Igh temperature (273 K) was utilized to probe the microporosity of HPCs. The adsorbed quantity

Igh temperature (273 K) was utilized to probe the microporosity of HPCs. The adsorbed quantity (inset in Figure 2a) for HPC8 have close pore-structure parameters for HPCs (Table 2) recommend that even though HPCs BET particular HPC6 areas, the entire relative pressure area, indicating a can also be higher than that ofsurface inside the micropore surface area determined by the CO2 probe for HPC8 is much larger HPC8. far more developed microporosity forthan that of HPC6.Figure 2. Nitrogen sorption isotherms (a), isotherms (a), carbon dioxide sorption isotherms (inset corresponding pore size Figure 2. Nitrogen sorption carbon dioxide sorption isotherms (inset inside a) and their inside a) and their MRTX-1719 Formula distributions corresponding pore size distributions (b) for HPC6 and HPC8. (b) for HPC6 and HPC8. Table two. Surface region and pore-structure parameters for HPCs. Sample HPC6 HPC8 CaVtaSBET 843 892bSQSDFT 828 904cSmic 480 518cSmesocSNLDFT 691 787 -dS0.six nm 437 492 -dS0.six.five nm 254 295 -d(cm3 g-1 ) three.18 4.05 2.(m2 g-1 ) 348 386total pore volume measured at P/P0 = 0.995, b BET precise surface region, c total surface location (SQSDFT ), surface area for micropore (Smic ) and mesopore (Smeso ) derived from N2 QSDFT calculation, d micropore surface area (SNLDFT ), surface location for pore size 0.six nm (S0.6 nm ) and 0.six.five nm (S0.6.five nm ) derived from CO2 NLDFT calculation.The XRD patterns of HPCs (Figure 3a) exhibit a distinct peak centered at 2 = 21.two , suggesting a reasonably very good graphitization degree for HPCs. Such a outcome can coincide well with the HR-TEM observation (Figure 1e,g). The calculated d002 for HPCs is about 0.418 nm. The greater d002 worth compared with that of graphite is most likely because of the heteroatom doping, which expands the interlayer distance among adjacent carbon layers. Two distinct peaks within the Raman spectra for HPCs (Figure 3b) at 1351 and 1589 cm-1 are assigned towards the D and G bands for carbon supplies, respectively. The D band is assigned for the disorder-induced mode associated with structural defects and imperfections while the G band is assigned for the first-order scattering in the E2g mode from the sp2 carbon domains [26]. The intensity ratio IG /ID is made use of as a measure in the graphitization degree for carbon samples. Each HPCs possess an IG /ID worth larger than 1, 1.11 for HPC6 and 1.09 for HPC8, indicating an excellent graphitization degree for HPCs. The XPS analyses show that phosphorus and nitrogen are doped in HPCs (Figure 3c). The N 1s spectrum may be deconvolved into three peaks at 398.1, 400.5 and 403.three eV, which may very well be assigned to pyridinic (N1), pyrrolic (N2) and pyridine-N-oxide (N3) nitrogen species, Fmoc-Gly-Gly-OH supplier respectively [27]. The P 2p spectrum could be deconvolved into 3 peaks at 131.two, 132.eight and 134.3 eV, corresponding to P-C bonding (P1), pyrophosphate ([P2 O7 ]4- , P2) and metaphosphate ([PO3 ]- , P3) species, respectively [22]. The contents of N and P (Table 1) in HPCs suggests that nitrogen would escape below a high-temperature remedy although P prefers to remain below a higher temperature.Nanomaterials 2021, 11, 2838 Nanomaterials 2021, 11, x FOR PEER REVIEW7 7 of12 ofFigure three. (a) XRD patterns, (b) Raman spectra, (c) XPS convey, N 1s and P 2p spectra for HPCs. Figure three. (a) XRD patterns, (b) Raman spectra, (c) XPS convey, N 1s and P 2p spectra for HPCs.Electrochemical measurements had been systematically employed in 1 M H2SO4 and six M two SO4 and six M Electrochemical measurements were KOH electrolytes in aa three-electrode method. is shown that that.