Synchronously integration of Co, Fe dual-metal doping in Ru@C and CDs for boosted water splitting performances in alkaline media

• CoFeRu@C and CoFe-CDs with different electrocatalytic functions were simultaneously synthesized within one-pot hydrothermal reactor. • Synergistic effect of Co, Fe co-doping in CDs and Ru@C effectively improved the charge transfer and electrocatalytic activities . • CoFeRu@C exhibited the lowest HER overpotential of 4 mV in 1 M KOH among all the reported noble- and non-noble metal-based HER electrocatalysts . • Based on CoFe-CDs/CoFeRu@C system only 1.59 V was needed to achieve 10 mA cm -2 for electrochemical overall water-splitting in alkaline media. The unsatisfactory performances and complicated synthesis procedures greatly impeded the large-scale industrial applications of various electrocatalysts . Herein, two different functional electrocatalysts were simultaneously synthesized within one-pot reactor through hydrothermal method. The Co, Fe co-doped carbon dots (CoFe-CDs) with electrocatalytic oxygen evolution reaction (OER) activities and carbon-supported Co, Fe co-doped Ru networks (CoFeRu@C) with hydrogen evolution reaction (HER) activities, were directly obtained from the supernatant and the precipitation, respectively. Benefiting from the synergistic effect of dual-metal doping, the CoFeRu@C exhibited an extremely low overpotential of 4 mV for HER in 1 M KOH electrolyte, which was the lowest value among the previously reported electrocatalysts, and the CoFe-CDs showed excellent OER performance with an overpotential of 320 mV. Moreover, only 1.59 V was needed to achieve 10 mA cm −2 for overall water-splitting. This work provided an innovative approach for simply creating diverse electrocatalysts and effectively regulating the catalytic activities by introducing multi-metal dopants.