Ultrafast Photoenhanced Extraction of Uranium by Cu2o/Cuo Heterojunction from Seawater

Photocatalytic uranium extraction in seawater provides a promising strategy for the sustainable utilization of nuclear energy. Herein, we in-situ constructed Cu2O/CuO interface by a wet-etching method, achieving an ultrafast reaction kinetics and photocatalytic activity for seawater U(VI) extraction. In 8 ppm of uranium-spiked seawater, the Cu2O/CuO heterojunction exhibited a remarkable uranium extraction ratio of 94.6% within 10 min under irradiation, which exceeded most of recently reported photocatalysts. The photocatalytic reaction rate constant of Cu2O/CuO heterojunction was 5.8-time larger than that of pure Cu2O. A mechanism study indicated that the photo-generated electrons reduced CuO species in Cu2O/CuO heterojunction and in-situ created the oxygen vacancy during the photocatalysis process, which strengthened the binding of UO22+. The rapid electron transfer rate over the in-situ heterojunction interfaces and the enhanced UO22+ binding by the in-situ formed oxygen vacancy accounted for the ultrafast reaction kinetics.