Boosting visible-light-driven hydrogen evolution of covalent organic frameworks through compositing with MoS₂: a promising candidate for noble-metal-free photocatalysts

Abstract

A series of ultrathin MoS2 nanosheet decorated ketoenamine-based COF (TpPa-1) photocatalysts show excellent photocatalytic activity under visible light irradiation without noble-metal co-catalysts.

Rational Design and Application of Covalent Organic Frameworks for Solar Fuel Production

“…In general, COF based photocatalysts are used in conjunction with noble metal nanoparticles (NPs) as a cocatalysts to reduce the recombination rate of photogenerated charge carriers. Zhang et al reported the ketoenamine-based covalent organic framework combination with non-noble metal MoS 2 for the first time in 2019 in order to find an alternative to scarce and expensive noble metal NPs [ 53 ]. An exfoliated MoS 2 dispersion of N,N -dimethylformamide (DMF) was used for the in situ growth of TpPa-1-COF to form a MoS 2 /TpPa-1-COF composite material.…”

Light-Driven Hydrogen Evolution Assisted by Covalent Organic Frameworks

“…In addition, two very interesting systems that do not need a Pt co-catalyst to be significantly active emerge from the combination of hexagonal hematite (α-Fe 2 O 3 ) nanosheets on top of the honeycomb-like β-ketoenamine linked TpPa-2-COF generated from reaction of TP with 2,5-dimethyl-p-phenylenediamine (Pa-2) (Figure 3) [52], rendering 3.8 mmol H 2 •g −1 •h −1 ; and from the in situ growth of the TpPa-1-COF in exfoliated MoS 2 , generating a hybrid system where MoS 2 is deposited on top of the TpPa-1-COF [53]. Other possibilities include the deposition of CdS NPs on top COFs, such as the TpPa-2-COF [54] or the CTF-1-COF [55]; and the use of TiO 2 nanosheets functionalized with 3-aminopropyltriethoxysilane (APTES) to chemically bind TpPa-1-COF onto its surface by imine bond formation [56], yielding 11.2 mmol H 2 •g −1 •h −1 and an AQE of 7.6% at 420 nm in the presence of Pt.…”

“…As stated before, only a few COFs have shown significant photochemical activity in the HER without the need to add a metal-based co-catalyst [18,27,28,52,53]. Among the different transition metals able to promote the HER, until now very few works have used a metal co-catalyst other than Pt either in the molecular form or as NPs.…”

Two‐Dimensional Covalent‐Organic Frameworks for Photocatalysis: The Critical Roles of Building Block and Linkage

“…[ 91 ] The composite, MoS 2 /TpPa‐1‐COF (3%wt MoS 2 ), displayed a high hydrogen production rate of 5585 μmol g −1 h −1 in the absence of Pt. [ 92 ] In addition, a series of Z‐scheme heterojunction based on 2D COFs were also reported and displayed outstanding HER performance. For instance, α‐Fe 2 O 3 /TpPa‐2‐COF (the weight ratio of α‐Fe 2 O 3 : TpPa‐2‐COF = 3:7), CdS‐COF (the weight ratio of CdS: COF = 90:10) exhibit high catalytic activities without noble metal co‐catalysts, showing a H 2 production rate of 3770 and 3678 μmol g −1 h −1 , respectively.…”