LAUSR

Rational design of efficient bifunctional electrocatalysts is highly imperative but still a challenge for overall water splitting. Herein, we construct novel self-supported Co3N nanowire arrays with different Mo doping contents by the hydrothermal and nitridation processes, serving as bifunctional electrocatalysts for overall water splitting. The optimal Co3N-Mo0.2/NF electrode delivers the low overpotential of 97 mV at the current density of 50 mA cm-2 as well as high stability for HER. DFT calculations prove that Mo doping can effectively modulate the electronic structure and surface adsorption energies of H2O and hydrogen intermediates of Co3N, leading to improved reaction kinetics with high catalytic activity. Furthermore, the modification of FeOOH species on the surface of Co3N-Mo0.2/NF can further improve the OER performance benefiting from the synergistic effect of dual Co-Fe catalytic centers. As a result, the Co3N-Mo0.2@FeOOH/NF catalysts display outstanding OER catalytic performance with low overpotentials of 250 mV at 50 mA cm-2. The constructed Co3N-Mo0.2/NF||Co3N-Mo0.2@FeOOH/NF water electrolyzer exhibits a small voltage of 1.48 V to achieve a high current density of 50 mA cm-2 at 80 oC, which is superior to most of the reported electrocatalysts. This work provides a new approach to developing robust electrode materials for electrocatalytic water splitting.