This proposal concerns the adsorption behaviour of an electron-transfer protein, cytochrome c, on modified electrode surfaces. Cytochrome c plays an important role in transferring electrons across membranes, for example during photosynthesis. Bioelectrochemical devices that use light-harvesting biofilms to generate electricity are limited by slow electron transfer at the electrode surface, and so understanding how proteins such as cytochrome c interface with these electrodes is crucial for improving this technology. We previously successfully used an electrochemical neutron reflectometry cell to demonstrate subtle but significant changes in the protein structure on stainless steel as a potential was applied and in this proposal we hope to extend the research to consider modified gold and indium tin oxide electrodes, on which the electron transfer has been shown to be greatly improved.