This paper presents new insights on the synthesis of nano-ZnO on reduced graphite oxide (rGO) composite via a microwave-assisted route and its use as a potential sorbent to adsorb hydrogen sulfide (H2S) at ambient conditions. Depending on the synthesis methods, the nano-sized ZnO on rGO presents different characteristics, in particular the degree of nano-ZnO dispersion on the surface of the rGO. Microwave-assisted reduction was able to offer a mild reduction to the oxygen-containing functional groups attached on the surface of graphite oxide (GO). Those oxygen-containing functional groups provide the bridge and the terminal groups between zinc oxide and the rGO surface. Because those functional groups act as anchor sites for metal ions, it was possible to achieve uniformly distributed nano-sized ZnO particles on the surface of the rGO sheets. In addition, they accelerate oxygen activation for H2S adsorption. H2S adsorption tests at ambient conditions were conducted. The 1-D carbon nanotubes (CNTs) had been used for reference in order to investigate the functionality of 2-D rGO substrate. Also, the effects of the different synthesis methods (microwave vs. reflux) were evaluated for H2S adsorption. The adsorption capacity increased dramatically for the microwave-assisted composite compared to the composite manufactured using the reflux method. (C) 2013 Elsevier B.V. All rights reserved.