Efficient photoelectrochemical cell composed of Ni single atoms/P, N-doped amorphous NiFe2O4 as anode catalyst and Ag NPs@CuO/Cu2O nanocubes as cathode catalyst for microplastic oxidation and CO2 reduction

Plastics are ubiquitous in human life and pose certain hazards to the environment and human body. The increasing amount of CO₂ in the atmosphere will lead to the greenhouse effect. Therefore, it is urgent to treat microplastic waste and CO₂ by using environmentally friendly and efficient technologies. In this work, we developed an efficient photoelectrocatalytic system composed of Ni single atoms (Ni SAs) supported by P, N-doped amorphous NiFe₂O₄ (Ni SAs/A-P-N-NFO) as anode and Ag nanoparticles (Ag NPs) supported by CuO/Cu₂O nanocubes (Ag NPs@CuO/Cu₂O NCs) as cathode for microplastic oxidation and CO₂ reduction. The Ni SAs/A-P-N-NFO was synthesized by calcination-H₂ reduction method, and it achieved a Faraday efficiency of 93% for the oxidation reaction of poly (ethylene terephthalate) (PET) solution under AM 1.5 G light. As a photocathode, the synthesized Ag NPs@CuO/Cu₂O NCs was utilized to reduce CO₂ to ethylene and CO at 1.5 V vs. RHE with selectivity of 42% and 55%, respectively. This work shows that the photoelectrocatalysis, as an environmentally friendly technology, is a feasible strategy for reducing the environmental and biological hazards of light plastics, as well as for efficient CO₂ reduction.