Besides the exploration of the cata

Besides the exploration of the catalyst with excellent performance,
the innovation of reactor and process technology is another
important aspect for obtaining the higher yield and better
selectivity toward methanol with the reducing proportion of byproducts
in CO2 hydrogenation. The methanol productivity is
usually low using the traditional on-stage catalyst bed in the fixedbed
gas phase tubular reactor. Rahimpour [41] proposed a twostage
catalyst bed concept for conversion of carbon dioxide into
methanol. Compared with a conventional single catalyst bed
system, two-stage bed system showed the extremely favorable
temperature profile along the reactor tube length, causing a higher
level of catalyst activity and a longer catalyst life time. Also,
favorable temperature profile of catalyst bed plus high level of
catalyst activity in gas-cooled reactor of two-stage bed system,
results in more production rate in this system. Other researchers
[29] employed a novel low-temperature route in a semi-bath
autoclave reactor for the efficient conversion of CO2 into methanol.
This process realized a very high catalytic activity of methanol