“…The ZnO and CuO supports used were prepared by a similar method to that used in our previous studies with minor adjustments . Typically, Zn(NO 3 ) 2 ⋅6 H 2 O (30 mL, 0.2 mol L −1 ) and Cu(NO 3 ) 2 ⋅3 H 2 O (30 mL, 0.1 mol L −1 ) solutions were added to C. camphora leaf extract (10 and 20 mL, respectively) in a 150 mL round‐bottomed flask and kept at RT to age for 1 h. The respective mixtures were dried in the oven at 80 °C for 10 h and then annealed at 450 °C 4 h. The obtained metal oxides were milled by using a pestle and mortar, then sieved through a 50 mm mesh, and stored for further use.…”