The cycloaddition of CO2 depends on several parameters. The catalytic performance can be improved via the addition of a co-catalyst, e.g., TBAB , or gold (Au) . Co-catalysts such as n-Bu4NBr (TBAB), n-Pr4NBr, n-Pr4NBr, Me4NBr showed a carbonate yields of 91%, 68%, 33%, and 6%, respectively, using hollow-structured Zn-Co based ZIF . The catalytic performance of these co-catalysts can be ordered in the sequence of nBu4N + >n-Pr4N + >Et4N + >Me4N + . The high performance of TBAB is due to the low interaction between nBu4N + and Br -.