@misc{10481/105579,
year = {2025},
month = {5},
url = {https://hdl.handle.net/10481/105579},
abstract = {The development of bifunctional ORR and OER electrocatalysts is fundamental to the application of electrochemical energy conversion devices (e.g. fuel cells). However, these electrocatalysts must be sustainable and cost-effective. Herein, we prepared several shrimp shells-derived biochars (directly obtained from the pyrolysis – CC; obtained by pretreatment before pyrolysis: hydrothermal carbonization - CCh and acid washing- CCw), which were simultaneously doped with N and decorated with Co nanoparticles via wet impregnation followed by pyrolysis. The resulting composites (Co/N-CC, Co/N-CCh and Co/N-CCw) presented distinct physical-chemical properties, as assessed by ICP-OES, SEM, N2 adsorption-desorption isotherms, Raman spectroscopy, XRD and XPS. While the biochar support used had an important effect on composite electrocatalytic activity, in general, the introduction of N functionalities and Co nanoparticles led to enhanced ORR and OER performances. The effect of the pyrolysis temperature during the doping/Co incorporation procedure was also evaluated on the most promising biochar support (CC) and the resulting composite Co/N-CC_600 displayed enhanced performance towards both reactions, as it led to higher content of pyridinic-N, graphitic-N and N coordinated to Co, higher degree of graphitization and more exposed active sites. Indeed, it achieved comparable E1/2 to Pt/C (0.79 V vs. RHE), Eonset of 0.85 V vs. RHE, jL of −3.80 mA cm−2, nO2 of 3.29 and TS of 52 mV dec−1 for ORR. In OER, it presented similar η10 and TS (0.48 V and 79 mV dec−1, respectively) to benchmark IrO2. Moreover, the electrocatalyst showed excellent stability for ORR and a moderate current retention in OER.},
organization = {FCT/MCTES (EXPL/BII-BIO/0436/2021)},
organization = {Associado para a Química Verde - Tecnologias e Processos Limpos (10.54499/LA/P/0008/2020, 10.54499/UIDP/50006/2020
and 10.54499/UIDB/50006/2020)},
organization = {Individual Call to Scientific Employment Stimulus (Refs. 2021.00771.CEECIND/CP1662/CT0007, 10.54499/2021.00771; CEECIND/CP1662/CT0007 and 2020.01614.CEECIND/CP1596/
CT0007, 10.54499/2020.01614.CEECIND/CP1596/CT0007)},
organization = {Junta de Andalucía (PAIDI 2020, Young Doctors Program)},
publisher = {Elsevier},
keywords = {Biomass},
keywords = {Shrimp shell},
keywords = {Cobalt},
keywords = {ORR},
keywords = {OER},
title = {The role of biochar pretreatment on the ORR and OER electrocatalytic performance of nitrogen-doped biochars decorated with cobalt},
doi = {10.1016/j.ijhydene.2025.05.167},
author = {Matos, Renata and Marques, Inês S. and Fernandes, António J.S. and Abdelkader Fernández, Víctor Karim and F. Peixoto, Andreia and Fernandes, Diana M.},
}