To deconvolute the nature of the CO2 consumption further, we now explicitely take the catalytic production rates of CO (𝑉 ̇𝐶𝑂 ) and H2 (𝑉 ̇𝐻2 ) as well as the CO2 input feed (𝑉 ̇𝐶𝑂 2 ,𝑖𝑛 ) and the exit flow rate (𝑉 ̇𝑜𝑢𝑡 ) into account. Starting from the gas volume and carbon balance (Supplemental Note 5, Supplementary Equations 9-19), we derive and define the experimentally accessible Carbon-Crossover-Coefficient (CCC) for the acid-base CO2 depletion as