Construction of ZnWO4/UiO-66-NH2 heterostructures for efficient photocatalytic reduction of Cr(VI)

Hexavalent chromium in industrial wastewater poses a serious threat to ecosystems. Photocatalytic technology has been seen as a promising strategy for removing heavy metal ions. Construction of heterostructures offered a promising strategy to enhance the separation efficiency of photogenerated carriers, thereby improving photocatalytic performance. Herein, ZnWO 4 /UiO-66-NH 2 heterostructures were synthesized by a two-step hydrothermal method. The synthesized samples were systematically characterized via a variety of techniques, alongside an exploration of the associated photocatalytic mechanism. ZnWO 4 /UiO-66-NH 2 -2 exhibited an exceptional photocatalytic performance, attaining a 97 % degradation of hexavalent chromium within 60 min, approximately 1.3 and 4.7 times that of UiO-66-NH 2 and ZnWO 4 , respectively. The transient photocurrent response, photoluminescence (PL), and electrochemical impedance spectroscopy (EIS) results indicate that constructing heterostructures can effectively accelerate the migration of electrons while simultaneously suppressing the recombination process of photogenerated carriers. In addition, Active species trapping experiments revealed that the photogenerated electrons were the main active substances in photoreduction reaction. This study offers an effective strategy for photocatalytic reduction of hexavalent chromium.