Add Graphene unit cell at the ‘Preset Structure’. Clone the cell sufficiently. Click mouse right button to popup Select window. Select atoms to determine where Cobalt be added. Add Cobalt at the ‘Add atom’ menu. Select the Cobalt atom and move vertically to graphene basal plane. Click ‘x’ key to see yz plane Add Quantum Espresso module Click ‘Structure Builder’ module to assign the model as a DFT calculation model. Setting input parameters with GUI. Put the Job name. Click ‘Start Job!’ to perform DFT calculation. Repeat calculation. Add ‘Charge Density’ module. Connect to the three Quantum Espresso modules. Click ‘Diff’ tab to display the Charge Density Difference. Set isovalue at the setting window.