A review of the current status of nitrogen self-doped biochar applications

Pristine biochar tends to be poorly structured and with limited active sites, inhibiting its commercial utilization. To expand the adsorption range of biochar and improve its adsorption properties and activity, functionalization with N-related groups has been proposed. However, nitrogen self-doped biochar is a material that is itself enriched with carbon and nitrogen and can be prepared from a variety of feedstocks based on animals, plants, food, algae, organic wastes, proteins/amino acids, fungi, and others. The nitrogen-containing functional groups of biochar hold the promise of a wide range of applications such as pollutant adsorption, catalytic adsorption, and energy storage. To date, many methods have been developed and used to enhance the functionality of nitrogen-containing biochar for its application and commercialization. However, there are few reviews related to the development and application of nitrogen self-doped biochar technology. The presence of N-functional groups on the surface of biochar enhances the alkalinity of the carbon surface, promotes electrostatic interactions, and facilitates the structural properties of the biochar, providing a larger interaction region, nowadays N-biochar is widely used in several fields. This paper reviews the research progress in the preparation, activation, and role played in the application of common N-doped biochar in recent years, as well as the biomasses that can be used as references for the production of nitrogen self-doped biochar. Finally, challenges and prospects for the application of nitrogen self-doped biochar in several fields are presented.