ORIGINAL RESEARCH Facile Synthesis of Cobalt Oxide Nanoparticles by Thermal Decomposition of Cobalt(II) Carboxamide Complexes: Application as Oxygen Evolution Reaction Electrocatalyst in Alkaline Water Electrolysis Soraia Meghdadi 1 & Mehdi Amirnasr 1 & Mohammad Zhiani 1 & Fariba Jallili 1 & Meysam Jari 1 & Mahsa Kiani 1 # Springer Science+Business Media New York 2016 Abstract Cobalt oxide nanoparticles, Co 3 O 4 (1) and Co 3 O 4 (2), have been synthesized by thermal decomposition of [Co II (bqbenzo)] and [Co II (bqb)], respectively. The morpholo- gy of these oxides is influenced by the difference in the struc- ture of bqbenzo 2- {3,4-bis(2-quinolinecarboxamido) benzo- phenone and, bqb 2- {bis(2-quinolinecarboxamido)-1,2- benzen}, only differing in a benzoyl substituent. The products were characterized by XRD, FE-SEM, and FT-IR spectrosco- py. The catalytic activity of the oxides was examined in oxy- gen evolution reaction (OER) by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The Co 3 O 4 oxides (1 and 2) exhibited higher catalytic activity compared to 10 wt% Pt/C in terms of obtained current density at 0.8 V; ∼23.3 ver- sus 6.1 mA cm -2 , respectively. However, the aging tests of the two oxides in OER revealed that Co 3 O 4 (1) is more stable than Co 3 O 4 (2). These results demonstrated that the Co 3 O 4 (1) has a superior performance which can be employed in the alkaline water electrolyzer anode. Keywords Cobalt carboxamide complex . Co 3 O 4 nanoparticles . Oxygen evolution reaction . Water oxidation . Anode catalyst Introduction Electrocatalytic transformation of water to H 2 and O 2 has attracted increasing attention for producing clean energy and efficient energy storage [1–3]. The oxygen evolution reaction (OER, 4H + /4e ─ ), which requires a large overpotential, is one of the major scientific challenges in this transformation [4–6]. Although, the oxides of some noble metals such as Ru and Ir exhibit excellent activity towards OER [7–9], it is highly de- sired to search for efficient and low-cost OER catalysts to reduce the overpotential and enhance the current density. In recent years, tremendous efforts have been dedicated to searching for inexpensive OER electrocatalyts. Amongst the most promising materials that have displayed a combination of desired stability, relatively low overpotential, and viable cost are various transition metals and metal oxides, including cobalt oxides [10–12] and nickel oxides prepared by different methods [13–15]. To get a better performance however, cobalt oxide nanoparticles have been used to fabricate metal oxide- based electrodes. These nanoparticles are prepared by a vari- ety of synthetic methods using different precursors, including thermal decomposition of suitable cobalt coordination com- pounds [16]. In this context, several cobalt complexes such as Co(C 6 H 5 COO) 2 (N 2 H 4 ) 2 [ 17 ] and [(NH 3 ) 5 Co(O 2 ) Co(NH 3 ) 5 ](NO 3 ) 4 [18] have been used for the synthesis of Co 3 O 4 NPs by thermal decomposition. However, more con- venient and benign synthesis of the precursors from readily available reagents is highly desirable. Pyridine carboxamide ligands and their metal com- plexes are amongst the well distinguished and available compounds that are very attractive to inorganic chemists due to their diverse applications. These compounds have exhibited extraordinary properties and have been exploited in a great variety of catalytic and biological Electronic supplementary material The online version of this article (doi:10.1007/s12678-016-0345-7) contains supplementary material, which is available to authorized users. * Soraia Meghdadi smeghdad@cc.iut.ac.ir * Mehdi Amirnasr amirnasr@cc.iut.ac.ir 1 Department of Chemistry, Isfahan University of Technology, Isfahan 8415683111, Iran Electrocatalysis DOI 10.1007/s12678-016-0345-7