Cellulose nanofiber aerogel as a potential receiver layer for solar application: a review

The population explosion, industrialization, and technological advancements have resulted in fast-growing energy demand around the world. Hence, there is a requirement for reliable and sustainable energy for addressing the long-term energy crisis. In this context, solar energy-based developments are gaining traction steadily all over the world owing to the ever-increasing energy demands while conventional energy sources are depleting and often used as geopolitical tools. To maximize the growth potential and identify the increasing concerns regarding sustainability, different materials have been developing around the world. Nanocellulose is a biomass-derived emerging material consisting of cellulose fibrils having a width in the order of the nanometer range (i.e. 2–100 nm) that can also form complex structures like aerogels. The nanocellulose aerogels combine intriguing interconnected three-dimensional porous characteristics of aerogel-type materials such as high porosity, large surface area, and low density. This paper discusses the different fundamental concepts of solar energy generation using nanocellulose aerogels. Moreover, the key properties of cellulose nanofiber aerogel in the solar thermal technology applications such as high porosity, mechanical strength, thermal stability, optical properties, and thermal conductivities were discussed in detail. This contribution also introduces different articles published in recent years about nanocellulose-based porous materials in the fields of solar thermal technology and their future.