Summary
At present, the energy requirements of the world majorly depend on fossil fuels, but overconsumption leads to a serious energy crisis, and the greenhouse gases released during the burning of fossil fuel arouse various environmental issues like global warming, acid rain, etc. Biohydrogen is one of the promising fuel among the alternative sources of energy, because it can be derived from renewable sources, cost effective, high energy content, clean, and environmentally friendly fuel. Biohydrogen has been produced by various methods namely thermo‐chemical gasification, solar gasification, electrolysis of water, pyrolysis, steam reforming, and biofermentation. Among them, the biological way of hydrogen production is an environmentally friendly method and does not require any external energy, but beside hydrogen dark fermentation could also generate CO2 and other gases as by‐products, which could contribute to the greenhouse gas augmentation if not well‐controlled. But the quantity of hydrogen production through the photo and dark fermentation method is low, which is also a major constrain for commercialization. In order to overcome this obstacle, many researchers engaged them in the biohydrogen production with nanotechnology which is a potential technique for efficient biohydrogen production. Hence, this review is mainly focused to providing an update of nanotechnology in biohydrogen production and state‐of‐the‐art on its emerging field. In this regard, this review paper highlighted several new findings and achievements in biohydrogen production using both inorganic and organic nanoparticles. Additionally, the synthesis of sustainable and environmentally friendly green nanoparticles in biohydrogen production has been addressed.