Efficient Synthesis of Heteroatom (N or S)‐Doped Graphene Based on Ultrathin Graphene Oxide‐Porous Silica Sheets for Oxygen Reduction Reactions

Abstract

Heteroatom (N or S)-doped graphene with high surface area is successfully synthesized via thermal reaction between graphene oxide and guest gases (NH 3 or H 2 S) on the basis of ultrathin graphene oxide-porous silica sheets at high temperatures. It is found that both N and S-doping can occur at annealing temperatures from 500 to 1000 ° C to form the different binding confi gurations at the edges or on the planes of the graphene, such as pyridinic-N, pyrrolic-N, and graphitic-N for N-doped graphene, thiophenelike S, and oxidized S for S-doped graphene. Moreover, the resulting N and S-doped graphene sheets exhibit good electrocatalytic activity, long durability, and high selectivity when they are employed as metal-free catalysts for oxygen reduction reactions. This approach may provide an effi cient platform for the synthesis of a series of heteroatom-doped graphenes for different applications.

Development and Simulation of Sulfur‐doped Graphene Supported Platinum with Exemplary Stability and Activity Towards Oxygen Reduction

“…These peaks can be attributed to sulfur bonded directly to the carbon atoms in a heterocyclic configuration as no elemental sulfur was observed by XRD or TEM, and (if present) would have been removed by the rigorous washing procedure employed after SG synthesis. We also speculate that these C‐S‐C species exist in the thiophene form, a notion consistent with previously reported investigations and supported by our formation energy calculations discussed later on. Furthermore, thiophene species exist in a pentagonal arrangement, thereby residing on the edge plane and defect sites of SG and most likely giving rise to the strong emergence of the D‐band observed through Raman spectroscopy.…”

Development and Simulation of Sulfur‐doped Graphene Supported Platinum with Exemplary Stability and Activity Towards Oxygen Reduction

“…These peaks can be attributed to sulfur bonded directly to the carbon atoms in a heterocyclic configuration as no elemental sulfur was observed by XRD or TEM, and (if present) would have been removed by the rigorous washing procedure employed after SG synthesis. We also speculate that these C‐S‐C species exist in the thiophene form, a notion consistent with previously reported investigations and supported by our formation energy calculations discussed later on. Furthermore, thiophene species exist in a pentagonal arrangement, thereby residing on the edge plane and defect sites of SG and most likely giving rise to the strong emergence of the D‐band observed through Raman spectroscopy.…”

Evidence of covalent synergy in silicon–sulfur–graphene yielding highly efficient and long-life lithium-ion batteries

“…The S 2p doublet corresponding to the sulfide (C–S–C) structure is observed at 164.0 and 165.2 eV and labelled as (1) and (2). These peak locations are in good agreement with the reported S 2p3/2 and S 2p1/2 spin orbit couplet 34 35 36 . The other minor peaks labelled as (3) in Fig.…”

Template‐Free Self‐Caging Nanochemistry for Large‐Scale Synthesis of Sulfonated‐Graphene@Sulfur Nanocage for Long‐Life Lithium‐Sulfur Batteries

“…The S 2p XPS spectra of the SG@S nanocage can be resolved into three different peaks at the binding energies of ≈163.9, 165.1, and 168.4 eV, respectively (Figure 2c). The former two peaks are in agreement with the reported S 2p 3/2 and S 2p 1/2 positions of CSC bonds, [38][39][40][41] while the peak at 168.4 eV is related to the oxidized sulfur (CSO 2 C). [38][39][40][41] All the peaks indicate that the S atoms Figure 1.…”

“…The former two peaks are in agreement with the reported S 2p 3/2 and S 2p 1/2 positions of CSC bonds, [38][39][40][41] while the peak at 168.4 eV is related to the oxidized sulfur (CSO 2 C). [38][39][40][41] All the peaks indicate that the S atoms Figure 1. Template-free self-caging nanochemistry for the synthesis of advanced sulfonated-graphene@sulfur (SG@S) nanocage particles with ondemand functions: Accommodation of volume change, good electronic conductivity, and superior physical and chemical trapping of polysulfides.…”

Development and Simulation of Sulfur‐doped Graphene Supported Platinum with Exemplary Stability and Activity Towards Oxygen Reduction

“…These peaks can be attributed to sulfur bonded directly to the carbon atoms in a heterocyclic configuration as no elemental sulfur was observed by XRD or TEM, and (if present) would have been removed by the rigorous washing procedure employed after SG synthesis. We also speculate that these C‐S‐C species exist in the thiophene form, a notion consistent with previously reported investigations and supported by our formation energy calculations discussed later on. Furthermore, thiophene species exist in a pentagonal arrangement, thereby residing on the edge plane and defect sites of SG and most likely giving rise to the strong emergence of the D‐band observed through Raman spectroscopy.…”

Evidence of covalent synergy in silicon–sulfur–graphene yielding highly efficient and long-life lithium-ion batteries

“…The S 2p doublet corresponding to the sulfide (C–S–C) structure is observed at 164.0 and 165.2 eV and labelled as (1) and (2). These peak locations are in good agreement with the reported S 2p3/2 and S 2p1/2 spin orbit couplet 34 35 36 . The other minor peaks labelled as (3) in Fig.…”

Template‐Free Self‐Caging Nanochemistry for Large‐Scale Synthesis of Sulfonated‐Graphene@Sulfur Nanocage for Long‐Life Lithium‐Sulfur Batteries

“…The S 2p XPS spectra of the SG@S nanocage can be resolved into three different peaks at the binding energies of ≈163.9, 165.1, and 168.4 eV, respectively (Figure 2c). The former two peaks are in agreement with the reported S 2p 3/2 and S 2p 1/2 positions of CSC bonds, [38][39][40][41] while the peak at 168.4 eV is related to the oxidized sulfur (CSO 2 C). [38][39][40][41] All the peaks indicate that the S atoms Figure 1.…”

“…The former two peaks are in agreement with the reported S 2p 3/2 and S 2p 1/2 positions of CSC bonds, [38][39][40][41] while the peak at 168.4 eV is related to the oxidized sulfur (CSO 2 C). [38][39][40][41] All the peaks indicate that the S atoms Figure 1. Template-free self-caging nanochemistry for the synthesis of advanced sulfonated-graphene@sulfur (SG@S) nanocage particles with ondemand functions: Accommodation of volume change, good electronic conductivity, and superior physical and chemical trapping of polysulfides.…”

Development and Simulation of Sulfur‐doped Graphene Supported Platinum with Exemplary Stability and Activity Towards Oxygen Reduction

“…These peaks can be attributed to sulfur bonded directly to the carbon atoms in a heterocyclic configuration as no elemental sulfur was observed by XRD or TEM, and (if present) would have been removed by the rigorous washing procedure employed after SG synthesis. We also speculate that these C‐S‐C species exist in the thiophene form, a notion consistent with previously reported investigations and supported by our formation energy calculations discussed later on. Furthermore, thiophene species exist in a pentagonal arrangement, thereby residing on the edge plane and defect sites of SG and most likely giving rise to the strong emergence of the D‐band observed through Raman spectroscopy.…”

Evidence of covalent synergy in silicon–sulfur–graphene yielding highly efficient and long-life lithium-ion batteries

“…The S 2p doublet corresponding to the sulfide (C–S–C) structure is observed at 164.0 and 165.2 eV and labelled as (1) and (2). These peak locations are in good agreement with the reported S 2p3/2 and S 2p1/2 spin orbit couplet 34 35 36 . The other minor peaks labelled as (3) in Fig.…”

Template‐Free Self‐Caging Nanochemistry for Large‐Scale Synthesis of Sulfonated‐Graphene@Sulfur Nanocage for Long‐Life Lithium‐Sulfur Batteries

“…The S 2p XPS spectra of the SG@S nanocage can be resolved into three different peaks at the binding energies of ≈163.9, 165.1, and 168.4 eV, respectively (Figure 2c). The former two peaks are in agreement with the reported S 2p 3/2 and S 2p 1/2 positions of CSC bonds, [38][39][40][41] while the peak at 168.4 eV is related to the oxidized sulfur (CSO 2 C). [38][39][40][41] All the peaks indicate that the S atoms Figure 1.…”

“…The former two peaks are in agreement with the reported S 2p 3/2 and S 2p 1/2 positions of CSC bonds, [38][39][40][41] while the peak at 168.4 eV is related to the oxidized sulfur (CSO 2 C). [38][39][40][41] All the peaks indicate that the S atoms Figure 1. Template-free self-caging nanochemistry for the synthesis of advanced sulfonated-graphene@sulfur (SG@S) nanocage particles with ondemand functions: Accommodation of volume change, good electronic conductivity, and superior physical and chemical trapping of polysulfides.…”