Formate dehydrogenase immobilised on PEC cathode for CO₂ Utilization

Recently, the direct conversion of the waste CO₂ emission as feedstock into valuable chemicals has attracted increasing research interest world widely. A number of approaches such as chemical, electrochemical, photochemical or biological routes have used CO₂ as a sustainable carbon resource for the production of chemicals. In our work, a novel hybrid photoelectrochemical cell by using formate dehydrogenase (FDH) as biocatalyst was applied, to convert CO₂ into energy-rich compounds. Therefore, it becomes imperative to immobilise FDH onto the surface of cathode with high electron transfer efficiency. In this work, several metallic substrates and carbon-based materials, such as carbon nanotube and graphene coating, were selected as electrodes to immobilise FDH enzyme onto their surfaces. In order to achieve an efficient immobilization, both chemical and physical functionalization were applied to the selected surfaces. A fast antibody-based dot blot method was established to detect the efficiency of the immobilization of the proteins. The activity of the purified enzymes was investigated by measuring the conversion ratio of NADH to NAD+. Preliminary results showed that the attachment of enzymes strongly depends on surface treatment of the electrodes. The immobilization of the enzymes was significantly improved by forming chemical bonding between the enzyme and the carbon-based materials. The electron transport and activity of the enzyme on the electrode surface will be investigated.