Nitrogen-doped porous carbon nanospheres derived from hyper-crosslinked polystyrene as lubricant additives for friction and wear reduction

Boron–Nitrogen Codoped Carbon Nanosheets as Oil-Based Lubricant Additives for Antioxidation, Antiwear, and Friction Reduction

“…After assisted doping of B atoms, the configuration of N atoms was altered dramatically, with the ratio of N-Q reducing markedly while the ratio of N-5 and N-6 increasing greatly. Besides, as listed in Table S1, the surface content of N approximately doubled from 5.46 to 10.44 atom %, which accounted for stronger surface polarity due to the higher electronegativity of N compared to C, thus making for better dispersion of carbon nanosheets in base oil and tighter adsorption on the surface of tribopairs . The fine spectrum of the 1s orbital of B in B,N@PCNS is displayed in Figure c.…”

“…Besides, as listed in Table S1, the surface content of N approximately doubled from 5.46 to 10.44 atom %, which accounted for stronger surface polarity due to the higher electronegativity of N compared to C, thus making for better dispersion of carbon nanosheets in base oil and tighter adsorption on the surface of tribopairs. 13 The fine spectrum of the 1s orbital of B in B,N@PCNS is displayed in Figure 2c. Combined with the N 1s fine spectra, it can be concluded that the major bonding forms of B atoms in carbon nanosheets and that they bonded with N atoms and O atoms to a certain degree.…”

“…12−20 Wang et al verified that N-doping porous carbon nanospheres performed better than those without doping in both lubrication and antiwear. 13 Li et al summarized the mechanism of S-/Pcontaining nanoadditives working under extreme pressure as the polar adsorption on the surface of steel at first, which later led to the formation of a robust tribofilm that could resist violent friction. 15 Fan et al discovered that fluorinated graphene had superior self-lubricating ability than graphene, as the introduction of F atoms destroyed the regular hexagonal structure of the carbon ring in graphene, resulting in the whittling of the π−π interaction between hexagonal rings and thus reducing the interlayer shear resistance.…”

Nitrogen-Doped Carbon Dot as a Lubricant Additive in Polar and Non-polar Oils for Superior Tribological Properties via Condensation Reaction

“…The appearance of the Fe–O peak may be the metal oxide formed in the friction process . The N 1s spectrum (Figure b) shows peaks with binding energies of about 398.6, 399.4, and 400.1 eV, which was attributed to the C–N and −NH groups in the carbonitrides after carbamide-assisted carbonization . It can be seen in Figure c that the characteristic peaks appear when the binding energies were 706.4, 709.1, 714.0, 717.0, and 720.1 eV, which confirms the existence of metal oxides Fe 2 O 3 and Fe 3 O 4 . − Similarly, the Fe–O (528.4 eV) peak also appears in the O 1s fine spectrum (Figure d) of the worn surface lubricated by 0.12 wt % NCD PAO10 dispersion, corresponding to the peaks of Fe 2 O 3 and Fe 3 O 4 in the Fe 2p fine spectrum (Figure f).…”

“…Common carbon-based nanomaterials, such as graphene, , carbon nanotubes, , fullerene, , carbon nanospheres, and carbon dots (CDs), , have shown excellent lubrication performance. In order to enhance their tribological properties, element doping (such as sulfur, phosphorus, nitrogen, and other doped elements) is often used to further improve its dispersion stability and chemical activity. , For example, Wang et al doped carbon nanospheres with nitrogen, so that the doping elements are evenly distributed in the carbon nanospheres, thereby forming a protective film composed of nitrides and metal oxides in the friction chemical reaction, which improves the lubrication performance of 500SN. Ye et al doped organic carbon nanospheres with two elements (nitrogen and phosphorus) to promote the affinity of the additive to the metal surface and form a protective film consisting of nitrides, phosphates, and metal oxides on the surface.…”