Applied Surface Science 258 (2012) 5858–5862 Contents lists available at SciVerse ScienceDirect Applied Surface Science jou rn al h om epa g e: www.elsevier.com/locate/apsusc Synthesis and photocatalytic property of lead molybdate dendrites with exposed (0 0 1) facet Muhammad Hashim, Chenguo Hu ∗ , Xue Wang, Xiaoyan Li, Donglin Guo Department of Applied Physics, Chongqing University, Chongqing 400044, PR China a r t i c l e i n f o Article history: Received 12 February 2012 Accepted 22 February 2012 Available online 3 March 2012 Keywords: Lead molybdate Composite molten salt method Photocatalytic property a b s t r a c t PbMoO 4 dendrites have been synthesized by the composite molten salt method at 180 ◦ C. The dendritic plane is exposed on (0 0 1) facet. PbMoO 4 dendritic crystals exhibited high photocatalytic activity through the degradation of rhodamine B under the irradiation of the simulated sunlight, mainly due to the exposed facet (0 0 1). The (0 0 1) facet is assumed to provide more multi-atomic centers (PbMo 4 ), which are the origin of the active sites for hydrophilicity and adsorption of O 2 and the cause of the high photocat- alytic activity. The photocatalytic activity of the PbMoO 4 dendrites was also compared with those of the conventional catalysts, P25 (21 nm) and TiO 2 nanoparticles (50–200 nm). © 2012 Elsevier B.V. All rights reserved. 1. Introduction The properties of nanocrystals depend not only on their com- position, but also on their structure, phase, shape, size and crystallization [1–4]. Varied morphologies, such as nanoparti- cles, nanorods, nanospheres, nanoneedles, nanosheets, nanowires, nanotubes, nanobelts or nanoribbons, nanofibers, and dendrites have been presented [5–12]. The surface characteristics of pho- tocatalysts have much impact on their photocatalytic efficiency. Recent investigations have proved that exposed facets of semi- conductor oxide photocatalysts can remarkably improve their photocatalytic activity because of their higher surface energy, more oxygen defects and intraplane vacancies [13–15]. Normally, TiO 2 catalyst with exposed (0 0 1) facet exhibits better photocatalysis due to its higher surface activity than that of other low index facets [16,17]. Recently, Shen et al. [13] demonstrated that the PbMoO 4 microcrystals with preferentially exposed (0 0 1) facet exhibit higher catalytic activity than that of (1 0 0) facet. Simi- larly, Xi and Ye found that the m-BiVO 4 nanoplates synthesized by a hydrothermal method with preferentially exposed (0 4 0) facet exhibit greatly enhanced activity for the photodegradation of organic contaminants and the photooxidation of water for O 2 production [15]. Anyhow, it is a great challenge to synthesize the photocat- alysts which possess both high photocatalytic activity and fast and low cost recyclability with stable catalytic activity. Herein, we reported the synthesis of lead molybdate (PbMoO 4 ) dendritic ∗ Corresponding author. Tel.: +86 23 65678362; fax: +86 23 65678362. E-mail address: hucg@cqu.edu.cn (C. Hu). nanocrystals with preferentially exposed (0 0 1) facet by a facile composite molten salt (CMS) method without using any surfac- tant or capping agent, which is a new strategy for the synthesis of nanomaterials using two salts as solvent [10,18,19]. The pho- tocatalytic activity of the PbMoO 4 dendrites with preferentially exposed (0 0 1) facet is evaluated by the degradation of rhodamine B (RhB) dye under the simulated sunlight irradiation and the results were compared with common commercial catalysts, P25 and TiO 2 nanoparticles. The well recyclability with a stable catalytic activ- ity of the PbMoO 4 dendrite catalyst has been verified through RhB degradation. 2. Experimental 2.1. Synthesis of PbMoO 4 dendritic nanocrystals All chemicals purchased from Chongqing Chemical Company were analytically pure and used without further purification. PbMoO 4 dendritic nanocrystals have been synthesized by the CMS method. Typically, 3 g of LiNO 3 and KNO 3 with mass ratio of 1:2 were mixed in a Teflon vessel of 25 mL capacity. Then, 1 mmol of Pb(NO 3 ) 2 and H 2 MoO 4 and 4 mL ammonia solution (pH 9) were added in the Teflon vessel. After reacting at 180 ◦ C for 23 h in a furnace, the vessel was taken out and allowed to cool at room tem- perature naturally. Finally, the sample was obtained after washing the product several times with distilled water and absolute ethanol. 2.2. Characterization The crystal phase of the sample was characterized by X-ray diffractometer (XRD, BDX320) equipped with graphite 0169-4332/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2012.02.116