Covalent Organic
Framework Films through Electrophoretic
DepositionCreating Efficient Morphologies for Catalysis
Julian
M. Rotter
Simon Weinberger
Jonathan Kampmann
Torben Sick
Menny Shalom
Thomas Bein
Dana D. Medina
10.1021/acs.chemmater.9b02286.s001
https://acs.figshare.com/articles/journal_contribution/Covalent_Organic_Framework_Films_through_Electrophoretic_Deposition_Creating_Efficient_Morphologies_for_Catalysis/11307185
The ability to grow covalent organic framework (COF)
films allows
for studying their properties as solid layers and enables the incorporation
of these materials into a variety of functional devices. Here, we
report on the fabrication of COF films and coatings by electrophoretic
deposition (EPD). We demonstrate that the EPD technique is suitable
for depositing COFs featuring two- and three-dimensional structures
linked by imine or boronate ester bonds, namely, BDT-ETTA COF, COF-300,
and COF-5. For the deposition, COF nanoparticle suspensions are prepared
by dispersing the as-synthesized bulk materials in solvents with low
dielectric constants. Subsequently, two electrodes are immersed into
the COF particle suspensions, and upon inducing electric fields ranging
from 100 to 900 V cm<sup>–1</sup>, COFs are deposited as films
on the positively charged electrode. Through EPD, within 2 min, large-area
films of up to 25 cm<sup>2</sup> are obtained on smooth or corrugated
surfaces. COF films prepared by EPD feature an inherent textural porosity
and tunable thickness, demonstrated from 400 nm to 24 μm. By
controlling the deposition parameters such as duration, particle concentration,
and applied potential, deposits of precise thickness can be produced.
Furthermore, codepositions of different COFs as well as COF/Pt nanoparticles from
mixed suspensions are demonstrated. The film morphologies obtained
by EPD are shown to be advantageous for catalysis, as demonstrated
for sacrificial agent-free photoelectrochemical water reduction. Here,
BDT-ETTA COF photocathodes show a strongly increased photocurrent
density compared to the respective dense and oriented films. Typical
BDT-ETTA COF/Pt nanoparticle hybrid films exhibit photocurrent densities
of over 100 μA cm<sup>–2</sup>. The rapid and scalable
deposition of COF particles as films and coatings through EPD is a
versatile addition to the toolbox of COF film fabrication techniques,
allowing for tailoring COF film architectures for desired
functionalities.
2019-12-02 22:43:26
BDT-ETTA COF photocathodes show
boronate ester bonds
COF particle suspensions
EPD
COF films
as-synthesized bulk materials
Covalent Organic Framework Films
films exhibit photocurrent densities
24 μ m
COF film architectures
COF film fabrication techniques
agent-free photoelectrochemical water reduction
25 cm 2
COF nanoparticle suspensions