Polyol Solvation Effect on Tuning the Universal Growth of Binary Metal Oxide Nanodots@Graphene Oxide Heterostructures for Electrochemical Applications

Tuning the uniformity and size of binary metal oxide nanodots on graphene oxide (BMO NDs@GO) is significant but full of challenges in wet-chemistry, owing to the difficulties of controlling the complicated cation/anion co-adsorption, heterogeneous nucleation, and overgrowth processes. Herein, the aim is to tune these processes by understanding the functions of various alcohol solvents for NDs growth on GO. It is found that the polyol solvation effect is beneficial for obtaining highly uniform BMO NDs@GO. Polyol shell capped metal ions exhibit stronger hydrogen-bond interactions with the GO surface, leading to a uniform cation/anion co-adsorption and followed heterogeneous nucleation. The polyol-solvated ions with large diffusion energy barrier drastically limit the ion diffusion kinetics in liquids and at the solid/liquid interface, resulting in a slow and controllable growth. Moreover, the synthesis in polyol systems is highly controllable and universal, thus eleven BMO and polynary metal oxide NDs@GO are obtained by this method. The synthetic strategy provides improved prospects for the manufacture of inorganic NDs and their expanding electrochemical applications.