The gorgeous transformation of paper: From cellulose paper to inorganic paper to 2D paper materials with multifunctional properties

Cellulose paper derived from plants is used for daily writing and recording, and has historically played an important role in promoting cultural dissemination and inheritance. However, it attracted more and more attentions in recent years serving as a flexible platform or substrate for application in environment and energy, attributing from its many inherent advantages such as biocompatibility, biodegradability, sustainability, low cost, and great capability to be modified. With the development of various industries, especially the flexible electronics industry, the demand for two-dimensional (2D) paper-like materials has increased. Several kinds of inorganic paper are manufactured and have been widely used in many fields. Among them, there are hydroxyapatite (HAP)-based and carbon-based inorganic paper that give play to their own advantages and have been well applied in some fields. In addition, there are many composite papers, which are assembled from several raw materials (cellulose fibers, HAP, carbon), exhibiting excellent characteristics. Cellulose paper is no longer limited to traditional writing applications, but has great potential to be used in many aspects, achieving a gorgeous change in its role. The emergence of inorganic paper and hybrid paper has further demonstrated the application prospects of paper-like two-dimensional materials. This paper will start from the characteristics of the three types of paper and composite paper, and summarize their typical applications in the environment and energy fields.