Voltammetric and spectroscopic characterization of early intermediates in the Co(ii)–polypyridyl-catalyzed reduction of water

Abstract

Early intermediates of catalytic water reduction by a Co(II)-polypyridyl species have been characterized. Electrochemical detection of the Co(III)-hydride and time-resolved spectroscopic detection of the Co(I)-ligand intermediates provide an understanding of their reactivity in electrolytic or light-driven reduction of protons to hydrogen.

Mononuclear Iron Complexes with Tetraazadentate Ligands as Water Oxidation Catalysts

“…Synthesis: Fe(CF 3 SO 3 ) 2 (CH 3 CN) 2 was prepared in dry acetonitrile following a literature procedure and stored under inert atmosphere. The synthesis of ligand 2 have been reported previously …”

Electrochemical Detection of Transient Cobalt Hydride Intermediates of Electrocatalytic Hydrogen Production

“…[1][2][3][4][5][6] Many cobalt catalysts display desirable catalytic properties, including low overpotential, [7][8][9][10][11] solubility in water, 10,[12][13][14][15][16][17][18][19][20][21][22] and stability towards O2. [23][24][25][26] Several groups have constructed hybrid systems for production of H2 in which a molecular cobalt catalyst has been attached to an electrode surface, [27][28][29][30][31] covalently linked to a photosensitizer, [32][33][34][35][36] or inserted into Photosystem I.…”

Photo-induced redox catalysis for proton reduction to hydrogen with homogeneous molecular systems using rhodium-based catalysts

“…Some of these homogeneous photocatalytic systems can operate very efficiently (in terms of number of catalytic cycles or turnover number (TON)) in organic or mixed aqueous-organic solvents. Those reaching a turnover number versus catalyst (TON Cat ) above 100 in fully aqueous solution were rare and limited to rhodium [36][37][38][39] and platinum [40] but, since two years, several examples with cobalt [41][42][43][44][45][46][47][48][49][50][51][52][53][54], iron [55][56][57][58] nickel [59] were reported. Developing H 2 -evolving photocatalytic systems functioning in pure water is essential for their coupling with water oxidation systems in photoelectrochemical water-splitting devices.…”