Facile synthesis approach for preparation of robust and recyclable Ag/ZnO nanorods with high catalytic activity for 4-nitrophenol reduction

In this work, Ag/ZnO nanorods are prepared via simple and cost-saving liquid precipitation citrate reduction process (LPCR). The system shows appreciable catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) wherein NaBH 4 is used as electron sacrificer at ambience. It is found out that ZnO nanorods can effectively prevent Ag NPs agglomeration; a problem normally reduces active sites density. The coupling effect between the Ag NPs and ZnO greatly enhances electron transfer rate. This gives rise to high reduction rate constant ( k app ) of ˜3.97 × 10 −3  s −1 for the catalytic reduction of 4-NP. The result is about 1.9times better than that of Ag NPs (2.07 × 10 −3  s −1 ). The k app is well fitted into pseudo-first order kinetics with high correlation coefficient (R 2 ) of about 0.994, indicating chemisorptive reduction process. The remarkable performance obtained here is attributed to strong coupling effect between Ag NPs and ZnO nanorods derived from LPCR synthesis method.