Graphitization with Suppressed Carbon Loss for High-Quality Reduced Graphene Oxide

Abstract

An efficient reduction method to obtain high-quality graphene sheets from mass-producible graphene oxide is highly desirable for practical applications. Here, we report an in situ deoxidation and graphitization mechanism for graphene oxide that allows for high-quality reduced graphene oxide sheets under the low temperature condition (<300 °C) by utilizing a well-known Fischer–Tropsch reaction catalyst (CuFeO2). By applying modified FTR conditions, where graphene oxide was reduced on the catalyst surface under the hydrogen-poor condition, deoxidation with much suppressed carbon loss was possible, resulting in high-quality graphene sheets. Our experimental data and density functional theory calculations proved that reduction which occurred on the CuFeO2 surface preferentially removed adsorbed oxygen atoms in graphene oxide sheets, leaving dissociated carbon structures to be restored to a near-perfect few-layer graphene sheet. TGA-mass data revealed that GO with catalysts released 92.8% less carbon-containing gases than GO without catalysts during the reduction process, which suggests that this process suppressed carbon loss in graphene oxide sheets, leading to near-perfect graphene. The amount of oxygen related to the epoxide group in the basal plane of GO significantly decreased to near zero (from 43.84 to 0.48 at. %) in catalyst-assisted reduced graphene oxide (CA-rGO). The average domain size and the density of defects of CA-rGO were 4 times larger and 0.1 times lower than those for thermally reduced graphene oxide (TrGO), respectively. As a result, CA-rGO had a 246 and 8 times lower electrical resistance than TrGO and CVD-graphene. With these performances, CA-rGO coated paper connected to a coin-cell battery successfully lit an LED bulb, and CA-rGO itself acted as an efficient catalyst for both the hydrogen evolution reaction and the oxygen evolution reaction.

Highly Stable Iron‐ and Carbon‐Based Electrodes for Li‐Ion Batteries: Negative Fading and Fast Charging within 12 Min

“…The reduction of rGO induced by the corresponding oxidation of Fe in the Fe 3 O 4 @rGO‐65 composite, with high binding energy of an oxygen atom, was further verified by XPS analysis (Figure 3b–e) [42] . In the high‐resolution C1s XPS spectra of pristine rGO and Fe 3 O 4 @rGO‐65 (Figure 3b), the shift of the deconvoluted peaks to lower binding energies in COOH, C−O, and C=O of Fe 3 O 4 @rGO suggests deoxygenation of rGO [40,43,44] .…”

“…The reduction of rGO induced by the corresponding oxidation of Fe in the Fe 3 O 4 @rGO-65 composite, with high binding energy of an oxygen atom, was further verified by XPS analysis (Figure 3b-e). [42] In the high-resolution C1s XPS spectra of pristine rGO and Fe 3 O 4 @rGO-65 (Figure 3b), the shift of the deconvoluted peaks to lower binding energies in COOH, CÀ O, and C=O of Fe 3 O 4 @rGO suggests deoxygenation of rGO. [40,43,44] Meanwhile, in the high-resolution Fe2p XPS spectrum (Fig- ure 3c-e and Figure S6), the Fe2p 3/2 (711.28 eV) and Fe2p 1/2 (724.94 eV) peaks of Fe 3 O 4 @rGO-65, corresponding to the magnetite phase, appeared at higher binding energies compared to Fe 3 O 4 prepared without rGO, demonstrating additional oxidation of Fe 3 O 4 on the rGO sheets.…”

Carbon Graphitization: Towards Greener Alternatives to Develop Nanomaterials for Targeted Drug Delivery

“…In a similar way, rGO for Ni(II) removal was obtained using Tecoma stans leaf extract to reduce GO [ 135 ]. Finally, in a recent work, a catalytic reduction process to obtain a very high-quality rGO was reported [ 134 ]. In this case, the use of a Fischer–Tropsch catalyst in the absence of hydrogen allowed it to operate at the very low temperature of 250 °C, with oxygen as the only byproduct.…”

High‐Quality Monolayer Reduced Graphene Oxide Films via Combined Chemical Reduction and Ethanol‐Assisted Defect Restoration

“…have reported in situ deoxygenation and graphitization of GO using Fischer–Tropsch reaction catalyst (CuFeO 2 ) to obtain high‐quality few‐layered (5–10 layers) RGO with an I D / I G ratio of 0.19 and a crystallite size of 95.57 nm. [ 21 ] Yet, the total process time can be longer, as 12 h, involving several steps. Voiry et al.…”

“…Recently, Yoon et al have reported in situ deoxygenation and graphitization of GO using Fischer-Tropsch reaction catalyst (CuFeO 2 ) to obtain high-quality few-layered (5-10 layers) RGO with an I D /I G ratio of 0.19 and a crystallite size of 95.57 nm. [21] Yet, the total process time can be longer, as 12 h, involving several steps. Voiry et al has reported a microwave-assisted reduction of GO into high-quality RGO with a lower I D /I G ratio, a large crystallite size (180 nm), and a large distance between defects (38 nm).…”