First approach of fractals nickel-copper dendrites on stainless steelelectrodes for ammonia oxidation to nitrogen monitored in operando by differential electrochemical mass spectroscopy Felipe Matamala-Troncoso, Sergio Díaz Coello, Francisco Martínez, Herna Barrientos, Judit Lisoni, Francisco Armijo, David Lozano, Jaime Pizarro, María del