To improve the carbon dioxide (CO2) absorption performance of lithium orthosilicate (Li4SiO4), tablet-like Li4Si1-x Ti (x) O-4 and Li3.9Na0.1Si0.96Ti0.04O4 sorbents with loose and porous texture were prepared by a sol-gel process. The relationship between the Ti doping and volume expansion was studied for the first time. The results indicated that the Ti presence into the Li4SiO4 structure inhibited the growth of grains and abated the volume expansion. The X-ray diffraction and scanning electron microscopy results showed that the loose and porous solid solutions with similar phase crystallite but different grain sizes could obtain by heat treatment of precursor at 700 A degrees C. The optimum Ti content of Li4Si1-x Ti (x) O-4 seems to be 0.04 of Li4Si0.96Ti0.04O4. And the CO2 capture behaviors of Li3.9Na0.1Si0.96Ti0.04O4 were better than Li4Si0.96Ti0.04O4.