Effect of raw material sources on activated carbon catalytic activity for HI decomposition in the sulfur-iodine thermochemical cycle for hydrogen production

•Five activated carbons generated by steam activation of various raw materials.•Disclosing the relation between sample properties and catalytic activities.•Recommending AC-CS as a high-activity and stable catalyst in decomposing HI.

In order to study the effect of raw material sources on the catalytic performance of activated carbon, five activated carbon samples generated by steam activation of various raw materials (wood, coal, shell, bamboo and coconut shell) were investigated for their catalytic performance in HI decomposition for the sulfur–iodine (SI) thermochemical cycle. Their catalytic activities were evaluated from 573 K to 823 K. XRD, BET, SEM, proximate and ultimate analyses were used to characterize the catalysts. The results showed the raw materials of activated carbon played an important role in the catalytic activity of the activated carbon sample in HI decomposition. AC-CS and AC-SHELL exhibited the highest activity, followed by AC-BAMBOO, AC-COAL and AC-WOOD. AC-CS had the highest carbon content and the lowest ash content of the activated carbon samples. The catalytic activity of the activated carbon samples increased in coordination with increasing fixed carbon content and decreasing ash content. A long-term evaluation of catalytic performance was performed with AC-CS to assess its stability during extended use as an HI decomposition catalyst.