Germanium-incorporated Lithium Silicate Composites as Highly Efficient Low-temperature Sorbents for CO2 Capture

Abstract

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 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 C. The absorption capacity of 324 mg g 1 at the rate of 117 mg g 1 min 1 was measured at 680 C, and 49 mg g 1 at the rate of 36 mg g 1 min 1 was measured at 300 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 C, that has hitherto been not possible with pure Li4SiO4.