Hydrophilic functionalization of rhodium metallene for saving-energy hydrogen production and sulfur recovery

The use of thermodynamically more favorable sulfion oxidation reaction (SOR) to replace sluggish oxygen evolution reaction is an effective method for energy-saving production of hydrogen. Herein, we propose the synthesis of organic–inorganic hybrid through the modification of 1-hydroxyethylidene-1,1-diphosphonic acid on Rh metallene (HEDP-Rh metallene) as a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and SOR. The modification of hydrophilic HEDP can effectively promote the water adsorption, thereby accelerating the mass/electron transfer at the interface. The HEDP-Rh metallene requires low overpotentials of 30 mV at 10 mA cm −2 for HER and 0.538 V at 100 mA cm −2 for SOR. In HER-SOR coupled reaction, HEDP-Rh metallene drives the current density of 100 mA cm −2 at 1.08 V for concurrent production of hydrogen and sulfur, highlighting energy-efficient hydrogen production and sulfur recycle.