Reduction of graphene oxide via application of an argon plasma jet array

This study demonstrates the efficacy of a reconfigurable argon plasma jet array for the rapid, chemical-free reduction of graphene oxide (GO). The device operates in single-, double-, and quadruple-tube configurations, enabling adjustable treatment areas and discharge intensities. Under optimized conditions, the quadruple-tube plasma configuration achieves a remarkable deoxygenation of GO, quantified by X-ray photoelectron spectroscopy (XPS) analysis showing a reduction in the combined atomic concentration of carbon atoms in C–O and C=O bonds from 48% to 27%, corresponding to removal efficiency of 44%. This is complemented by a mass loss of 44%, indicating the evolution of volatile carbon oxides. Structural analysis confirms the transformation, with X-ray Diffraction (XRD) showing the collapse of the interlayer spacing from 0.84 nm to 0.35 nm and Raman spectroscopy revealing an increase in the D/G band ratio from 0.99 to 1.03, consistent with defect generation and graphitic network restoration. The resulting reduced GO exhibits significantly enhanced hydrophobicity, with a water contact angle increase of 91.9%. The synergistic effect of energetic plasma species facilitates the cleavage of C–O/C=O bonds, leading to efficient reduction. This work highlights the potential of the flexible jet array for production of nano-materials in energy storage applications.