NS-ZnO@P–Zn nanocomposites catalysts with superior photodegradation of methyl orange through in-situ oxidation and pH-mediated dealloying of equiatomic Al50Zn50 precursors

Abstract

Mediation of solution pH play a vital role of the formation of porous architectures and dealloying the amphoteric Al50Zn50 precursors. Simultaneous active dissolution of Al and Zn elements in the equiatomic AlZn precursors occurs in dealloying solution pH 1, and porous AlZn structure tend to form due to faster dissolution of Al atoms. Rough porous Zn architectures without ZnO form in dealloying solution pH 13.3 accompanying with prevailed Al dissolution. In bulk solution pH 13, nanocomposites consisting of spindle-shaped ZnO on porous Zn (NS–ZnO@P–Zn) form due to near-electrode pH decrease down to stable pH range of ZnO species basing on in-situ pH monitoring results. In-situ oxidation and dealloying of Al50Zn50 precursors under pH mediation can govern the formation of NS-ZnO@P–Zn nanocomposites. Photodegradation performances of methyl orange by NS-ZnO@P–Zn catalysts under visible-light irradiation are much better than porous AlZn and porous Zn catalysts. NS-ZnO@P–Zn nanocomposites with band-gap of 3.10 eV exhibit superior photodegradation efficiency due to photo-induced charge separation.