Nanotechnology approach for enhancement in biohydrogen production-review on applications of nanocatalyst and life cycle assessment

Renewable energy research has gained momentum due to the fast consumption and lack of sustainability in conventional fuels. As biohydrogen emits no greenhouse gases and can be generated from a variety of waste biomass or feedstocks, it has been referred to as the most effective and cleanest form of energy among all biofuels. In spite of the success of photobiological and dark fermentation methods in generating biohydrogen, they are known to produce lower yields, creating serious obstacles for commercial production. The role of nanoscience and technology in improving the biohydrogen production is achieved through the use of nanomaterials with specific physiochemical and structural properties. In this review, metals, metal oxides, metal alloys, and inorganic nanomaterials are explored in order to improve biohydrogen production. Initial studies have focused on nano materials evaluation in biomass conversion and addressing the current status of nanomaterials in biohydrogen production. The best bio-H-2 yield is obtained in the presence of metal nanoparticles (NPs) such as Ag (2.4 mol H-2/mol glucose), Cu (1.74 mol H-2/mol glucose), Fe (3.10 mol H-2/mol malate), alloys of Al/Cu/Fe (4.2 mol H-2/sucrose) and Ni (2.54 mol H-2/glucose). The review also addressed the mechanisms involved in changing feedstock into hydrogen through various microbial biorefineries. The life cycle analysis of various nanoparticles applications in biohydrogen production was discussed.