There is an apparent anodic and cathodic polarization after the adsorption of metal ions. The shift toward positive potential, i.e., anodic polarization, of CelloPaper after adding ZIF indicates the possibility of electrons withdrawing from the electrode. There is a significant cathodic polarization (the working electrode becomes more negative) after the adsorption of Co 2+ ions. These observations indicate that CelloZIFPaper can be used as a working electrode for electrochemicalbase sensing of metal ions (Fig. ). LSV measurements of CelloZIFPaper before and after metal ions deposition were recorded (Fig. ). The output current of CelloZIFPaper shows changes upon interaction with different metals.