Regarding the by-products and unreacted reactants at the reactor outlet Figure illustrates the molar flow rate of CO and CO2 plotted against the H2/CO2 inlet ratio. Both, the CO2 and the CO outlet molar flow rates decrease with increasing 𝑟 in and reach zero asymptotically. The decrease in CO2 flow rate is associated with an increasing conversion, while the decrease in CO flow rate indicates a rising CH4 selectivity. Both values, conversion and selectivity, approach 100% for high values of 𝑟 in (compare Figure and A3 in the SI for methane selectivity), which can be attributed to the fact that CH4 formation is favoured thermodynamically as the H2/CO2 ratio increases . Consequently, higher H2/CO2 ratios are beneficial for the subsequent CH4 purification steps, due to smaller impurity amounts. This leads to a decreased equipment size and/or energy demand for methane purification.