Based on the revealed interactions (dissociation energy) between several typical metals (transition and rare-earth elements) and carbon atoms through the DFT quantum mechanics method, Pr can be predicted to possibly be a new potential catalyst. Indeed, Praseodymium oxide (Pr 6 O 11 ) was insightfully found to catalyze the graphitization more efficiently than the other selected additives. The effects of Pr 6 O 11 catalyst on the microstructure of the graphite anode were investigated by XRD, Raman spectroscopy, SEM, and TEM. The results indicate that Pr 6 O 11 addition remarkably improves the formation of crystallites, thereby largely enhancing the electrical property of graphite anode. The graphite anode with a low electrical resistivity of 5.0 μΩ·m was successfully available by adding 3 wt. % Pr 6 O 11 at 2800 °C. Finally, the catalytic graphitization mechanism of rare-earth element was proposed based on the experimental results.

Cubic gauche polynitrogen (cgPN) has been very attractive because of its high energy density that is 3.5 times of the TNT energy. cgPN has been investigated theoretically in detail, but few experimental studies have been reported. In 2004, cgPN was first synthesized from nitrogen gas under extremely high temperature and high pressure conditions and the trace amount of cgPN in the high-pressure vessel decomposed once the pressure was released. Until recently, our group for the first time synthesized cgPN from an NaN 3 precursor under ambient conditions with radio-frequency plasma. Here, synthesis and stabilization of cgPN are systematically investigated both computationally and experimentally. The effects of several major factors are studied, and the possible key intermediate is explored. In addition to NaN 3 , a ZEZ N 8 precursor is also used. ZEZ N 8 was synthesized by the cyclic voltammetry method. EZE N 8 is found to be the potential intermediate for cgPN formation based on the Fourier transform infrared and Raman spectra and the fact that a higher yield of cgPN is obtained with the ZEZ N 8 precursor. Na + is shown to stabilize cgPN under ambient conditions; however, an excess of Na + has a negative effect on cgPN growth. The oxygen reduction reaction (ORR) was carried out using cgPN as the cathodic catalyst, and the result shows that it is very active for the ORR, which is comparable with a commercial Pt/carbon catalyst. Moreover, cgPN shows an excellent stability during the ORR. This work guides the rational synthesis and scaleup of cgPN and its practical applications for the ORR.

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Polynitrogen (PN) deposited on multiwalled carbon nanotubes was synthesized by cyclic voltammetry with ultraviolet (UV) irradiation. Compared to the sample formed without UV, a larger amount of N8 – was synthesized and was found to distribute more uniformly on the MWNTs with 254 nm UV irradiation, indicating that the production of more azide (N3)0 radicals as the precursors for synthesis of N8 – by photoexcitation of azide (N3 –) ions is a rate-limiting step for PN synthesis. An oxygen reduction reaction kinetics study indicated a four-electron reaction pathway on N8 –, whereas a two-electron process occurs on N3 –. Analysis by in situ shell-isolated nanoparticle-enhanced Raman spectroscopy revealed that the side-on and end-on O2 adsorption occurred at N8 – and N3 –, respectively, confirming the electron transfer process. A full direct-methanol fuel cell study shows that methanol crossover typically reduces the current density of Pt/C by ∼40% but has very little effect on the performance of the PN-MWNT catalyst after testing for 120 h. Moreover, the power density from the PN-MWNT cathode is at least twice that from a Pt/C cathode.