Synthesis, characterization and high temperature CO2 capture capacity of nanoscale Ca-based layered double hydroxides via reverse microemulsion

•High stable homogeneous suspensions containing dispersed Ca-Al layered double hydroxide (LDH) nanoparticles was developed by a reverse microemulsion method.•The Ca-Al LDH nanoparticles with different structural morphology was developed from amorphous aggregation to platelet, regular hexagon and hydrangea-like hierarchical structure by controlling the concentration, reaction time and temperature.•The calcined nano-sized Cal-Al LDH powders display excellent CO2 capture behavior at 600°C and exhibits a faster rate of CO2 absorption and higher CO2 capture capacity of 44 wt% CO2 with synthesized at 80°C. In this study, we report a reverse microemulsion method to prepare stable homogeneous suspensions containing dispersed Ca–Al layered double hydroxide (LDH) nanoparticles. By changing the concentration, reaction time and temperature, the nano-particles with different structural morphology was developed from amorphous aggregation to platelet, regular hexagon and hydrangea-like hierarchical structure. The crystallization and growth of Ca–Al LDH nanoparticles were involved with a nucleation and growth process under nonaqueous polar solvent/surfactant system. After calcination at 700°C, the calcined nano-sized Cal–Al LDH powders synthesized from the reverse microemulsion display remarkable CO2 capture behavior at 600°C, which is strongly dependent on the reaction conditions (concentration, time and temperature). The calcined powder synthesized at 80°C exhibits a faster rate of CO2 absorption and higher CO2 capture capacity of 44wt% CO2 without apparent degradation under multiple cycles of carbonation–calcination.