Theory-guided design of hydrogen-bonded cobaltoporphyrin frameworks for highly selective electrochemical H2O2 production in acid

The pursuit of selective two-electron oxygen reduction reaction to H2O2 in acids is demanding and largely hampered by the lack of efficient non-precious-metal-based electrocatalysts. Metal macrocycles hold promise, but have been relatively underexplored. Efforts are called for to promote their inherent catalytic activities and/or increase the surface exposure of active sites. In this contribution, we perform the high-throughput computational screening of thirty-two different metalloporphyrins by comparing their adsorption free energies towards key reaction intermediates. Cobalt porphyrin is revealed to be the optimal candidate with a theoretical overpotential as small as 40 mV. Guided by the computational predictions, we prepare hydrogen-bonded cobaltoporphyrin frameworks in order to promote the solution accessibility of catalytically active sites for H2O2 production in acids. The product features an onset potential at similar to 0.68 V, H2O2 selectivity of >90%, turnover frequency of 10.9 s(-1) at 0.55 V and stability of similar to 30 h, the combination of which clearly renders it stand out from existing competitors for this challenging reaction.

Automated summary

The pursuit of selective two-electron oxygen reduction reaction to H2O2 in acids is challenging due to the lack of efficient non-precious-metal-based electrocatalysts. In this study, cobalt porphyrin is identified as the optimal candidate for this reaction. By preparing hydrogen-bonded cobaltoporphyrin frameworks, the solution accessibility of active sites is promoted, leading to excellent catalytic performance. The findings of this study offer new insights for the development of efficient electrocatalysts for the selective reduction of H2O2.