Efficient water oxidation through strongly coupled graphitic C3N4 coated cobalt hydroxide nanowires

The development of low cost and durable electrocatalysts for the oxygen evolution reaction (OER) for water splitting remains a great challenge. Here, we developed strongly coupled hybrid nanowires (NWs) of anion (Cl- and CO-) doped cobalt hydroxide coated with nanosheets of graphitic carbon nitride (Co(OH)(2)@gC(3)N(4)) through an in situ hydrothermal method. With 5% g-C3N4 added in the synthesis, we obtained perfectly coated Co(OH) 2 by g-C3N4 nanosheets with an overall diameter of similar to 110 nm and a coating layer of similar to 10 nm. The structural and compositional analyses confirm the strong interaction between gC(3)N(4) and Co(OH)(2) that makes the hybrid highly effective for the OER. As a result Co(OH)(2)@g-C3N4 NWs exhibit an excellent over-potential of 0.32 V at 10 mA cm(-2) as well as extraordinary stability, which are better than those of the state-of-the-art noble metals (IrO2 and RuO2) and most reported Co- and C3N4-based electrocatalysts although both Co(OH)(2) and g-C3N4 separately display very fair performance. Furthermore, a combination of Co(OH)(2)@ g-C3N4 and Pt/C delivers a current density of 80 mA cm(-2) at 1.9 V for overall water splitting.