Oxidos De Compositos

Materials Chemistry and Physics 123 (2010) 293–299

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Materials Chemistry and Physics
journal homepage: www.elsevier.com/locate/matchemphys

A general synthesis and electrocatalytic activity of low-dimensional MO and M–Co (M Cu, Ni, Zn and Cd) composite oxides
Lu Pan a,b , Mai Xu a , ZuDe Zhang b,∗
a b

Department of Chemistry and ChemicalEngineering, Huainan Normal University, Anhui, Huainan 232001, PR China Department of Chemistry, University of Science and Technology of China, Anhui, Jinzhai Road, Hefei 230026, PR China

a r t i c l e

i n f o

a b s t r a c t
An assisting template with cyclohexylamine was used to synthesize low-dimensional Co3 O4 , MO, M–Co (M Cu, Ni, Zn and Cd) composite oxides with M/Co atomic ratio of 1:2.The as-synthesized samples were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicated that Co3 O4 and CdO possessed sheet-like morphologies, NiO demonstrated belt-like morphology, ZnO represented rod-like shape. The morphologies of the composite M–Co oxides (M Cu and Cd)represented rod-like shape, Ni–Co and Zn–Co oxides exhibited belt-like and sheet-like morphologies. According to phase analysis with XRD technology, M–Co (M Cu, Ni and Zn) possessed MCo2 O4 spinel structure but Cd–Co oxides revealed a hybrid structure. The electrocatalytic activity for p-nitrophenol reduction with a glassy carbon electrode modified with the as-prepared metal oxides or M–Co compositeoxides was investigated in a basic solution, and the results indicated that NiO and Co3 O4 showed a certain but CdO and ZnO a little electrocatalytic activity for p-nitrophenol reduction, while M–Co composite oxides all revealed high electrocatalytic activity for the reduction of p-nitrophenol. © 2010 Elsevier B.V. All rights reserved.

Article history: Received 15 January 2010 Received in revisedform 6 April 2010 Accepted 12 April 2010 Keywords: Composite oxide materials Hydrothermal synthesis Electrocatalysis

1. Introduction Individual cobalt, copper, nickel, cadmium and zinc oxide, which are the important p-type semiconductor, have been investigated extensively [1–5] and are widely applied in catalysts [6], solar cells [7,8], gas sensors [9] and so on. However, much effort has beenmade on the investigation of the composite transition metal oxides recently [10–15]. Binary and ternary transition composite metal oxides, especially containing cobalt, are important materials as potential anodes to replace graphite in present-day lithium-ion batteries [16–18], catalysts for CO oxidation [19], electrocatalysts for oxidation pollutants in wastewater [20] and magnetic materials[21,22]. A cubic Co3 O4 possesses a normal spinel structure. Several transition metal ions can replace partial or overall Co(II) in Co3 O4 structure and the normal spinel structure remains [23–25]. The combination of two oxides leads to creation of new systems with novel physicochemical properties, which may exhibit more excellent performances as compared to a single component system [26]. However,the chemical characteristics of transition metals, namely several oxidation and spin states, close cation sizes and a tendency to occupy tetra- and octahedral sites, are the factors determining

the wide spectrum of magnetic, electrical and catalytic properties of compounds with a spinel structure and their dependence on the methods of synthesis [27]. In the work, metal oxalate salt precipitationsdirected by cyclohexylamine via a hydrothermal method were used to prepare MO and M–Co composite oxides (M Cu, Ni, Zn and Cd), the as-synthesized samples possessed 1D or 2D morphologies, and M–Co composite oxides (M Cu, Ni and Zn) exhibited spinel structures. Transition metal oxides such as NiO have been used as photocatalyst to degrade pollutant in wastewater [28]. Phenol and its derivants are...