Built-in Electric Field Enables Self-sustained Fenton-like Reaction for Water Treatment

Researchers have constructed a porous nitrogen-doped carbon layer encapsulating a Co/CoO heterojunction through programmable self-assembly. This creates an integrated oxidation-reduction system that couples peracetic acid with hydrogen peroxide under the direction of an interfacial built-in electric field.

Experimental and theoretical results show that strong electronic coupling between metallic Co and semiconductor CoO generates a robust built-in electric field. The field optimizes the electronic configuration to improve peracetic acid adsorption and activation.

It also enables selective adsorption of hydrogen peroxide from the mixed oxidant solution. The adsorbed hydrogen peroxide functions as an electron donor to sustain the Co(II)/Co(III) redox cycle. This facilitates continuous generation of reactive oxygen species for approximately 120 minutes.

The approach addresses a key challenge in achieving sustainable catalytic processes that continuously produce reactive species.

The system achieved contaminant removal rate constants between 0.3 and 0.6 per minute. It did so using an ultralow catalyst dosage of 15 milligrams per liter. Peracetic acid utilization efficiency was also significantly improved. The heterogeneous catalyst system demonstrates potential for advanced water treatment applications.

It offers a route for water purification that enables high oxidant utilization while minimizing catalyst consumption. The work received support from the National Natural Science Foundation of China and the Sichuan Science and Technology Program. Beamtime and technical support came from the XMCD-B beamlines at Hefei National Synchrotron Radiation Laboratory.