Amine-Functionalized Graphene/CdS Composite for Photocatalytic Reduction of CO₂

Abstract

This study provides a significant enhancement in CO2 photoconversion efficiency by the functionalization of a reduced graphene oxide/cadmium sulfide composite (rGO/CdS) with amine. The amine-functionalized graphene/CdS composite (AG/CdS) was obtained in two steps. First, graphene oxide (GO) was selectively deposited via electrostatic interaction with CdS nanoparticles modified with 3-aminopropyltriethoxysilane. Subsequently, ethylenediamine (NH2C2H4NH2) was grafted by an N,N′-dicyclohexylcarbodiimide coupling reaction between the amine group of ethylenediamine and the carboxylic group of GO. As a result, a few layers of amine-functionalized graphene wrapped CdS uniformly, forming a large interfacial area. Under visible light, the photocurrent through the AG/CdS significantly increased because of enhanced charge separation in CdS. The CO2 adsorption capacity on AG/CdS was 4 times greater than that on rGO/CdS at 1 bar. These effects resulted in a methane formation rate of 2.84 μmol/(g h) under visible light and CO2 at 1 bar, corresponding to 3.5 times that observed for rGO/CdS. Interestingly, a high methane formation rate (1.62 μmol/(g h)) was observed for AG/CdS under CO2 at low pressure (0.1 bar), corresponding to a value 20 times greater than that observed for the rGO/CdS. Thus, the enhanced performance for photocatalytic reduction of CO2 on the AG/CdS is due to the improved CO2 adsorption related to the amine groups on amine-functionalized graphene, which sustains the strong absorption of visible light and superior charge-transfer properties in comparison with those of graphene.

In Situ‐Fabricated 2D/2D Heterojunctions of Ultrathin SiC/Reduced Graphene Oxide Nanosheets for Efficient CO2 Photoreduction with High CH4 Selectivity

“…The photocatalytic CO 2 reduction performance was evaluated in the presence of H 2 O vapor, involving a gas–solid heterogeneous reaction. CO and CH 4 were detected as the main products in our reaction system (Figure S2), in line with the previous reports using a similar method . The generation rates of CO, CH 4 , and active electrons are summarized in Figure a.…”

Atomic‐Level Reactive Sites for Semiconductor‐Based Photocatalytic CO2 Reduction

“…Cho et al developed amine‐functionalized reduced graphene oxide by an N , N ′‐dicyclohexylcarbodiimide coupling between the amine group of ethylenediamine and the carboxylic group of GO. The amine‐functionalized graphene (AG) wraps‐around the CdS nanoparticles to form the composite AG/CdS.…”

“…CO 2 photoreduction on CdS composites: a) photoreduction of CO 2 (1 bar) on AG/CdS with varying graphene content under visible light (>420 nm); b,c) CO 2 photoreduction and CH 4 /CO ratio on CdS, G/CdS, and Ag/CdS under b) CO 2 at 1 bar (40 °C) and c) low‐pressure CO 2 (0.1 bar, 40 °C); d) cyclic photoreduction of CO 2 on rGO/CdS and AG/CdS; e) illustration of proposed mechanism of CO 2 photoreduction on AG/CdS. Reproduced with permission . Copyright 2017, American Chemical Society.…”

Highly efficient charge transfer in CdS-covalent organic framework nanocomposites for stable photocatalytic hydrogen evolution under visible light

“…S9 online). The superior photocatalyitc performance over 20%CdS-CTF-1 is hypothesized to be largely dependent on the uniform and well-dispersed CdS nanoparticles on CTF-1 layers [52,53]. Unlike previously reported CdS-based photocatalysts, which suffered from either the deterioration of the supports' structure or the leaching of CdS nanoparticles, 20%CdS-CTF-1 showed higher stability during the photocatalytic reaction (Fig.…”