Cu x OAu–ZnO nano/microstructures with various morphologies and their catalytic applications in reduction in 4-nitrophenol

In this paper, Cu x OAu–ZnO nano-catalysts with different morphologies were synthesized by one-step replacement method. The nano-catalysts are characterized by scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. These novel Cu x OAu–ZnO nano-catalysts exhibit exceptionally high stability and superior 4-nitrophenol to 4-aminophenol hydrogenation ability. The relationship between catalytic performances and changes of composition were investigated, and the catalytic activity decreased in the following order: Cu x O 30 Au 35 –ZnO > Cu x O 38 Au 35 –ZnO > Cu x O 21 Au 45 –ZnO. The influence of catalytic conditions for the performance of catalysts has also studied. For the Cu x O 30 Au 35 –ZnO catalysts, the rate constant k app could be up to 18.6 × 10 −3 s −1 , and the conversion of the 4-NP could still reach 98.66% after five cycles. The high activity of Cu x O 30 Au 35 –ZnO may be attributed to the synergistic effect between Au and Cu element. The unique structure and high catalytic performance make Cu x OAu–ZnO nano-catalysts for practical applications in 4-nitrophenol reduction.