Review—Brief Review of the Solid-State Graphenothermal Reduction for Processing Metal Oxide-Reduced Graphene Oxide Nanocomposites for Energy Applications

In the recent past, metal oxide (MO)-reduced graphene oxide (rGO) nanocomposites have attracted great attention in energy applications, especially as active electrode materials in Li-ion batteries and supercapacitors. These nanocomposites are specifically designed to simultaneously tap the properties of metal oxide and graphene, making them advantageous for energy applications. The processing methods of MO-rGO nanocomposites can be broadly classified into i) rudimentary combustion, ii) post-immobilization, and ii) in situ bonding methods. Herein, the only solid-state in situ bonding method named Graphenothermal Reduction (GTR) in preparing various MO-rGO nanocomposites is reviewed. In the GTR method, the catalytic ability of carbon is used in processing the MO-rGO nanocomposites. The carbon in the starting graphenaceous material (typically GO) lowers the activation energy of the reduction reaction (which also lowers the reduction temperature) to in situ form metal oxide while the starting GO reduces to rGO in the nanocomposite. Immediate future perspectives pertaining to the GTR method are also discussed.