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

Abstract 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 NaBH4 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 (kapp) 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 kapp is well fitted into pseudo-first order kinetics with high correlation coefficient (R2) 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.