Sorption of 4He, H2, Ne, N2, CH4 and Kr impurities in graphene oxide at low temperatures. Quantum effects

TL;DR

This study investigates how various gas impurities are absorbed and released by different forms of graphene oxide at low temperatures, highlighting the effects of chemical reduction on sorptive capacity and the role of quantum tunneling in diffusion.

Contribution

It provides new insights into the sorption behavior of gases in reduced graphene oxide and emphasizes the significance of quantum tunneling mechanisms at low temperatures.

Findings

RGO-Hz shows 3-6 times higher sorptive capacity than GO.

Temperature dependence of diffusion coefficients suggests tunneling dominates at low temperatures.

Reduction with glucose has minimal impact on sorptive properties.

Abstract

Sorption and the subsequent desorption of 4He, H2,Ne, N2, CH4 and Kr gas impurities by graphene oxide (GO), glucose-reduced GO (RGO-Gl) and hydrazine-reduced GO (RGO-Hz) powders have been investigated in the temperature interval 2-290 K. It has been found that the sorptive capacity of the reduced sample RGO-Hz is three to six times higher than that of GO. The reduction of GO with glucose has only a slight effect on its sorptive properties. The temperature dependences of the diffusion coefficients of the GO, RGO-Gl and RGO-Hz samples have been obtained using the measured characteristic times of sorption. It is assumed that the temperature dependences of the diffusion coefficients are determined by the competition of the thermally activated and tunneling mechanisms, the tunneling contribution being dominant at low temperatures.