Cobalt Triphenylenehexaselenolate Metal−Organic Frameworks for Efficient Electrocatalytic Hydrogen Evolution

Nature achieves highly efficient water splitting through enzymes like [NiFeSe] hydrogenase, which exhibits superior oxygen tolerance and turnover rates compared to its [NiFe] counterparts. Inspired by the selenocysteine residues in the [NiFeSe] active site, we report the development of cobalt triphenylene-2,3,6,7,10,11-hexaselenolate (CoTHSe) metal−organic frameworks (MOFs) as electrocatalysts toward the hydrogen evolution reaction. While these materials exhibit catalytic overpotentials of 440−480 mV vs RHE, a Tafel slope of 62 mV/dec is observed for the air-exposed analog, demonstrating improved kinetic efficiency. Specifically, the CoTHSe variants achieve turnover frequencies of 770 and 611 h−1, significantly surpassing the 108 h−1 reported for the sulfur-based analog, CoTHT. Furthermore, the catalysts remain stable for over 18 h of electrolysis with near-unity Faradaic efficiency and no significant morphological degradation, highlighting the potential of selenium-coordinated MOFs for robust hydrogen evolution applications.