Graphene@Metal Nanocomposites by Solution Combustion Synthesis

Abstract

Graphene (G) and metal-decorated G nanocomposites are among the most promising materials for a wide variety of practical applications, and, therefore, the development of fast and reliable methods for nanocomposite synthesis is an important task. Herein we report the new fast approach for solution combustion synthesis (SCS) of large-area G−metallic nanocomposites in an air atmosphere. The G-based nanocomposites were obtained by a SCS using copper and nickel nitrates, as well as their stoichiometric mixture as the metal source and citric acid as a fuel and carbon source. The G structures started on the catalytic surface of freshly synthesized metallic nanograins during the combustion process and formed large-area freestanding films due to the high-energy and fast synthesis process. We proposed a mechanism of formation of the G-based nanocomposites. The phase compositions, structural features, and magnetization behavior of G@Cu, G@Ni, and G@CuNi nanocomposites are carefully studied and described. G@metal nanocomposites were studied as a material for the creation of a highly effective sensing element of semiconductor gas sensors.

CO oxidation and organic dyes degradation over graphene–Cu and graphene–CuNi catalysts obtained by solution combustion synthesis

“…The G-band peak position corresponds to the tri-layered G structure 23 . The calculated peaks intensity ratio I D /I G of 1.254 indicates highly distorted or/and defected G structure, characteristic to scsG phase, described in detail earlier 14 . The D-and G-bands were also founded at 1327 cm −1 and 1584 cm −1 at the Raman spectrum of the G@CuNi sample (Fig.…”

“…The distorted structure of scsG could be explained by features of their formation mechanism during high-intensive fast SCS reactions. In this case, scsG film growth starts on metallic nanograins and then develops due-to a self-catalytic process, where products of CA decomposition play the role of carbon atoms source 14 . The combination of a local temperature gradient, gradients of concentration of reacting components, and products of reaction could create conditions for the start of growth of scsG from the multiple metallic clusters, simultaneously.…”

“…The experimental samples were obtained by the SCS method as described in our previous article 14 . Briefly, in typical experiments, 12.23 g of citric acid (CA, Chimmed, 98.9%; Russia) and 3.78 g of Cu(NO 3 ) 2 •3H 2 O (Chimmed, 98%; Russia) (G@Cu sample), or 12.09 g of CA, 1.89 g of Cu(NO 3 ) 2 •3H 2 O and 2.47 g of Ni(NO 3 ) 2 •6H 2 O (Chimmed, 99%; Russia) (G@CuNi sample) were dissolved in hot distillate water.…”

“…The fast drying allows obtaining precursor in the form of a porous easy combustible foam. The temperature of the furnace for SCS reaction initiation was chosen based on an analysis of the result of our previous study 14,36,37 . It was shown, the decomposition of the precursor as a result of the combustion reaction mostly finishes up to ∼ 500 °C.…”

“…Recently, composite nanopowders, consistent from newly developed G-type nanostructure, named scsG, on Cu and CuNi nanograins, were obtained by one-step solution combustion synthesis (SCS) 14 . Using the high-intensive SCS reaction allowed to combine the formation of Cu and CuNi nanograins, which are known to be among the best catalysts for controllable G growth 15 , with simultaneous catalytic activation of scsG formation.…”