{'fraction_non_alphanumeric': 0.05184659090909091, 'fraction_numerical': 0.0007102272727272727, 'mean_word_length': 4.870833333333334, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The Tribological Properties of Reduced Graphene Oxide Doped by N and B Species with Different Configurations.

The reduced graphene oxide (rGO) was doped by nitrogen (N) and/or boron (B), leading to four different configurations: N-rGO (N-doped rGO), B-rGO (B-doped rGO), N-B-rGO (N and B co-doped rGO with formation of B-N bond) and N,B-rGO (N and B isolate-doped rGO without formation of B-N bond). The preparations of different configurations were controlled by the chemical vapor deposition procedure, and their structures were further confirmed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and X-ray diffraction (XRD). The tribological performance of which was further tested via a ball-on-flat tribometer under 5 N loads. The N,B-rGO displayed a better friction-reducing and antiwear performance than N-rGO and B-rGO, while N-B-rGO presented a poorer tribological property. The morphology and component of the wear track after friction were further explored, revealing that N,B-rGO can be adsorbed on the rubbing surface to form a graphene-based protective layer, while N-B-rGO cannot. In addition, first-principles calculations based on density functional theory further confirmed a stronger interfacial energy of N,B-rGO on steel surface than that of N-B-rGO on the steel surface, which was in accordance with the experimental results.