Non-covalent assembly of proton donors and p-benzoquinone anions for co-electrocatalytic reduction of dioxygen

Abstract

The two-electron and two-proton p-hydroquinone/p-benzoquinone (H2Q/BQ) redox couple has mechanistic parallels to the function of ubiquinone in the electron transport chain. This proton-dependent redox behavior has shown applicability in catalytic...

Chemical and Electrochemical O2 Reduction on Earth-Abundant M-N-C Catalysts and Implications for Mediated Electrolysis

“…The aromatic HQ1 structure should enable physisorption without blocking CoN x O 2 binding sites, and the favorable HQ1 binding will ensure that HQ1 will be available to participate directly in O 2 reduction (Scheme a). The kinetic data presented above are consistent with a mechanism that closely resembles hydroquinone-mediated O 2 reduction with a molecular Co-salophen complex (Scheme b). , Similar HAT-mediated O 2 reduction mechanisms have been observed with other molecular catalysts (Fe-porphyrins with pendent quinol groups and a Mn-salophen complex with cocatalytic hydroquinone), in addition to enzymatic reactions with O 2 …”

Catalytic Reduction of Dioxygen to Water by a Bioinspired Non-Heme Iron Complex via a 2+2 Mechanism

“…Platinum has traditionally been the best catalyst for the ORR, but due to its high cost and limited reserves, low-cost and earth-abundant transition metal catalysts are needed . Stemming from continuous efforts to mimic biological active sites for O 2 storage, transport, and activation, macrocyclic N 4 complexes with iron, , cobalt, , and manganese , active sites have been studied extensively as molecular catalysts for the ORR. ,− Non-macrocyclic ligand frameworks have been relatively less explored, with limited reports on cobalt-, , copper-, , and manganese-based − systems . To the best of our knowledge, there has only been one previously reported homogeneous non-macrocyclic iron system shown to be a competent catalyst for the ORR .…”

Inverse potential scaling in co-electrocatalytic activity for CO2reduction through redox mediator tuning and catalyst design

“…10 Co-catalytic systems which utilize RMs have been successfully developed for homogeneous O 2 reduction, increasing the overall activity of the system and shifting the selectivity of the reaction. [11][12][13] In these homogeneous systems, RMs deliver redox equivalents to the catalyst active sites with greater mobility than is possible in biological systems. Parallel developments have enabled electrocatalytic N 2 reduction, where weak C-H bonds are generated in a metallocene-based RM to assist in the cleavage of inert bonds, 14 and alcohol oxidation, where RMs are utilized to facilitate hydrogen atom transfer processes that work in conjunction with the catalyst.…”