Hydrogen Evolution of a Unique DNAzyme Composed of Cobalt‐Protoporphyrin IX and G‐Quadruplex DNA

Abstract Molecular hydrogen (H 2 ) is a clean and renewable fuel that has garnered significant interest in the search for alternatives to fossil fuels. Here, we constructed an artificial DNAzyme composed of cobalt‐protoporphyrin IX (CoPP) and G‐quadruplex DNA, possessing a unique H 2 O int ligand between the CoPP and G‐quartet planes. We show for the first time that CoPP‐DNAzyme catalyzes photo‐induced H 2 production under anaerobic conditions with a turnover number (TON) of 1229 ± 51 over 12 h at pH 6.05 and 10 °C. Compared with free‐CoPP, complexation with G‐quadruplex DNA resulted in a 4.7‐fold increase in H 2 production activity. The TON of the CoPP‐DNAzyme revealed an optimal acid‐base equilibrium with a p K a value of 7.60 ± 0.05, apparently originating from the equilibrium between Co(III)‐H − and Co(I) states. Our results demonstrate that the H 2 O int ligand can augment and modulate the intrinsic catalytic activity of H 2 production catalysts. These systems pave the way to using DNAzymes for H 2 evolution in the direct conversion of solar energy to H 2 from water.