Synergy of developed micropores and electronic structure defects in carbon-doped boron nitride for CO2 capture

With the aim of relieving the serious environmental and climate issues arising from excessive emission of anthropogenic CO2, extensive solid absorbents have been developed for CO2 capture. Among them, porous boron nitride (BN) is considered an ideal candidate due to its high specific surface area, abundant structural defects, low density, and outstanding chemical inertness. Herein, BN absorbents were synthesized from pyrolysis of melamine-boric acid precursors, and the effect of pyrolysis temperature (900, 1000, 1050 and 1100 degrees C) on the properties and performances was investigated. Various characterizations were performed to evaluate the physicochemical properties and CO2 uptake capacities of BN absorbents. The result demonstrated that a carbon-doped BN structure was achieved instead of a pure BN material, and the carbonization degree was enhanced with the increase of pyrolysis temperatures. BN absorbent pyrolyzed at 1100 degrees C exhibited the highest CO2 adsorption capacity of 3.71 mmol/g (273 K). The reason should be that the doping of carbon in the framework of BN contributed to the formation of abundant micropores, which enhanced the physical adsorption by offering more adsorption sites. At the same time, more negative charges on BN were induced by structural defects, which favored the chemical adsorption of CO2 by invoking charge-induced chemisorption interaction. This study clarified the role of pore structure and electronic structure defects in CO2 adsorption capacity of carbon-doped BN, which would open up more spacious avenues for the development of promising BN-based absorbents, or even catalysts. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Porous boron nitride (BN) has been developed as an absorbent for CO2 capture to alleviate environmental and climate issues caused by excessive anthropogenic CO2 emissions. This study investigated the effect of pyrolysis temperature on the properties and performances of BN absorbents synthesized from melamine-boric acid precursors. It was found that higher pyrolysis temperatures resulted in a higher carbonization degree and enhanced CO2 adsorption capacity. The BN absorbent pyrolyzed at 1100 degrees C exhibited the highest CO2 adsorption capacity.