Pseudophysical sorption of aluminum in carbon honeycomb structures

Carbon honeycomb (CH) cellular structures were first experimentally discovered and structurally identified almost ten years ago. They have previously demonstrated high sorption capacities for various gases. In this work, we elucidate the role of the other type of interatomic bonding in the anticipated uptake of aluminum in CH channels. The samples of CHs with the Al filled channels were prepared at three different temperatures T ≈ 25, 650, and 1000 °C. High-energy electron diffraction experiments, combined with structural modeling based on assumption of pseudophysical sorption of aluminum, not perturbing the matrices, revealed that CH structures can host metallic-like nanoscale aluminum rods within their channels. Three different mechanisms for filling the CH matrices with aluminum were found depending on the temperature. At room T we observed the direct Al vapor deposition in the wider CH channels, at T ≈ 650 °C the diffusive mechanism of sorption from the initially deposited Al films was found to prevail, while at T ≈ 1000 °C the Al films melted and in a liquid form penetrated inside the CH channels. The CH matrices, participating in the Al uptake, exhibit low densities, ranging from 1.28 to 1.55 g/cm³, indicating high porosity; the thinnest channels (in CHs with the higher densities) were filled at ≈ 1000 °C from the liquid Al phase. These findings highlight the potential of CH cellular structures as a versatile platform for creating new composite materials with metallic-like nanorods embedded in the CH channels.