Germanium-incorporated lithium silicate composites as highly efficient low-temperature sorbents for CO2 capture

Carbon dioxide emission from massive point sources such as industries and power plants is perceived to be a major contributor towards global warming and associated climate changes. Although lithium silicate has the highest capacity for CO2 sorption (8 mmol g(-1)), it is kinetically limited during the sorption process, particularly at temperatures below 500 degrees C. Herein, we report a facile strategy for the development of germanium-incorporated lithium silicate composites, which display enhanced CO2 absorption capacity as well as kinetics in the temperature range of 150-680 degrees C. The absorption capacity of 324 mg g(-1) at the rate of 117 mg g(-1) min(-1) was measured at 680 degrees C, and 49 mg g(-1) at the rate of 36 mg g(-1) min(-1) was measured at 300 degrees C for samples with a Si : Ge molar ratio of 1 : 0.183. This study thus highlights the possibility of employing germanium-incorporated lithium silicates for the absorption of CO2 at a wide range of temperatures, including the in situ removal of CO2 from chemical and petrochemical reactions, such as the water-gas shift reaction occurring at low temperature ranges of 150-450 degrees C, that has hitherto been not possible with pure Li4SiO4.