Boosting the OER/ORR/HER activity of Ru-doped Ni/Co oxides heterostructure

The development of cheap and efficient OER/ORR/HER electrocatalysts is important to promote green energy conversion and storage technologies. Experimental results show that the synergistic effect of Ru doping and NiO/Co3O4 heterostructure can significantly improve the catalytic activity. The existence of NiO/Co3O4 heterostructure, the appropriate proportion of Ru (only 2%) and the proper electronic energy state tuning are determined by electronic detection and elemental analysis, which enhanced the activation energy, electrical conductivity and electrochemical active surface area of the catalyst. Thus, the Ru-doped NiO/Co3O4 heterostructure exhibits superior OER/ORR/HER performance, reaching 100 mA cm−2 in alkaline electrolytes at only 138 mV (HER) and 269 mV (OER) overpotential, and a high half-wave potential of 0.88 V (ORR). The water-splitting device assembled by the catalyst can operate stably for a long time (>40 h), better than Pt/C and RuO2 at high current densities.