title: Cobalt corrole catalyst for efficient hydrogen evolution reaction from H2O under ambient conditions: reactivity, spectroscopy, and density functional theory calculations.
abstract: The feasibility of a hydrogen-based economy relies very much on the availability of catalysts for the hydrogen evolution reaction (HER) that are not based on Pt or other noble elements. Significant breakthroughs have been achieved with certain first row transition metal complexes in terms of low overpotentials and large turnover rates, but the majority of reported work utilized purified and deoxygenated solvents (most commonly mixtures of organic solvents/acids). Realizing that the design of earth abundant metal catalysts that operate under truly ambient conditions remains an unresolved challenge, we have now developed an electronically tuned Co(III) corrole that can catalyze the HER from aqueous sulfuric acid at as low as -0.3 V vs NHE, with a turnover frequency of 600 s(-1) and ≫10(7) catalytic turnovers. Under aerobic conditions, using H2O from naturally available sources without any pretreatment, the same complex catalyzes the reduction of H(+) with a Faradaic Yield (FY) of 52%. Density functional theory (DFT) calculations indicate that the electron density on a putative hydride species is delocalized off from the H atom into the macrocycle. This makes the protonation of a [Co(III)-H](-) species the rate determining step (rds) for the HER consistent with the experimental data.
authors: Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata, India 700032.
authors: Biswajit
authors: B
authors: Mondal
authors: Kushal
authors: K
authors: Sengupta
authors: Atanu
authors: A
authors: Rana
authors: Atif
authors: A
authors: Mahammed
authors: Mark
authors: M
authors: Botoshansky
authors: Somdatta Ghosh
authors: SG
authors: Dey
authors: Zeev
authors: Z
authors: Gross
authors: Abhishek
authors: A
authors: Dey