Room temperature growth of ZnO with highly active exposed facets for photocatalytic application

In this article, the flower-like, urchin-like, and rod-like ZnOs were synthesized by a convenient atmospheric hydrothermal method. The crystalline structures, morphologies, exposed crystal faces, and specific surface areas of the as-prepared ZnO samples were analyzed. Rhodamine B (RhB) was used as the simulated pollutant to evaluate the photocatalytic performance of the ZnO nanostructures. The flower-like ZnO prepared by controlled hydrothermal method at room temperature for 2 h displayed highest specific surface area and exposed more high active { 2 1 ¯ 1 ¯ 0 } facets compared to the other two morphologies of ZnO. In addition, within 2 h of the photocatalytic reaction, the flower-like ZnO results in 99.3% degradation of RhB and produces the most hydroxyl radicals (˙OH) 47.83 μmol/g and superoxide anions (˙ O 2 − ) 102.78 μmol/g. Due to the existence of oxygen vacancies on the surface of { 2 1 ¯ 1 ¯ 0 } facets, the flower-like ZnO can efficiently catalyze the production of active oxygen, leading to the improvement in the photocatalytic efficiency.