Pure and cerium‐doped zinc oxides: Hydrothermal synthesis and photocatalytic degradation of methylene blue under visible light irradiation

Abstract Pristine and cerium‐doped zinc oxides with a different dopant concentration between 1 and 5% were fabricated using the hydrothermal method. Prepared materials show direct bandgaps of comparable values. Cerium‐doped materials show UV‐Vis spectra with broad tails toward the visible light range. Pure zinc oxide displays the flower‐like form, while cerium‐doped materials possess rod‐shaped morphologies. The materials were tested for the degradation performance of methylene blue under visible light irradiation. To elucidate the difference in their performance, further measurements and experiments were conducted. Overall, 3%‐cerium doped zinc oxide shows the greatest photocatalytic performance. This is possibly attributed to its rod shape with good uniformity and to the enrichment of oxygen vacancies in its surface layers. Finally, trapping experiments reveal that positive holes and hydroxyl radicals were the predominant active species during the photocatalytic degradation process.