Bifunctional modulation of Ce4+ doping for ZnWO4 morphological structure and bandgap width to enhance photocatalytic degradation and electrochemical energy storage

ZnWO4 nanomaterials are gaining attention as a kind of multifunctional material in the field of electrochemical energy storage and photocatalysis. However, the controllable adjustment of their nanomorphology and bandgap width limit their wide application. So the nanostructured bifunctional Zn1−xCexWO4 (x = 0.020, 0.022, 0.030) with tunable nanomorphology and bandgap width were prepared by a simple one-step hydrothermal method in this work. On the one hand, the microscopic morphology of the Zn1−xCexWO4 was changed from clusters to nanosheets with the addition of Ce4+. On the other hand, the doping of Ce4+ generated oxygen vacancies and formed defect states in the ZnWO4 semiconductor, reducing the energy bandgap width. Zn1−xCexWO4 (x = 0.022) with the optimal doping ratio (nCe/(nCe + nZn) = 0.022) obtained a specific capacitance of 267.091 F g−1 at a current density of 1 A g−1 and an electrolyte of 6 M KOH, which is 3.7 times as great as the specific capacitance of ZnWO4 (70.545 F g−1). In addition, the catalytic efficiency of Zn1−xCexWO4 (x = 0.022) for Rhodamine B (RhB) reached 99.541% in 4.5 h. The doping of Ce4+ can achieve the dual modulation of the morphology and bandgap width of ZnWO4, thus enhancing the electrochemical performance and photocatalytic degradation performance of ZnWO4.