Polymer Modification of Surface Electronic Properties of Electrocatalysts

Abstract

Finding alternative ways to tailor the electronic properties of a catalyst to actively and selectively drive reactions of interest has been a growing research topic in the field of electrochemistry. In this Letter, we investigate the tuning of the surface electronic properties of electrocatalysts via polymer modification. We show that when a nickel oxide water oxidation catalyst is coated with polytetrafluoroethylene, stable Ni–CF x bonds are introduced at the nickel oxide/polymer interface, resulting in shifting of the reaction selectivity away from the oxygen evolution reaction and toward hydrogen peroxide formation. It is shown that the electron-withdrawing character of the surface fluorocarbon molecule leaves a slight positive charge on the water oxidation intermediates at the adjacent active nickel sites, making their bonds weaker. The concept of modifying the surface electronic properties of an electrocatalyst via stable polymer modification offers an additional route to tune multipathway reactions in polymer/electrocatalyst environments, like with ionomer-modified catalysts or with membrane electrode assemblies.

Fluorine-containing nano-objects with the same compositions but different segment distributions: synthesis, characterization and comparison

“…2,6 Correspondingly, fluoropolymers are indispensable in modern industry and play an important role in the automotive industry, 7 aerospace, 8,9 construction, 10 high-end equipment manufacturing, electronic information, and new energy strategies. [11][12][13] However, due to the high incompatibility of fluoropolymers with other polymers, the practical application of fluoropolymers is limited. Most of the applications of fluoropolymers are closely related to a self-assembly process.…”

Interfacial stress induced by the adaptive construction of hydrangea-like heterojunctions based on in situ electrochemical phase reconfiguration for highly efficient oxygen evolution reaction at high current density

“…Designing high-performance and cost-effective catalysts for the oxygen evolution reaction (OER) to develop electrochemical conversion technologies such as N 2 reduction, 1 CO/CO 2 reduction 2 and water splitting 3 is of great significance to the current world-advocated zero-carbon emission scheme. Among varied OER catalysts, nickel-based catalysts with a d-electron configuration consisting of low-cost and earth-abundant components including oxides/hydroxides, 4 phosphides, 5 nitrides 6 and chalcogenides 7 exhibit impressive OER activity, and are promising to replace noble metal oxides such as IrO 2 and RuO 2 . However, the further improvement of their activity is restricted by the limited active sites and electronic structure.…”

Self-Photocatalytic Splitting of Carbon Dioxide Using Co-cationic Perovskite Nanocrystals in the Absence of Water

“…The surface-bound hydroxyls, 30,31 generated from reduction channels to be discussed, can accept two holes and release a proton to form a bound oxygen cation. 30 This cation can either take a water and release a proton (not shown) 30 or directly take a hydroxyl anion (either free OH− or a bound OH nearby) to form a surface-bound peroxide species; 30 it eventually takes another two holes and releases another proton to form an oxygen molecule, leaving a for the PeNC to accept CO 2 for further reduction. For the reduction path, the formation of bound dioxycarbon anion (Pb−OCO − ) is expected as the first step to initiate CO 2 reduction; evolution of two bands, indicated with dashed lines (v), represents formation of the dioxycarbon anion 32,33 through electron transfer from PeNC to CO 2 .…”

“…Another channel as oxidation path is shown in Figure b. The surface-bound hydroxyls, , generated from reduction channels to be discussed, can accept two holes and release a proton to form a bound oxygen cation . This cation can either take a water and release a proton (not shown) or directly take a hydroxyl anion (either free OH– or a bound OH nearby) to form a surface-bound peroxide species; it eventually takes another two holes and releases another proton to form an oxygen molecule, leaving a vacancy for the PeNC to accept CO 2 for further reduction.…”