Controllable boosting activity on Co4N by Fe substitution for oxygen evolution reaction and efficient 5-hydroxymethylfurfural oxidation

The design of transition metal nitrides with excellent oxygen evolution reaction and 5-hydroxymethylfurfural oxidation reaction (HMFOR) is of great significance to achieve the goal of "carbon peaking and carbon neutrality". Herein, Fe-doped bimetallic nitride FexCo1-x)4N was prepared by a simple electron regulation strategy. The introduction of Fe changes the electronic structure of Co and optimizes the adsorption energies of *OH, reduces the potential barrier for the generation of *OOH as a potential-determining step and thus increases the intrinsic OER activity of Co4N. In addition, Fe substitution of some of the Co atoms gives (FexCo1-x)4N a higher electrochemical active surface area, which accelerates the electron transfer efficiency and improves the electrical conductivity. The overpotential for (FexCo1-x)4N-0.9 to reach a current density of 10 mA cm−2 in 1 M KOH is only 271 mV. When in 1 M KOH + 50 mM HMF condition, (FexCo1-x)4N requires only 1.37 V to reach a current density of 10 mA cm−2. This work provides practical guidance for developing bifunctional transition metal electrocatalysts with excellent OER and HMFOR activity.