Layer‐by‐Layer Assemblies of Montmorillonite and Bacterial Cytochromes for Bioelectrocatalytic Devices

Clay‐based layer‐by‐layer architectures are studied in view of the development of new electrode materials for two highly attractive enzymatic reactions: metal bioremediation and hydrogen uptake. The buildup of layer‐by‐layer (LBL) assemblies of positively charged specific mediators of these enzymatic reactions and negatively charged montmorillonite nanoparticles were carried out onto gold and graphite electrodes. The structure and stability of the assemblies were examined using quartz crystal microgravimetry (QCM) and electrochemical techniques. Satisfactory catalytic efficiencies were observed through the LBL construction, either for bacterial cytochrome c₃‐mediated metal reduction, or hydrogen uptake via immobilized hydrogenase in the presence of an artificial shuttle, methylviologen. Interestingly, it is established that intercalating cytochrome c₃ layers between hydrogenase/montmorillonite layers not only protects hydrogenase from leaching, but allows H₂ uptake/evolution catalytic reaction without any additional diffusing redox mediator.