Interference effect of nitrogen-doped CQDs on tailoring nanostructure of CoMoP for improving high-effective water splitting

The construction of bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is significant for developing water splitting technology. The carbon-based non-noble metal catalysts could be regarded as a preferred alternative to Pt-based materials in water splitting, but very rarely Pt-like activity has been obtained by non-noble metal catalysts. Herein, NCQDs/CoMoP/NF bifunctional catalysts were designed and synthesized by the coupling relationships between N-doped carbon quantum dots (NCQDs) and metal ions . The abundant functional groups on the surfaces of CQDs can effectively coordinate with metal ions with empty d orbitals to generate the stable composites. Meanwhile, the formation of metal nanoparticles can be restricted by the introduction of CQDs to form smaller crystals with stable nanostructures , thereby preventing the agglomeration and further growth of metal nanoparticles . The NCQDs-100/CoMoP/NF electrode shows a low overpotential of 65 mV (10 mA cm −2 ) for HER and 370 mV (100 mA cm −2 ) for OER in a 1.0 M KOH system. Furthermore, the constructed NCQDs-100/CoMoP/NF couple can reveal a small cell voltage of 1.75 V to reach the large current density of 50 mA cm −2 .