1 Supporting Information N-doped Carbon Nanotubes enriched with graphitic Nitrogen in a Buckypaper configuration as efficient 3D electrodes for Oxygen Reduction to H 2 O 2 Enrique Contreras 1,2 , David Dominguez 2 , Hugo Tiznado 2 , Jonathan Guerrero-Sanchez 2 , Noboru Takeuchi 2 , Gabriel Alonso 2 , Oscar E. Contreras 2 , Mercedes T. Oropeza-Guzman 3 and Jose M. Romo-Herrera 2 . 1 Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Posgrado en Ciencias en Nanociencias, Carretera Ensenada-Tijuana No. 3918, Zona Playitas, CP 22860, Ensenada, BC México. 2 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México (CNyN-UNAM), Km 107 Carretera Tijuana-Ensenada, CP 22800 Ensenada, B.C., México. 3 Centro de Graduados e Investigación en Química, Instituto Tecnológico de Tijuana, Blvd. Alberto Limón Padilla s/n, Mesa de Otay, CP 22500 Tijuana, B.C., México. Figure S1 shows: a) C-C (sp2) peaks of the CNx samples at 284.6eV, b) to f) shows the XPS analysis for carbon samples where it can be observed the C-C (sp2) at 284.6eV, CO/COH at 286.3 eV, COO at 289 eV and a broad peak of π- π* at 291 eV [1-2]. Figure S1. XPS C1s of the five samples of CNx. Electronic Supplementary Material (ESI) for Nanoscale. This journal is © The Royal Society of Chemistry 2019