ZnO nanowire morphology has been widely studied due to its unique material properties and excellent performance in electronics, optics, and photonic. Recently, photocatalytic applications of ZnO nanowire are creating an increasing interest in the environmental applications. This paper presents a low-cost and ecofriendly synthesis of ZnO with cauliflower morphology and its effectiveness in photocatalysis. 1. Introduction Organic dyes are very important and widely used in different industries such as textile, rubber, and plastic and hence one of the largest group of pollutants released into wastewaters [1]. They have caused several environmental contaminations, affecting human survival and developments. Degradation and removal of them are a great challenge for protecting the environment. However, the routine techniques for treating organic dyes are usually ineffective and costly to remove pollutions from water [2]. Nanomaterials have attracted high interest due to their noticeable performance in electronics, optics, and photonics. One-dimensional (1D) nanostructures such as nanowire, nanorods, nanofibers, nanobelts, and nanotubes have been of intense interest in both academic research and industrial applications. They also play an important role as interconnectors and functional units in the fabrication of electronics, optoelectronics, electrochemical, and electromechanical nanodevices [3]. For their application in solar energy conversion and environmental purification, among various semiconductor photocatalysts, TiO2 is much known for its strong oxidizing power and nontoxicity. But the major limitation in semiconductor photocatalysis is the relatively low value of the overall quantum efficiency, because of the high recombination rate of photo-induced electron-hole pairs at or near its surface. ZnO is a semiconductor material with direct wide band gap energy (3.37？eV) and a large exciton binding energy (60？meV) at room temperature. ZnO is currently attracting worldwide intense interests because of its importance in fundamental studies and its numerous applications especially as optoelectronic materials [4, 5], UV lasers [6]. Light-emitting diodes [7], solar cells [8], nanogenerators [9], gas sensors [10], photodetectors [11], and photocatalyst [12]. Photocatalysis is the promising process for environmental protection because of being able to oxidize low concentrations of organic pollutants into benign products [13–15]. Figure 1 shows mechanism of photocatalytic process. There are number of semiconductors that could be used as photocatalyst, such as TiO2,
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