**Acknowledgments**

The authors acknowledge Vincent Salles for spray-pyrolysis and Arnaud Brioude for the TEM observation of nanoparticles and samples annealed in the temperature range of 1450–2000 °C before ball-milling.

### **Author Contributions**

The findings in this manuscript are part of Georges Moussa thesis work. Chrystelle Salameh performed borazine synthesis. Philippe Miele, Umit B. Demirci and Samuel Bernard advised the thesis and directed the research. Alina Bruma and Sylvie Malo guided the TEM experiments of the sample B1.0N0.9-NP2000BM. The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.
