Nitrophenols are one of the most common organic pollutants in industrial and agricultural wastewater. In recent years, due to the excellent catalytic properties of nano-Au catalytic materials, as highly efficient, fast and eco-friendly catalysts, nano-Au catalytic materials have been widely applied to the reduction of 4-nitrophenol. Correspondingly, synthesis of highly dispersed, size controllable, long-term and recycleable nano-Au catalytic materials is the main stream of this field. Based on the overall structure of the nano-Au catalytic materials, this review summarizes the latest progress on this direction, especially for the preparative methods, catalytic performance, stability, recyclability and reusability. Finally, the remaining problems and the future developing prospects are also proposed.

Contents
1 Introduction
2 Nano-Au catalyst and its catalytic performance
2.1 Polymer-based elastic nanocatalysts
2.2 Hollow spherical nanocatalysts
2.3 Core@shell structured nanocatalysts
2.4 Yolk@shell-like nanocatalysts
2.5 Other nanocatalysts
3 Conclusion and outlook