Development of high-efficiency alkaline OER electrodes for hybrid acid-alkali electrolytic H2 generation

The development of high-efficiency oxygen evolution reaction (OER) electrocatalysts is of great importance for electrolytic H2 generation. In this work, we report in-situ growth of MnCo2O4 nanoneedles and NiFeRu layered double hydroxide (LDH) nanosheets on nickel foam (NF) (MnCo2O4@NiFeRu-LDH/NF) that can function a highly efficient electrode toward electrocatalysis of OER. Such electrode demands an overpotential of as low as 205 mV to reach 10 mA cm-2 in alkaline electrolyte and can run stably over 120-hours continuous operation. A hybrid flow acid/alkali electrolyzer is set up by using the Pt/C as the acidic cathode coupling with the MnCo2O4@NiFeRu-LDH/NF as the alkaline anode, which only requires an applied voltage of 0.59 V and 0.94 V to attain an electrolytic current density of 10 mA cm-2 and 100 mA cm-2, respectively. The present work could push forward the further development of the electricity-saving electrolytic technique for H2 generation.