Simultaneous electro-generation/polymerization of Cu nanocluster embedded conductive poly(2,2′:5′,2′′-terthiophene) films at micro and macro liquid/liquid interfaces

Abstract

Cu nanoparticles (NPs) have been shown to be excellent electrocatalysts, particularly for CO2 reduction – a critical reaction for sequestering anthropogenic, atmospheric carbon. Herein, the micro interface between two immiscible electrolyte solutions (ITIES) is exploited for the simultaneous electropolymerization of 2,2′:5′,2′′-terthiophene (TT) and reduction of Cu2+ to Cu nanoparticles (NPs) generating a flexible electrocatalytic composite electrode material. TT acts as an electron donor in 1,2-dichloroethane (DCE) through heterogeneous electron transfer across the water|DCE (w|DCE) interface to CuSO4 dissolved in water. The nanocomposite formation process was probed using cyclic voltammetry as well as electrochemical impedance spectroscopy (EIS). CV and EIS data show that the film forms quickly; however, the interfacial reaction is not spontaneous and does not proceed without an applied potential. At high [TT] the heterogeneous electron transfer wave was recorded voltammetrically but not at low [TT]. However, probing the edge of the polarizable potential window was found to be sufficient to initiate electrogeneration/electropolymerization. SEM and TEM were used to image and analyze the final Cu NP/poly-TT composites and it was discovered that there is a concomitant decrease in NP size with increasing [TT]. Preliminary electrocatalysis results at a nanocomposite modified large glassy carbon electrode saw a > 2 × increase in CO2 reduction currents versus an unmodified electrode. These data suggest that this strategy is a promising means of generating electrocatalytic materials for carbon capture. However, films electrosynthesized at a micro and ~ 1 mm ITIES demonstrated poor reusability.

Electrosynthesis of Au nanocluster embedded conductive polymer films at soft interfaces using dithiafulvenyl-functionalized pyrene

“…Owing to the high redox potential of AuCl 4 − , 39 the Au salt is likely reduced to Au 0 generating metal nanoparticles (NPs). This agrees well with our recent reports using ferrocene (Fc) 7 and TT 9,22 as organic phase electron donors, as well as Bai et al's electrosynthesis of Ag wire at a nanopipette interface. 40 The oxidation potential of 1 was determined by dissolving ∼1 mM of the monomer in DCE and recording the CV at a Pt inlaid disc ultramicroelectrode (UME), with a radius of 12.5 µm, and with the potential referenced to the ferrocene redox couple (Fc + /Fc) as described previously, 41 with E °′ Fc þ =Fc ¼ 0:64 V (vs. SHE).…”

“…Owing to the high redox potential of AuCl 4 − , , 39 the Au salt is likely reduced to Au 0 generating metal nanoparticles (NPs). This agrees well with our recent reports using ferrocene (Fc) 7 and TT 9,22 as organic phase electron donors, as well as Bai et al 's electrosynthesis of Ag wire at a nanopipette interface. 40…”

“…They were able to reproducibly electrogenerate films <50 nm thick that could be extracted from the interface, stored for long-term use, and were shown to be biocompatible. Then, our group demonstrated further synthetic control through miniaturization of the ITIES and building on the works for Cunnane and others with simultaneous Au 9 and Cu 22 NP generation and TT electropolymerization. This approach relied on performing the electrosynthesis at a micro-ITIES (25 μm in diameter), while installing the metal salt ( e.g.…”

In Situ Engineering of Conducting Polymer Nanocomposites at Liquid/Liquid Interfaces: A Perspective on Fundamentals to Technological Significance

“…47,48 Overall, the kinetics of interfacial charge transfer are regulated by the charges of the reactants, their location with respect to the interface, and the dielectric properties of the two immiscible phases forming the interface. 49 Driven by the inferences mentioned above, diverse parameters influence the growth mechanism of nanostructures during interfacial polymerization and offer a new platform for regulating polymer properties.…”

“…73 A concomitant electropolymerization of 2,2′:5′,2″-terthiophene (TT) and reduction of Cu 2+ to Cu nanoparticles at the micro interface between two immiscible electrolyte solutions could develop a flexible electrocatalytic composite. 49 The Cu/polyTT composite modified glassy carbon electrode testified to be a promising carbon capture material. Furthermore, a series of surface active pyrrole derivatives were interfacially polymerized by an electron transfer between a monomer dissolved in the organic phase and Ce(SO) 4 in the aqueous phase.…”