One-pot self-assembly of Cu2O/RGO composite aerogel for aqueous photocatalysis
Graphical abstract
Schematic formation process of Cu2O/RGO aerogel and its recycling processes.
Introduction
Semiconductor-based photocatalysis has been widely employed in the treatment of various environmental pollutants [1], [2], [3], [4], [5]. The incorporation of reduced graphene oxide (RGO) into semiconductor photocatalysts has been proved to be an effective strategy to improve their performance [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17]. The existence of suitable amount of functional groups on RGO surface ensures RGO to have intimate contact with the semiconductor photocatalysts, which helps to promote the separation of the photo-generated charge carriers in semiconductors [18]. However, the use of these RGO–semiconductor nanocomposites in aqueous photocatalytic systems meets with limitation since these powder materials are difficult to be separated from the reaction system [19], [20], [21], [22]. For practical applications, it is ideal to immobilize the nano-structured photocatalysts on certain solid surfaces for separation and recycling.
Recently, reduced graphene oxide (RGO)-based aerogels have attracted extensive attention and have shown a variety of applications due to their peculiar properties, including low density, high surface area, large open pores, as well as those translated from the RGO building block [23], [24], [25], [26], [27]. Our recent studies also demonstrated that RGO-based aerogel can be an ideal support for semiconductor photocatalysts due to its large specific surface area for enhanced adsorption toward pollutants, open pores for fast mass transportation, easy tuning of surface wettability for selective adsorption toward pollutants [28], [29], [30]. The most attractive of using RGO aerogels as support for photocatalysts lies in its extremely light weight, which enables it to float on the surface of the reaction system to absorb more solar irradiations [28], [29]. However, although RGO incorporated semiconductor photocatalysts have been well studied, the investigations on the formation of semiconductor/RGO composite aerogels with focus on their applications in photocatalysis is limited [28], [29].
Herein, we reported a facile one-pot hydrothermal method to synthesize Cu2O/RGO composite aerogel using glucose as a reducing agent and cross-linker. Cu2O, a p-type semiconductor with a band-gap of about 2.0 eV, has been used in water purification due to its appropriate band gap, non-toxicity and environmental compatibility [31], [32], [33]. By embedding Cu2O into RGO aerogel, the as-formed Cu2O/RGO composite aerogel shows excellent performance in the photocatalytic degradation of methyl orange (MO) under visible light. The photocatalyst can float on water, showing impressive performance in terms of its activity and stability and due to its macroscopic shape, it is capable of removing it with a tweezers and reusing it with unvaried performance.
Section snippets
Preparation
Graphene oxide (GO) was synthesized using a modified Hummers methods from graphite flake [34].
For preparation of Cu2O/RGO composite aerogel, GO aqueous dispersion (16.7 mL, 6 mg/mL) was sonicated in a 100 mL beaker for 1 h. Then 40 mL CuSO4·5H2O solution containing varied amount of CuSO4·5H2O (200, 400 and 600 mg) was added into GO aqueous dispersion under vigorous magnetic stirring. The pH value of the solution was adjusted to 10. After that, glucose (200 mg) was added under vigorous stirring. The
Results and discussion
The Cu2O/RGO aerogels were prepared from GO and CuSO4·5H2O hydrothermally using glucose as both reducing and cross-linking agent. Since our previous study on the formation of RGO aerogels revealed that RGO hydrogels can be obtained at a weight ratio of GO to reducing agent at 1:2 [28], the weight ratio of GO to glucose was set at 1:2, while the examined weight ratio of GO to CuSO4·5H2O (rG/C) ranged from 1:2 to 1:6. It was found that Cu2O/RGO hydrogels in a 3D cylindrical morphology in the
Conclusions
In summary, Cu2O/RGO composite aerogel was prepared by a facile one-pot hydrothermal method using glucose as reducing agent and cross-linker. The as-formed Cu2O/RGO composite aerogel shows superior photocatalytic performance in the degradation of MO under visible light due to its improved adsorption toward pollutants, enhanced light absorption ascribed to its lightweight as well as the promoted photo-generated charge separation by RGO. The aerogel can be easily separated from the aqueous
Acknowledgements
This work was supported by 973 Program (2014CB239303), NSFC (21273035), Specialized Research Fund for the Doctoral Program of Higher Education (20123514110002) and Independent Research Project of State Key Laboratory of Photocatalysis on Energy and Environment (No. 2014A03). Z. Li thanks the Award Program for Minjiang Scholar Professorship for financial support.
References (40)
- et al.
Enhanced photocatalytic activity and stability of Z-scheme Ag2CrO4–GO composite photocatalysts for organic pollutant degradation
Appl. Catal. B: Environ.
(2015) - et al.
Enhanced photocatalytic activity of hierarchical macro/mesoporous TiO2-graphene composites for photodegradation of acetone in air
Appl. Catal. B: Environ.
(2012) - et al.
3D BiOI–GO composite with enhanced photocatalytic performance for phenol degradation under visible-light
Ceram. Int.
(2015) - et al.
Photo-assisted synthesis of Ag3PO4/reduced graphene oxide/Ag heterostructure photocatalyst with enhanced photocatalytic activity and stability under visible light
Appl. Catal. B: Environ.
(2014) - et al.
A novel surface-enhanced Raman spectroscopy substrate based on hybrid structure of monolayer graphene and Cu nanoparticles for adenosine detection
Appl. Surf. Sci.
(2015) - et al.
A novel nanocomposite based on TiO2/Cu2O/reduced graphene oxide with enhanced solar-light-driven photocatalytic activity
Appl. Surf. Sci.
(2015) - et al.
Synthesis and photocatalytic activity of graphene based doped TiO2 nanocomposites
Appl. Surf. Sci.
(2014) - et al.
BiPO4/reduced graphene oxide composites photocatalyst with high photocatalytic activity
Appl. Surf. Sci.
(2014) - et al.
Synthesis and characterization of graphene oxide modified AgBr nanocomposites with enhanced photocatalytic activity and stability under visible light
Appl. Surf. Sci.
(2014) - et al.
TiO2/RGO composite aerogels with controllable and continuously tunable surface wettability for varied aqueous photocatalysis
Appl. Catal. B: Environ.
(2015)
Preparation and characterizations of Cu2O/reduced graphene oxide nanocomposites with high photo-catalytic performances
Powder Technol.
Nano-photocatalytic materials: possibilities and challenges
Adv. Mater.
Semiconductor-mediated photodegradation of pollutants under visible-light irradiation
Chem. Soc. Rev.
Versatile graphene-promoting photocatalytic performance of semiconductors: basic principles, synthesis, solar energy conversion, and environmental applications
Adv. Funct. Mater.
Synergetic effect of MoS2 and graphene as cocatalysts for enhanced photocatalytic H2 production activity of TiO2 nanoparticles
J. Am. Chem. Soc.
Graphene-based photocatalytic composites
RSC Adv.
Graphene-based semiconductor photocatalysts
Chem. Soc. Rev.
Advanced charge utilization from NaTaO3 photocatalysts by multilayer reduced graphene oxide
Chem. Mater.
Artificial photosynthesis over graphene-semiconductor composites. Are we getting better?
Chem. Soc. Rev.
Self-assembling TiO2 nanorods on large graphene oxide sheets at a two-phase interface and their anti-recombination in photocatalytic applications
Adv. Funct. Mater.
Cited by (96)
Enhanced interfacial charge transfer via in-situ construction of integrated NiO/NiCo<inf>2</inf>O<inf>4</inf> heterojunction coupled with carbon layer for high-performance supercapacitor and photocatalysis
2023, Colloids and Surfaces A: Physicochemical and Engineering AspectsCu-loaded reduced graphene oxide with ultrahigh adsorption performance for tetracycline from aqueous solution
2023, Journal of the Taiwan Institute of Chemical EngineersConfined and mediated intercalation of nanoparticles in graphene oxide membrane to fine-tune desalination performance
2023, Chemical Engineering Journal