Efficient Electrocatalytic Proton Reduction with Carbon Nanotube-Supported Metal-Organic Frameworks

Hydrogen production from Earth-abundant catalysts remains an important but difficult challenge. Here we report the growth of Hf₁₂-porphyrin metal-organic frameworks (MOFs) on carbon nanotubes (CNTs) for electrocatalytic proton reduction. Covalent attachment of MOF nanoplates to conductive CNTs improves electron transfer from the electrode to Co-porphyrin active sites, which leads to effective proton reduction via protonation of a Co^I-H intermediate. The Hf₁₂-CoDBP/CNT assembly afforded a turnover number of 32 000 in 30 min with a turnover frequency of 17.7 S^-1, placing it among the most active Co-based molecular electrocatalysts.