Supporting material as controlling element for replacement and reduction of platinum-group metals in acidic water electrolysis

In this work, a comprehensive investigation was conducted into the synthesis of innovative, cost-effective catalytic materials for water electrolysis under acidic conditions using a supported catalyst approach. The reductive treatment of commercially available conductive carbon facilitated the development of a nanosized orthorhombic iron phosphide cathode catalyst for the hydrogen evolution reaction (HER), yielding a current density of 10 mA/cm 2 at an overpotential of 100 mV for at least 60 h. In addition, an ultrasmall tetragonal iridium oxide anode catalyst supported on commercially available antimony tin oxide was synthesized which demonstrated a current density of 10 mA/cm 2 at an overpotential of 280 mV, while sustaining oxygen evolution reaction (OER) performance for 35 h. The overall water splitting (OWS) over optimized cathode and anode catalysts was further investigated, achieving an overpotential of 280 mV at a current density of 10 mA/cm 2 , which exhibited remarkable stability over 100 h of OWS testing. Most notably, the OWS performance of the newly synthesized catalytic materials was found to closely approach that of the benchmark, despite the significantly reduced platinum-group metals (PGM) loading. Hence, supported catalysts offer a straightforward yet effective approach of producing cost-effective materials for applications in proton exchange membrane water electrolysis.