Fig. 1: Preparation and characterization of {Co₄W₁₈}/rGO.

a Schematic diagram of the synthesis of {Co₄W₁₈}/rGO materials. b–d Apparent zeta potentials of GO, PEI, PEI-stabilized rGO and {Co₄W₁₈}/rGO. e SEM image, f HRTEM image, and g HAADF-STEM image of {Co₄W₁₈}/rGO sample.