Electrocatalytic Properties of Binuclear Cu(II) Fused Porphyrins for Hydrogen Evolution

Binuclear copper­(II) porphyrins in which two copper­(II) porphyrin macrocycles are doubly fused at the meso-beta positions are shown to be active electrocatalysts for the hydrogen evolution reaction (2H+ + 2e– → H2). Structural characterization, including use of electron paramagnetic resonance and...

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Bibliographic Details
Published in:ACS catalysis Vol. 8; no. 10; pp. 9888 - 9898
Main Authors: Khusnutdinova, Diana, Wadsworth, Brian L, Flores, Marco, Beiler, Anna M, Reyes Cruz, Edgar A, Zenkov, Yegor, Moore, Gary F
Format: Journal Article
Language:English
Published: American Chemical Society 05-10-2018
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Summary:Binuclear copper­(II) porphyrins in which two copper­(II) porphyrin macrocycles are doubly fused at the meso-beta positions are shown to be active electrocatalysts for the hydrogen evolution reaction (2H+ + 2e– → H2). Structural characterization, including use of electron paramagnetic resonance and X-ray photoelectron spectroscopies, verifies the fused species contains two copper­(II) metal centers in its resting state. In comparison to the nonfused copper­(II) porphyrin complex, the fused species is reduced at significantly less applied bias potentials (ΔE 1/2 ∼ 570 mV for the first reduction process). Electrochemical characterization in the presence of substrate protons confirms the production of hydrogen with near-unity Faradaic efficiency, and kinetic analysis shows the catalyst achieves a maximum turnover frequency above 2 000 000 s–1. The enhancement in catalytic performance over analogous nonfused copper­(II) porphyrins indicates extended macrocycles provide an advantageous structural motif and design element for preparing electrocatalysts that activate small molecules of consequence to renewable energy.
ISSN:2155-5435
2155-5435
DOI:10.1021/acscatal.8b01776