Fabrication of novel p-CuO/n-ZnO heterojunction nanofibers by electrospinning for enhanced photocatalytic performance in the denitrification of fuel oil

CuO/ZnO p-n heterojunction nanofibers were fabricated by coupling p-type CuO with n-type ZnO nanofibers for efficacious elimination of pyridine in fuel oil. The structural and photoelectric characteristics of the as-synthesized nanofibers were systematically studied. The photodegradation system was appropriate for the oxidation of pyridine from fuel oil utilizing the ambient air without mixing with other oxidants. Under visible light illumination, more than 90% of the pyridine (100 mL, 100 μg/g) could be degraded within 60 min by 17.5 mg of MCuZn-0.5 (the photocatalyst with a Cu/Zn molar ratio of 0.5 at%). The visible-light-induced photocatalytic denitrification efficiency of the MCuZn-0.5 nanofibers was nearly 1.5 times as high as that of ZnO alone. The superior denitrification activity of p-CuO/n-ZnO heterojunction nanofibers could be attributed to the enhanced optical absorption capacity and efficacious separation of photoexcited charge pairs. In addition, five-cycle experiments confirmed that MCuZn-0.5 nanofibers also displayed satisfactory photocatalytic denitrification properties. Mechanistic investigations proposed that the photoexcited holes played a dominant role in the formation of reactant intermediates, while superoxide radicals promoted the ultimate mineralization process of pyridine.