A Supramolecular Porous Organic Cage Platform Promotes Electrochemical Hydrogen Evolution from Water Catalyzed by Cobalt Porphyrins

Abstract

We report a supramolecular porous organic cage platform composed of cobalt porphyrins for catalyzing the electrochemical hydrogen evolution reaction (HER) from water at neutral pH. Owing to its permanent porosity, the supramolecular structure yields a catalyst film with a fivefold increase in the number of electrochemically active cobalt atoms and an improvement in Tafel slope from 170 mV/decade to 119 mV/decade compared to a planar cobalt porphyrin analog, reaching activities over 19,000 turnovers for HER over a 24-hour period with 100 % Faradaic efficiency.

Supramolecular Framework-Driven Electrical Conductivities and Hydrogen Evolution Activities of Hybrid Nickel(II)–Cerium(IV) Complex Salts Cooperativity

“…Therefore, conductivity cast some superiorities to accomplish enhanced electrocatalytic performance. The enhancing HER activity imputed to its electrical conductivity of heterogeneous catalyst is well reported by renowned scientific groups like Sun et al, Chen et al, Wang et al, and Chhowalla et al − The supramolecular architecture contributes to both chemical and electrochemical stability, − heterogenized electrode assembly driven by the supramolecular framework accelerates the facile charge, and substrate transport strengthens HER performance. − It is well documented, owing to the supramolecular architecture of the crystalline complex accounting for the facile delivery of proton and electron than the monomeric counterpart. So, the supramolecular architecture-induced charge transport properties well corroborate the hydrogen evolution activity.…”

Electrocatalytic production of hydrogen peroxide enabled by post-synthetic modification of a self-assembled porphyrin cube

“…24–27 Literature reports of covalently synthesized cubic multinuclear catalysts applied to ORR and other small molecule activations encouraged our efforts to develop self-assembled catalysts with different topologies. 13,28,29 We have used a subcomponent self-assembly route to synthesize porphyrin-based cubes with tris chelated vertices reported by Nitschke (see Fig. 2).…”

CO2 to CO Electroreduction, Electrocatalytic H2 Evolution, and Catalytic Degradation of Organic Dyes Using a Co(II) meso-Tetraarylporphyrin

“…Moreover, there are one or two axial positions available for binding small molecules [ 10 , 11 , 12 , 26 , 27 , 28 , 29 ]. Both properties make Co porphyrins very suitable for redox catalysis [ 22 , 23 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ].…”

“…In view of the climate crisis, the photochemical or electrochemical conversion of CO 2 and H 2 O into energy-rich fuel products such as methanol [ 30 , 32 , 33 ] or dihydrogen (H 2 ) [ 45 , 46 , 47 ] are important goals, and cobalt porphyrin complexes have been studied as catalysts for the CO 2 reduction [ 30 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 44 ] and the H 2 evolution [ 18 , 41 , 42 , 48 ], besides other important redox processes such as O 2 reduction [ 19 , 23 , 49 , 50 , 51 , 52 , 53 , 54 ], O 2 evolution reaction (OER) [ 49 , 55 ], and interesting organic redox transformations [ 56 , 57 , 58 , 59 , 60 ].…”

“…Electrochemical hydrogen production suffers from a huge overpotential of the so-called hydrogen evolution reaction (HER) for many materials, and elemental platinum was the first choice for a long time [ 45 , 46 , 47 ]. In the quest to replace this expensive metal and create molecular redox catalysts allowing the operation of cheaper electrode materials, complexes of abundant transition metals [ 47 , 65 , 66 , 67 , 68 ] containing various ligands including Co porphyrins have been synthesised [ 18 , 41 , 45 , 47 , 48 , 56 , 66 , 67 , 68 , 69 , 70 ]. For example, in a benchmarking work, the so-called hangman porphyrin which contains a proton-transferring COOH group in close proximity to the Co centre allowed very efficient HER catalysis with PhCOOH as substrate at a proton transfer (PT) rate of 3.10 −6 s −1 and an electron transfer (ET) rate constant of 8.5 10 −6 s −1 [ 69 ].…”