Boron/phosphorus doping for retarding the oxidation of reduced graphene oxide
Introduction
Since the isolation of graphene monolayer in 2004, graphene has attracted great attention for preparing advanced functional materials with diverse applications. Due to its unprecedented electrical, mechanical and thermal properties, graphene has been explored in various applications, such as electronic devices, sensors, catalysts and polymer composites [1]. The preparation route from graphene oxide (GO) is regarded as one of the most suitable methods to prepare graphene in large quantities [2]. During the reduction of GO by chemical or thermal treatment, most of the labile oxygen functionalities are removed from the surface of GO. Thus, reduced graphene oxide (RGO) is more thermally stable than GO. However, the RGO prepared shows poor thermal stability under oxidizing conditions and its oxidation stage with marked weigh loss is observed at even as low as 400 °C [3], [4]. The disadvantage of poor oxidation resistance limits the application of graphene at elevated temperatures, such as friction components, coatings, fuel cells and flame retardant composites [5], [6]. It is well known that the oxidation of graphitic materials initiates from the vulnerable areas, such as defects, dislocations, vacancies and functional groups [7].
Recent studies have demonstrated that doping of foreign heteroatoms is one of the most effective strategies for tailoring the electrochemical properties of graphene [1], [5], [8]. The article published by Sandoval et al. proved that the presence of N atoms within RGO nanosheets induces a remarkable increase in the thermal oxidative stability [5]. Sandoval et al. analyzed the enhancement mechanism by estimating the combustion enthalpy of pyrrolic, pyridinic, graphitic N and graphene [5]. Pyrrolic, pyridinic and graphitic N are expected to possess higher stability against combustion than graphene [8]. The phenomena of enhanced oxidation resistance of RGO by doping of other heteroatoms have been presented in some previous reports [4], [8], [9], [10]. However, to the best of our knowledge, the thermal oxidative stability and related enhancement mechanism for the doped RGO have not yet been systematically investigated.
To gain insights into the effect of the doped heteroatoms on the thermal oxidation of RGO, B/P atoms were introduced into RGO by a simple high temperature annealing approach. The thermal oxidative stability of B/P and N co-doped RGO was compared with that of single N-doped RGO. The mechanism for enhanced thermal stability of B/P-doped RGO was proposed according to the chemical composition and bonding configuration analysis.
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Materials
Graphite powder (granularity ≤ 30 μm, chemically pure), ammonium hydroxide (25–28%, analytical reagent (AR)), hydrazine hydrate (85%, AR), concentrated phosphoric acid (85%, AR), boric acid (AR) and hydrochloric acid (37%, AR) were purchased from Sinopharm Chemical Reagent Co., Ltd. The water used was deionized water produced in our laboratory.
Preparation of B/P-doped RGO
Graphite oxide and RGO were prepared according to the methods described in our previous studies [11], [12]. Briefly, graphite oxide was prepared from
Results and discussion
FTIR spectra of the samples are shown in Fig. 1a. The peaks at around 1570 cm−1 in these spectra are attributed to the skeletal vibration of graphene [13]. The residual oxygen functional groups in RGO appear as a broad band at 1165 cm−1 [14]. The peak at 1182 cm−1 in the spectrum of B-RGO corresponds to the B–O deformation vibration [15]. The absorption of C–O and B–C may be integrated into the peak at 1106 cm−1 [16]. A marked peak at 803 cm−1 may be assigned to B–N bending in B-RGO [15]. A
Conclusions
B or P and N dual-doped graphene was successfully synthesized using thermal annealing method. The mixture of boric/phosphoric acid and RGO prepared by hydrazine reduction was directly pyrolyzed in a tubular furnace. The results of FTIR and XPS clearly confirmed that B and P atoms were incorporated into the lattice of graphene. The doped RGOs, especially P-RGO, exhibited exceptional thermal oxidative stability. The doped heteroatoms on the RGO nanosheets reduced the reactivity of carbon active
Acknowledgements
Support for this work is provided by the National Natural Science Foundation of China (Grant No. 21374111, 51403196 and 51203146), the Natural Science Foundation of Jiangsu Province (Grant No. BK20130369), the Research Grants Council of the Hong Kong Special Administrative Region, China (Grant No. 9042221, CityU 11300215) and the Fundamental Research Funds for the Central Universities (Grant No. WK2320000032).
References (35)
- et al.
The reduction of graphene oxide
Carbon
(2012) - et al.
Ultrasonication-assisted ultrafast reduction of graphene oxide by zinc powder at room temperature
Carbon
(2011) - et al.
Preparation of carbon foams with enhanced oxidation resistance by foaming molten sucrose using a boric acid blowing agent
Carbon
(2013) - et al.
Design of artificial nacre-like hybrid films as shielding to mitigate electromagnetic pollution
Carbon
(2014) - et al.
Facile synthesis of boron and nitrogen-doped graphene as efficient electrocatalyst for the oxygen reduction reaction in alkaline media
Int. J. Hydrog. Energ
(2014) - et al.
Preparation of functionalized graphene oxide/polypropylene nanocomposite with significantly improved thermal stability and studies on the crystallization behavior and mechanical properties
Chem. Eng. J.
(2014) - et al.
Forming mechanism of nitrogen doped graphene prepared by thermal solid-state reaction of graphite oxide and urea
Appl. Surf. Sci.
(2011) - et al.
Pyrolytic synthesis of boron-doped graphene and its application as electrode material for supercapacitors
Electrochim Acta
(2013) - et al.
On the chemical structure of phosphorus compounds in phosphoric acid-activated carbon
Appl. Surf. Sci.
(2006) - et al.
Enhanced electrocatalytic activity due to additional phosphorous doping in nitrogen and sulfur-doped graphene: A comprehensive study
Carbon
(2014)
Characterisation of boron-doped coal-derived carbon foams and their oxidation behaviour
Fuel
The role of substitutional boron in carbon oxidation
Carbon
Inhibition of catalytic oxidation of carbon/carbon composites by boron-doping
Carbon
Influence of hybrid functionalized graphite nanoplatelets-tripolyphosphate on improvement in fire protection of intumescent fire resistive coating for steel structures
Polym. Degrad. Stabil.
Graphene-based macroscopic assemblies and architectures: an emerging material system
Chem. Soc. Rev.
Doped Graphene Sheets As Anode Materials with Superhigh Rate and Large Capacity for Lithium Ion Batteries
ACS Nano
Enhanced thermal oxidation stability of reduced graphene oxide by nitrogen doping
Chem. Eur. J.
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These authors contributed equally to this work.