Synthesis and characterization of Pd-doped Co nanofibers as a multifunctional nanostructure Nasser A.M. Barakat a,b,n , M.F. Abadir c , M. Shaheer Akhtar d , Mohamed El-Newehy e , Yu-shik Shin a , Hak Yong Kim a,n a Organic Materials and Fiber Engineering Department, Chonbuk National University, Jeonju 561-756, Republic of Korea b Chemical Engineering Department, Faculty of Engineering, Minia University, El-Minia, Egypt c The Chemical Engineering Department, Cairo University, Cairo, Egypt d New and Renewable Energy Material Development Center (NewREC), Chonbuk National University, Jeonbuk 561-756, Republic of Korea e Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia article info Article history: Received 11 May 2012 Accepted 27 June 2012 Available online 4 July 2012 Keywords: Metallic nanofibers Electrospinning Pd-doped cobalt Photocatalyst Diode abstract Due to the axial ratio feature, bimetallic nanofibers are expected to have novel characteristics. In this study, Pd-doped Co nanofibers could be successfully prepared using simple, low cost, high yield and effective technique; electrospinning. The introduced nanofibers have been synthesized by calcination of electrospun nanofibers composed of Pd NPs/cobalt acetate tetrahydrate/poly(vinyl alcohol) in a vacuum atmosphere. The introduced Pd–Co nanofibers revealed distinct photocatalytic activity as an almost 90% from the methylene blue dye has been oxidized within 30 min. As an active layer in a diode, the introduced nanofibers showed good performance. Magnetic properties study indicated that Pd nanoparticles negatively affected the saturation magnetization of the cobalt nanofibers, however very low remenant magnetization was obtained (7.7 emu/g) compared to the un-doped Co nanofibers (69.22 emu/g) which concludes that Pd modified Co to be magnetically clean material. & 2012 Elsevier B.V. All rights reserved. 1. Introduction Recent research has indicated that bimetallic NPs containing an alloy structure of a noble metal and a first-row transition metal have composition-dependent optical, magnetic, and catalytic properties that are different from any of the monometallic NP components [1]. With proper control of size, morphology, and compositions, their physical and chemical properties can be greatly enhanced [2,3]. One-dimensional (1D) nanostructured materials have received broad interests due to their distinguished electrical, mechanical, chemical, and optical properties. A large variety of semiconductor, metallic, dielectric, and polymer materials have been synthesized in the form of 1D morphology with well-controlled sizes, orientations, and organization. Among the 1D nanostructures, nanofibers have special interest. Owing to large surface-to-volume ratio, tunable transport properties, and unique surface chemistry, nanofibers are expecting to become important building blocks for harvesting solar, thermal, mechanical, and chemical energy, as well as electrical and electrochemical energy storage. Accordingly, bimetallic nanofibers might have good catalytic properties. Recently, pure and combined first-raw transition metals have been reported in the form of nanofibers [4–9]. In this study, for the first time, Pd-doped Co nanofibers have been synthesized using a facile, low-cost and high yield technique; electrospinning. Co and Pd have been chosen as the constituents of the bimetallic nanofibers catalyst based on the fact that Co has the highest activity among the nonnoble metal catalysts [10–12] and Pd is moderately active among the precious metal catalysts [13,14], moreover it is relatively cheaper than platinum and gold. Pd-doped Co nanofibers have been prepared by electro- spinning of an aqueous colloid composed of Pd NPs, cobalt acetate tetrahydrate and poly(vinyl alcohol). Calcination of the obtained electrospun nanofibers in a vacuum atmosphere resulted in produ- cing Pd-doped Co nanofibers. The introduced nanofibers showed very good performance when they have been utilized as a photo- catalyst and an active material in a diode. Magnetic properties of the introduced nanofibers were studied and compared with the pristine cobalt nanofibers and the bulk material. 2. Experimental section Cobalt (II) acetate tetra-hydrate (CoAc) and PVA were utilized without any further modifications. To prepare Pd NPs/CoAc/PVA Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/matlet Materials Letters 0167-577X/$ - see front matter & 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matlet.2012.06.099 n Corresponding authors at: Organic Materials and Fiber Engineering Depart- ment, Chonbuk National University, Jeonju 561-756, Republic of Korea. Tel.: þ82632702363; fax: þ82632702348. E-mail addresses: nasser@jbnu.ac.kr (N.A.M. Barakat), khy@jbnu.ac.kr (H.Y. Kim). Materials Letters 85 (2012) 120–123