Investigation on multifunctional Au/TiO2@n-octadecane microcapsules towards catalytic photoreforming hydrogen production and photothermal conversion

Abstract

Combining solar energy utilization and hydrogen production is an ideal model for renewable energy development. Especially the conversion of broad-spectrum solar energy into chemical energy of hydrogen and thermal energy can enrich solar energy storage methods. Herein, novel multifunctional Au/TiO2@n-octadecane microcapsules with core-shell structure were design and synthesized by wet chemical reduction and electrostatic adsorption self-assembly methods for photothermal hydrogen production and thermal storage. The results showed that microencapsulation of photothermal catalysts could provide an effective reaction area and excellent dispersion stability, where hydrogen production and light to hydrogen efficiency were increased in the 43% and 0.3% respectively, compared to the nanoparticle suspension system. Based on the recorded temperature variations caused by the photothermal effect, the calculated photothermal conversion efficiency and specific absorption rate of Au/TiO2@n-octadecane was 25.01% and 277% higher than that of Au/TiO2 suspension. The proposed hydrogen production and thermal storage method via multifunctional microcapsules might shed some light on the study of improving full-spectrum energy conversion efficiency of solar energy.