Graphene oxide single layer sheets can be readily assembled into stacks with interlayer distance below 1 nm, leading to a network of nanocapillaries with sub-nm width. Therefore, the stacked rGO sheets can provide extreme confinement for a non-vdW material located within the nanocapillaries. In this study, we utilize the angstrom-confinement provided by laminated rGO to restrict the electrochemical growth of a metal oxide into two dimensions (see Figure ). The resulting sandwich structure of metal oxide and rGO was thoroughly analyzed to reveal the crystal structure of the 2D metal oxides within the interlayer network of the rGO stacks.