The excellent photocatalytic performance of a commercial ZnO (C-ZnO-1) was demonstrated. This ZnO showed approximately 3.8, 7.4 and 5.2 times greater activity than P25 TiO2 for the degradation of rhodamine B, methyl orange and methyl blue, respectively. After compounding with Ag, the catalyst showed record-high activities for the degradation of the three dyes (approximately 9.5, 13, and 50 times that of P25). The high activity of C-ZnO-1 is attributed to the low concentration of bulk defects (i.e., a high degree of crystallinity) and the relatively high number of surface defects (i.e., a higher ratio of surface hydroxyl oxygen). (C) 2017 Elsevier B.V. All rights reserved.