High-Performance CO2 Adsorbent from Inter layer Potassium-Promoted Stearate-Pillared Hydrotalcite Precursors

Stearate-pillared layered double hydroxide (LDH) promoted by K2CO3 as a precursor for pre-combustion of a CO2 adsorbent is presented for the first time. This novel precursor is synthesized from commercial hydrotalcite, one kind of LDH, undergoing acid-aid anionic exchange and wet impregnation processes. The pillared stearate expands the gallery height from 0.28 nm for carbonate-intercalated LDH (almost the diameter of the K ion, 0.276 nm) to a much spatial 3.4 nm for stearate-intercalated LDH, proven by characteristic diffraction peaks in powder X-ray diffraction (PXRD). Transmission electron microscopy (TEM) micrographs and energy-dispersive X-ray spectroscopy (EDX) provide a vivid layout of K and its on-spot composition, respectively, deducing that a well-dispersed K ion promotion exists inside brucite-like layers. Experimental results carried out by a thermogravimetric analyzer (TGA) show striking CO2 capacity up to 1.93 mmol g(-1) at 300 degrees C, 1.7 times higher than that of a conventional K2CO3-promoted hydrotalcite adsorbent (1.11 mmol g(-1)), and fast adsorption kinetics for this precursor.