Electronic structure engineering through Fe-doping CoP enables hydrogen evolution coupled with electro-Fenton

Abstract Improving the utilization of energy in the electrochemical hydrogen evolution reaction (HER) is a meaningful but challenging task. Coupling the HER with electro-Fenton instead of oxygen evolution is an effective method. For high-efficiency electro-Fenton, herein, the electron structure of CoP/C was optimized due to the doping of Fe to improve the carrier density of CoFeP/C and produce more hydroxyl radicals (·OH), which was confirmed by both characterization and density functional theory calculation (DFT) analysis. Meanwhile, CoP/C exhibits excellent HER activity with an overpotential of 42.1 mV (vs. RHE) at 10 mA cm-2 and a Tafel slope of 59 mV dec-1 because of the favorable electron transfer vector spiny structure and the high content of P element. The electrochemical flow reactor employing CoP/C for cathodic H2 and adopting CoFeP/C for anodic electro-Fenton requires only a low constant voltage of 1.68 V. For optimal electrode adjustment, electro-Fenton can be considered as an ideal oxidation reaction to promote the energy efficiency in the rationally designed reactor. Combination HER with electro-Fenton supports that our designed reactor has high potential in the fields of sustainable energy and environmental remediation.