Co3O4-ZrO2 nanocomposites: simple preparation and enhanced photocatalytic performance for cyanide degradation under visible light

Zirconium dioxide (ZrO 2 ) has a wide band gap and fast electron-hole recombination rate. Therefore, the photocatalytic activity of ZrO 2 is very small, and it absorbs ultraviolet region. Thus, the separation of electrons and holes can enhance the photocatalytic activity of ZrO 2 . Here, Co 3 O 4 -ZrO 2 nanocomposites were synthesized using a sol-gel route utilizing cetyl trimethylammonium bromide as a template. The degradation of cyanide was used as a control test to evaluate the performance of the photocatalytic activity of the Co 3 O 4 -ZrO 2 photocatalysts. The findings demonstrate that the weight percent of cobalt oxide could be reduced the band gap energy of zirconium dioxide. The band gap of ZrO 2 was reduced from 3.42 to 2.65 eV by the addition of 3 wt% Co 3 O 4 . The photodegradation efficiency reached 100% within 30 min using a 3 wt% Co 3 O 4 -ZrO 2 photocatalyst. The 3 wt% Co 3 O 4 -ZrO 2 photocatalyst can be used five times with stable photocatalytic activity.