Tailoring the Oxygen Reduction Activity of Hemoglobin through Immobilization within Microporous Organic Polymer–Graphene Composite

Abstract

A facile one-pot, bottom-up approach to construct composite materials of graphene and a pyrimidine-based porous-organic polymer (PyPOP), as host for immobilizing human hemoglobin (Hb) biofunctional molecules, is reported. The graphene was selected because of its excellent electrical conductivity, while the PyPOP was utilized because of its pronounced permanent microporosity and chemical functionality. This approach enabled enclathration of the hemoglobin within the microporous composite through a ship-in-a-bottle process, where the composite of the PyPOP@G was constructed from its molecular precursors, under mild reaction conditions. The composite-enclathrated Fe-protoporphyrin-IX demonstrated electrocatalytic activity toward oxygen reduction, as a functional metallocomplex, yet with a distinct microenvironment provided by the globin protein. This approach delineates a pathway for platform microporous functional solids, where fine-tuning of functionality is facilitated by judicious choice of the active host molecules or complexes, targeting specific application.

Exfoliation of amorphous phthalocyanine conjugated polymers into ultrathin nanosheets for highly efficient oxygen reduction

“…Meanwhile, hetero-assemblies of 2D nanolayers such as transition metal dichalcogenides/diseleniums, 46 layered double hydroxides, 47 and metal-organic frameworks 48 with various graphene NSs (including graphene, nitrogen doped graphene, and defective graphene) have been recently received increasing interest in fabricating versatile high performance electrocatalysts including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) catalysts. The high activity is due to the combination of the highly exposed active centers presented on 2D nanolayers [27][28][29][30] and high electron transfer capability of graphene NSs [49][50][51][52] together with strong interaction between these components to reform the electronic distribution. Thanks to the ultrathin nature, the as-prepared bimetallic Fe0.5Co0.5Pc-CP NSs were used to fabricate a heterostructure Fe0.5Co0.5Pc-CP NS@G with graphene NSs, which exhibits high ORR catalytic activity in an alkaline medium.…”

Electrolytic Conversion of Sacrificial Metal–Organic Framework Thin Films into an Electrocatalytically Active Monolithic Oxide Coating for the Oxygen‐Evolution Reaction

“…For gas storage applications the conventional form of MOFs, powders, is well suited, for other applications molecularly uniform thin films of such extended networks rigidly attached to solid substrates are needed . Several techniques have been developed to fabricate such coatings on substrates of different materials, including metals, semiconductors, as well as metal oxides . Herein, we demonstrate the utilization of thin film, surface‐anchored metal–organic frameworks (SURMOFs) fabricated by a layer‐by‐layer process, are an excellent starting material to produce electrode‐supported electrochemical catalysts via electrode electrochemical restructuring process.…”

Microporous Solids En Route to Heterogeneous Electrocatalysis: The Oxygen Reduction Reaction

“…Recently, our group reported a one‐pot approach to construct a novel ternary system of a microporous pyrimidine‐based POP (PyPOP) composited with graphene (PyPOP@G) along with hemoglobin (Hb) immobilized within the composite matrix (PyPOP–Hb@G) . Inclusion of Hb in the composite slightly decreased the BET surface area (445 m 2 g −1 compared with 664 and 582 m 2 g −1 for PyPOP and PyPOP@G, respectively), yet maintained high porosity.…”

“…CVs collected on a RDE maintained at 1600 rpm, with a scan rate of 10 mV s −1 in O 2 ‐saturated 0.1 m KOH. Reproduced with permission . Copyright 2017, American Chemical Society.…”