The development of efficient catalysts is of great significance in the photocatalytic ozonation process for organic wastewater treatment. However, the effect of exposed facet and surface defect of the catalyst on the photocatalytic ozonation performance is less covered. Herein, ZnO nanocomposites with different preferentially exposed crystal facets (ZnO-rod and ZnO-disk) were synthesized and used for photocatalytic ozonation of phenol. The characterization and density functional theory calculation results demonstrated that exposed facet and oxygen vacancy promoted the separation and transfer of photogenerated charge as well as improved the adsorption and activation of ozone molecules on the catalyst surface. Consequently, the TOC removal rate in UV-O3/ZnO-disk process (62.4%) was much higher than that in the UV-O3/ZnO-rod process (41.3%) and the UV-O3 process (15%). Moreover, the identification and quenching of active species experiment results illustrated that •OH was more likely to be produced in the UV-O3/ZnO-disk process, while 1O2 was more likely to be formed over ZnO-rod. A large amount of •OH with stronger oxidation capability than 1O2 contributed to its superiority of ZnO-disk over ZnO-rod in organic pollutant removal. This work demonstrates that the engineering of crystal facets and surface defects provides an effective strategy for constructing efficient catalysts for the photocatalytic ozonation process.

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