Bioinspired motifs in proton and CO₂ reduction with 3d-metal polypyridine complexes

Abstract

Mechanistic analysis of catalysis of the hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR) by polypyridine complexes of first-row transition metals highlights many similarities with the active sites of Natural enzymes.

Manipulating the Coordination Structure of Molecular Cobalt Sites in Periodic Mesoporous Organosilica for CO2 Photoreduction

“…Since polypyridyl complexes of Co and Ni are well-known CO 2 reduction catalysts, − the four MN x -PMOs with distinct isolated single sites (CoN 4 -PMO, CoN 5 -PMO, NiN 4 -PMO, and NiN 5 -PMO) were initially screened for photocatalytic CO 2 reduction in the presence of [Ru-PS] and TEOA donor. In a typical experiment 1 mg of MN x -PMO was dispersed in a CH 3 CN/TEOA (9:1) mixture containing the photosensitizer, purged with CO 2 to saturate the colloidal suspension, and irradiated under UV-filtered simulated solar light (λ > 400 nm, 100 mW cm –2 , AM 1.5G).…”

Manipulating the Coordination Structure of Molecular Cobalt Sites in Periodic Mesoporous Organosilica for CO2 Photoreduction

“…Since polypyridyl complexes of Co and Ni are well-known CO2 reduction catalysts, [52][53][54][55][56][57] the four MNx-PMOs with distinct isolated single-sites (CoN4-PMO, CoN5-PMO, NiN4-PMO and NiN5-PMO) were initially screened for photocatalytic CO2 reduction in the presence of [Ru-PS] and TEOA donor. In a typical experiment 1 mg MNx-PMO was dispersed in a CH3CN : TEOA (9 : 1) mixture containing the photosensitiser, purged with CO2 to saturate the colloidal suspension, and irradiated under UV-filtered simulated solar light (λ > 400 nm, 100 mW cm −2 , AM 1.5G).…”

Electrocatalytic Reduction of CO2 to CO by Molecular Cobalt–Polypyridine Diamine Complexes

“…The transformation of carbon dioxide (CO 2 ) to fuels and commodity chemicals is one of the most attractive methods to satisfy the energy demand and decrease atmospheric CO 2 levels [1,2]. Electrochemical reduction of CO 2 provides a sustainable approach to achieve this goal [3][4][5][6]. However, the electrochemical conversion of CO 2 often faces challenges due to the inherent stability of CO 2 , which hinders efficient implementation [7,8].…”

“…Early studies have focused on low-valent rare metal catalysts (e.g., Re [11,12], Ru [13,14], Ir [15], Rh [16,17]) and have been more recently extended to earth-abundant transition metal catalysts (e.g., Mn [18][19][20][21][22], Fe [8,[23][24][25], Ni [26,27], Co [28][29][30][31][32][33]). Among those developments, the cobalt complexes, coordinated with ligands such as porphyrin, cyclam, bipyridyl-N-heterocyclic carbene, polypyridines, and aminopyridines, have exhib-ited promising results in CO 2 reduction, owing to their abundant redox performance and the configurational flexibility provided by these ligands [4,6,34].…”

“…Catalytic activity has also been observed with other cobalt-porphyrin catalysts, but the products were not identified [28,35,37]. Several other tetraaza-macrocycles related to cobalt cyclams have shown promise as CO 2 reduction catalyst [4,6]. Gangi et al reported that a cobalt complex with the macrocycle 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene exhibits a strong positive shift in the Co ll/l reduction potential in the presence of CO 2 and has an equilibrium constant of 7 × 10 4 for CO 2 binding [38].…”