HER. The incorporation of Ru into MIL-101 (Fe) resulted in a twofold increase in the catalytic efficiency for splitting water into hydrogen gas compared to that of pristine MIL-101. Electrochemical impedance spectroscopy (EIS), cycling voltammetry (CV), linear sweep voltammetry (LSV), and Tafel plots were used to compare the hydrogen-producing catalytic performance in water splitting. The electrochemical double-layer capacitances (Cdl) for the variations of HER performance of MIL-101 (Fe) with a Ru percentage of 30% towards HER showed a low potential of 154 mV at 10 mA cm-2 in 1 M H2SO4, along with improved reaction kinetics for a Ru with a less percentage of 10% as evidenced by the Tafel slope analysis. In addition, Ru 20% MIL-101 (Fe) exhibited high stability during repetitive potential cycling (5000 cycles).