Abstract:
Photobiological hydrogen production from algae is considered as clean and promising energy source to substitute the fossil fuel with zero greenhouse gases emissions. Photoproduction of hydrogen by green algae has limiting factors because of oxygen inhibition and electron competing moieties like FNR (EC 1.18.1.2) and Rubisco (EC 4.1.1.39) to hydrogenase (EC 1.12.7.2). These biological regulatory mechanisms under anaerobic conditions inhibit hydrogen producing enzyme "hydrogenase" by oxygen produced at PSII through water splitting and at the same time compete for electrons with hydrogenase. Here, an innovative approach, bypassing all reported inhibitions to hydrogenase using crude enzyme extracts of algae leading towards hydrogen production has been presented. Zeolitic Imidazolate Frameworks (ZIFs) are one of the potential candidates as highly conducting networks with surface area with a possibility to be used as catalyst support. In the present study, highly active state-of-the-art Pt-NCNTFs catalyst was synthesized by pyrolyzing ZIF-67 along with Pt precursor under flowing Ar-H2 (90-10 %) gas at 700 °C. XRD analysis indicated the formation of Pt-Co alloy on the surface of the nanostructured catalyst support. The high resolution TEM examination showed the particle size range of 7 to 10 nm. Proton exchange membrane fuel cell performance was evaluated by fabricating membrane electrode assemblies using Nafion-212 electrolyte using H2/O2 gases (100 % RH) at various temperatures. The peak power density of 630 mW.cm2 was obtained with Pt-NCNTFs cathode catalyst and commercial Pt/C anode catalyst at 70 oC at ambient pressure.
