C2H4, He balance). This C2H4/C2H2 mixture represents a typical industrially relevant ethylene feed, and a highly selective catalyst is required to avoid over-hydrogenation to C2H6. The performance of our system under industrially relevant mixture conditions is shown in Figure . Not only does our system reduce the C2H2 concentration from 10,000 ppm to undetectable levels without any observed over-hydrogenation to C2H6 (Figure , and Figure ), it does so in less than one hour (50 minutes), which is a 30-and 100-fold improvement over our recently investigated Coporphyrin (28 hours) or Co-PCN-222 system (87 hours), respectively. Interestingly, the [Co(dmgH)2pyCl]-based system efficiently and selectively reduces the C2H2 concentration from 10,000 ppm to undetectable levels with 99.8% ethylene selectivity over ethane even in the presence of 99% C2H4 (1 vol.% C2H2, 99 vol.% C2H4, He balance), and it does so in half an hour ( minutes) (Figure ). Importantly, the calculated production efficiency of our system is ∼13 L g -1 h -1 (liters of ethylene produced over gram of catalyst per hour), which is a factor of ∼7 higher than the previously investigated homogeneous batch Co-porphyrin system. Our batch-based production efficiency exceeds the industrial demand of >10 L g -1 h -1 , making its industrial implementation promising and could be even further improved in a flow photochemical set-up. The excellent performance of our system under the industrially relevant conditions allows for its re-use. The same catalyst solution can be purged with fresh C2H4/C2H2 mixture up to three times before losing its ability to reduce all C2H2 in the headspace to C2H4 (Figure ), most likely due to its low structural stability that is caused by the fragile ligand framework around the Co center where the individual oximes are only held together by weak hydrogen bonding (Figure and S9).