A series of chromium oxides (Cr2O3) nanoparticles supported on different carbonaceous material, namely: graphene, graphene oxide (GO) and graphite, were synthetized by precipitation of the salt precursors with precipitant (ammonia) and the subsequent thermal treatment. The catalytic activity of these composites and the Cr2O3 nanoparticles have been analysed by Koutecky-Levich (KL) and rotating ring-disc electrode methods and the results have been discussed following a model proposed here, which considers the O2 electrosorption as the rate determining step. Among them, graphite and graphene based composites have better catalytic activities and their behaviours agree with the proposed treatment: logarithm dependent of the intercept and nondependent slopes values of the KL plots with the potential. Cr2O3-graphite shows a mechanism interchanging 4 e-, which has been attributed to a graphite- Cr2O3 nanoparticles interaction. Besides, Cr2O3-graphite-based electrodes have been tested as cathode in a Zn/PVA-KOH/air battery, confirming its good properties to be applied as positive electrode in metal-air batteries.The authors thank the financial support from Fundación Séneca (Región de Murcia, Spain; Ref: 20985/PI/18), Spanish Agencia Estatal de Investigación (PID2019-104272RB-C55/AEI/10.13039/501100011033, CTQ2017-90659-REDT and PID2019-106097 GB/AEI/10.13039/501100011033), MINECO (projects MAT2017-84118-C2-2-R and MAT2017-82252-R) and Banco Santander-UCM (project PR87/19-22613). The authors also acknowledge Victor Galindo Garre for providing R-Studio scripts for data analysis
