A new catalytic opportunity for waste materials: Application of waste slag based catalyst in CO2 fixation reaction

•A strategy that contributes to both waste and carbon management is proposed.•Layered double hydroxide (LDH) compound can be synthesized from blast furnace slag.•The slag-made LDH efficiently catalyzes the addition reaction of epoxides with CO2.•The slag-derived impurity elements act as catalyst promoters.

Iron and steel industry is one of the most energy-intensive industries, consuming 5–6% of the world's total energy consumption and emitting 5–7% of total world CO2 gas emissions. Large volume of CO2 emitted from iron and steel industry makes a significant contribution to global warming and climate change. Blast furnace slag (BFS), a high volume mineral waste discharged from iron and steel making processes, can potentially be used as an abundant and low-cost precursor for synthesizing active materials of catalytic interest that utilize the emitted CO2 in synthetic chemistry. In this study, we demonstrate that a Ca-based layered double hydroxide (LDH) compound can be synthesized from BFS through a facile synthetic procedure, and the thus synthesized material acts as a solid base catalyst that efficiently catalyzes the cycloaddition reaction of epoxides with atmospheric pressure of CO2 to give five-membered cyclic carbonates. The strategy proposed in this study would be one of the possible approaches that contribute to both efficient utilization of CO2 and waste management problems lying in iron and steel industry.

Graphical abstractBlast furnace slag, a high volume byproduct resulting from iron and steel making industry, was used as an inexpensive and abundant precursor for the preparation of layered double hydroxide (LDH) compound. The synthesized LDH worked as an efficient heterogeneous base catalyst for the cycloaddition reaction of epoxides with 1 atm CO2 to provide five-membered cyclic carbonates.Figure optionsDownload full-size imageDownload as PowerPoint slide