Low-Cost Preparation of High-Surface-Area Nitrogen-Containing Activated Carbons from Biomass-Based Chars by Ammonia Activation

Nitrogen-containing activated carbons are a new type of porous carbon materials with excellent performance in electricity storage, catalysis, and the selective adsorption, but the low-cost preparation remains a technical obstacle for practical application. In this work, ammonia activation is developed to prepare nitrogen-containing activated carbons from abundant and sustainable biomass-based chars by a one-step method. High-surface-area nitrogen-containing activated carbons are produced in yields higher than 20%, with a surface area and nitrogen content greater than 2300 m(2)/g and 5.0%, respectively. Moreover, the four successive stages in the process of ammonia activation are suggested in terms of the evolution of the pore structure with the char burnoff; the evolution of nitrogen-containing groups including pyridinic-nitrogen, pyrrolic-nitrogen, quaternary nitrogen, and -NH2 with the activation temperature are analyzed. These results indicate that ammonia activation is a new and highly efficient method for the one-step preparation of nitrogen-containing activated carbons from biomass-based chars.