Autor(es): Silva, Ana Luísa ; Esteves, Laura M. ; Silva, Ludmila P.C. ; Ramos, Vítor S. ; Passos, Fábio B. ; Carvalho, Nakédia M. F.
Data: 2022
Identificador Persistente: http://hdl.handle.net/10362/150657
Origem: Repositório Institucional da UNL
Assunto(s): Chemistry(all); Chemical Engineering(all)
Funding Information: This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (BR) - CNPq [PQ-2/2018: 313831/2018-1], Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro - FAPERJ [JCNE 2018: E-26/203.023/2018; Apoio às Universidades Estaduais: E-26/010.101141/2018; Projetos Temáticos: SEI-260003/001198/2020; PD10 2020: E-26/290.125/2020 post-doctoral Scholarship], and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) [Finance Code 001]. The authors would like to acknowledge NANOFAB/UERJ for the SEM measurements, LCM/CAIPE-UFF for the Raman analyses, G2E-UFF for the RDE electrode, LACES-UFRJ for the thermogravimetric analysis, Multiuser Laboratory of Pontal at the Federal University of Uberlândia for the ASAP analyses (FINEP/2013 INFR13 01.13.0371.00), and LCS/LNNano-CNPEM for the use of AFM in its open facilities. Publisher Copyright: © 2022 The Royal Society of Chemistry.
This work reports the application of Mn-doped Co3O4 oxides in the electrocatalytic oxygen evolution reaction (OER). The materials were characterized by structural, morphological, and electrochemical techniques. The oxides with higher Co : Mn molar ratio presented a lower electron transfer resistance, and consequently the most promising OER activities. Pure Co3O4 shows an overpotential at j = 10 mA cm−2 of 761, 490, and 240 mV, at pH 1, 7, and 14, respectively, and a high TOF of 1.01 × 10−1 s−1 at pH 14. Tafel slopes around 120 mV dec−1 at acidic pH and around 60 mV dec−1 at alkaline pH indicate different OER mechanisms. High stability for Co3O4 was achieved for up to 15 h in all pHs, and no change in the structure and morphology after the electrocatalysis was observed. The reported excellent OER activity of the Mn-Co oxides in a wide pH range is important to broaden the practical applicability in different electrolyte solutions.
