One-Step Synthesis of Graphene-Cobalt Hydroxide Nanocomposites and Their Electrochemical Properties

The well-documented novel performances of graphene make it a potential candidate for a wide range of utilizations, driving research into exploiting unusual properties of this wonder material. This paper reports a facile soft chemical approach to fabricate graphene-Co(OH)(2) nanocomposites in a water-isopropanol system. Generally the depositing agent (OH-) and some reducing agents (such as HS- and H2S) could be produced from the hydrolyzation of Na2S in aqueous solution. Therefore utilizing Na2S as a precursor could enable the occurrence of the deposition of Co2+ and the deoxygenation of graphite oxide (GO) at the same time. Remarkably the electrochemical specific capacitance of the graphene-Co(OH)(2) nanocomposite reaches a value as high as 972.5 F.g(-1), leading to a significant improvement in relation to each individual counterpart (137.6 and 726.1 F.g(-1) for graphene and Co(OH)(2), respectively). The feeding ratios between Co(OH)(2) and graphene oxide have a pronounced effect on their electrochemical activities.