Synthesis of cobalt-impregnated carbon composite derived from a renewable resource: Characterization and catalytic performance evaluation
Graphical abstract
Introduction
Catalysts have been frequently utilized in various fields of chemistry, physics and biology due to their high reactivity and efficiency. However, there can be a considerable loss of catalytic activity resulting from particle aggregation and instability due to inherent high surface energy, especially in the homogenous catalyst system (Wang et al., 2017). To resolve this issue, efforts have been made to develop heterogeneous catalysts with improved recyclability and sustainability (Bennett et al., 2016, Joshi et al., 2016, Roschat et al., 2016). The use of heterogeneous catalysts to promote desired reactions for various applications such as organic synthesis, conversion to value-added products, and degradation of pollutants has received considerable attention (Hajduk et al., 2017, Liu et al., 2017; J. Liu et al., 2017, Taifan and Baltrusaitis, 2016, Wang et al., 2014).
Many studies have been reported on the catalytic conversion of target chemicals using catalysts containing noble metals (Pt, Au, Ag, Rh, Ru, Pd, etc.) (Fang et al., 2017, Louie et al., 2017, Song et al., 2017). However, despite their high performances, noble metals-based catalysts are seldom used in scaled-up applications because of high cost and limited availability of the noble metals.
In recent, the potential utility of cobalt (Co) in triggering catalytic reactions has been examined as an alternative to the noble metals due to its low cost. For example, Hasan et al. (2016) fabricated a magnetic Co‑carbon composite via calcination of cobalt-based metal organic frameworks (MOFs) and demonstrated its catalytic capability in converting p-nitrophenol (PNP) into p-aminophenol (PAP), which is a useful chemical for pharmaceuticals, dyestuffs, and agrochemicals (Guo et al., 2016). In addition, Co-loaded polymers with hierarchical porous structures were prepared as a stable catalyst for PNP conversion into PAP (Zhao et al., 2016).
Carbon-based materials have gained much attention for use as support materials for catalytic metals to provide structural integrity and other desirable properties. For instance, activated carbon supports with high surface area and hierarchical porous structure have shown excellent conversion and selectivity in catalytic applications (Mouat et al., 2016, Si et al., 2017). Carbon materials prepared with renewable resources have been recently employed in the preparation of catalytic materials (Lee et al., 2017, Liu et al., 2016, Yao et al., 2016). Our previous work has used lignin as a carbon precursor to synthesize Co-biochar catalyst composite and validated its great catalytic performance in conversion of bromate (Cho et al., 2017). Xu et al. (2015) proposed environmentally benign method to prepare 3D porous graphene by converting waste papers mixed with a cobalt(II) complex. With such efforts, utilizing biomass- or biowaste-derived carbonaceous materials (i.e., biochar) is evolving into a viable option in production of environmental catalysts. In addition, a good number of recent studies have explored the potential of biochar for the use in various catalytic/environmental applications (Dehkhoda and Ellis, 2013, Kastner et al., 2015, Mohan et al., 2014, Ren et al., 2014).
Glucose derived from the hydrolysis of cellulose is a common carbon source which has merits of low cost, easy access, and fast regeneration (Tian et al., 2016). Thus, glucose was chosen as a carbon support precursor for the synthesis of biochar-based Co catalyst. Recently, nitrogen (N) doping onto the catalysts has showed enhanced catalytic performances as compared to the catalysts without N-doping (Wang et al., 2015). Blending N-containing ligands with carbon precursor followed by pyrolysis is a facile method to provide N dopant to the catalyst, and therefore melamine that contains high amount of nitrogen was used as N donor in this work. The biochar was characterized by spectroscopic and surface analyses. The catalytic ability of the biochar was compared with that of the biochar without N doping. A series of PNP conversion experiments were performed under varying experimental parameters such as NaBH4 concentration, composite dosage, and initial PNP concentration. The reusability of the biochar was also examined to demonstrate the longevity of catalytic ability of the biochar.
Section snippets
Chemical reagents & materials
Cobalt chloride hexahydrate (CoCl2 ∙ 6H2O, 99%), D-(+)-Glucose (C6H12O6) and melamine (C3H6N6, 99%) were obtained from Sigma Aldrich, USA. p-Nitrophenol (PNP, C6H5NO3, 99%) and sodium borohydride (NaBH4) were purchased from Alfa Aesar, USA and Daejung Chemical, Korea, respectively. Solutions were prepared with ultrapure deionized distilled water (DDW, 18.2 MΩ cm− 1).
Synthesis of biochar catalyst
The mixture solution of Co/glucose/melamine was prepared by adding 1 g CoCl2 ∙ 6H2O, 4 g glucose and 1 g melamine into 20 mL DDW. An alumina
Physicochemical properties of Co-NB
To explore the morphology and particle distribution of Co-NB, FE-SEM and TEM imaging along with elemental mapping by EDS were used. The results presented in Fig. 1 reveal that Co-NB possessed irregular layers of thin carbon support on which nanoparticles in the size range of 20–60 nm were evenly deposited (Fig. 1a, b). The elemental mapping of Co-NB in the EDS analysis exhibited 94.57 wt% C, 1.56 wt% O, and 3.87 wt% Co (Fig. 1c, d, e), suggesting carbonization (i.e., graphitization) thermally
Conclusions
In this study, N-doped Co biochar was prepared by pyrolysis of mixture of glucose, Co(II), and melamine in a single process. The Co nanoparticles (20–60 nm) evenly dispersed on the carbon surface of the biochar were found in TEM/EDS mapping. The analyses of XRD, XPS, Raman and BET revealed the metallic Co phases (CoO and Co0), N-doped graphitic carbon layers (pyridinic N and pyrrolic N), and highly hierarchical porous structure. Compared to the Co biochar without N-doping, the enhancement of PNP
Acknowledgement
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1A09000800).
References (48)
- et al.
Reduced graphene oxide decorated with Co3O4 nanoparticles (rGO-Co3O4) nanocomposite: a reusable catalyst for highly efficient reduction of 4-nitrophenol, and Cr(VI) and dye removal from aqueous solutions
Chem. Eng. J.
(2017) - et al.
Oxygen vacancy enhanced catalytic activity of reduced Co3O4 towards p-nitrophenol reduction
Appl. Catal. B Environ.
(2017) - et al.
One-pot green synthesis of silver/iron oxide composite nanoparticles for 4-nitrophenol reduction
J. Hazard. Mater.
(2013) - et al.
Biochar-based catalyst for simultaneous reactions of esterification and transesterification
Catal. Today
(2013) - et al.
Synthesis of Pd/Au bimetallic nanoparticle-loaded ultrathin graphitic carbon nitride nanosheets for highly efficient catalytic reduction of p-nitrophenol
J. Colloid Interface Sci.
(2017) - et al.
Co-based heterogeneous catalysts from well-defined α-diimine complexes: discussing the role of nitrogen
J. Catal.
(2017) - et al.
Reduction of nitrophenols to aminophenols under concerted catalysisby Au/g-C3N4 contact system
Appl. Catal. B Environ.
(2017) - et al.
One-step synthesis of hollow porous gold nanoparticles with tunable particle size for the reduction of 4-nitrophenol
J. Hazard. Mater.
(2016) - et al.
COx-free hydrogen production via decomposition of ammonia over Cu–Zn-based heterogeneous catalysts and their activity/stability
Appl. Catal. B Environ.
(2017) - et al.
Reduction of p-nitrophenol by magnetic Co-carbon composites derived from metal organic frameworks
Chem. Eng. J.
(2016)
N doped cobalt-carbon composite for reduction of p-nitrophenol and pendimethaline
J. Alloys Compd.
Microwave enhanced alcoholysis of non-edible (algal, jatropha and pongamia) oils using chemically activated egg shell derived CaO as heterogeneous catalyst
Bioresour. Technol.
Catalytic decomposition of tar using iron supported biochar
Fuel Process. Technol.
Evaluating the effectiveness of various biochars as porous media for biodiesel synthesis via pseudo-catalytic transesterification
Bioresour. Technol.
Direct aerobic oxidative homocoupling of benzene to biphenyl over functional porous organic polymer supported atomically dispersed palladium catalyst
Appl. Catal. B Environ.
Metallic cobalt nanoparticles imbedded into ordered mesoporous carbon: a non-precious metal catalyst with excellent hydrogenation performance
J. Colloid Interface Sci.
Kinetics of hydrogenation and hydrogenolysis of 2,5-dimethylfuran over noble metals catalysts under mild conditions
Appl. Catal. B Environ.
Highly active layered double hydroxide-derived cobalt nano-catalysts for p-nitrophenol reduction
Appl. Catal. B Environ.
Fe-g-C3N4/graphitized mesoporous carbon composite as an effective Fenton-like catalyst in a wide pH range
Appl. Catal. B Environ.
Organic and inorganic contaminants removal from water with biochar, a renewable, low cost and sustainable adsorbent - a critical review
Bioresour. Technol.
Economical and green biodiesel production process using river snail shells-derived heterogeneous catalyst and co-solvent method
Bioresour. Technol.
Synthesis of graphene encapsulated Fe3C in carbon nanotubes from biomass and its catalysis application
Carbon
CH4 conversion to value added products: potential, limitations and extensions of a single step heterogeneous catalysis
Appl. Catal. B Environ.
Magnetic ordered mesoporous copper ferrite as a heterogeneous Fenton catalyst for the degradation of imidacloprid
Appl. Catal. B Environ.
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2022, Journal of Alloys and CompoundsCitation Excerpt :However, the high cost and scarcity of noble metal greatly limit their application. Transition metals and their oxides are alternative catalysts due to their high abundance and low cost [20], especially Co [20,21], Ni [22], Fe [23] or alloy [24] based metal or oxide catalysts. For instance, transition metal/N-doped carbon nanocatalysts are often applied as catalysts in various chemical reactions where the N-doped carbon (NC) is often prepared by pyrolysis of mixtures including melamine [20] or metal-organic-frameworks [25] containing a nitrogen ligand.
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These authors equally contributed.