Agradecimentos: The authors are grateful for the financial support of Brazilian Funding Agencies. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior?Brasil (CAPES)?Finance Code 001, Conselho Nacional de Desenvolvimento Científico e Tecnológico CNPq (grant# 308203/2021-6) and Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP (grant# 2014/50867-3, grant# 2017/11986-5, grant# 2017/50085-3, grant# 2018/25092-9, grant# 2018/25207-0, grant# 2019/00063-9, grant# 2019/2445-8, grant# 2021/05976-2). This research used facilities of the Brazilian Synchrotron Light Laboratory (LNLS), part of the Brazilian Center for Research in Energy and Materials (CNPEM), a private non-profit organization under the supervision of the Brazilian Ministry for Science, Technology, and Innovations (MCTI). The IPE beamline staff is acknowledged for the assistance during the experiments 20220865 Ver menos

Abstract: Prussian blue analogues are one of the most promising examples of water oxidation catalysts presenting great performance, activity, and stability under mild conditions. Herein, we report an alternative methodology to synthesize the Prussian blue, obtaining a catalyst with vacancies created by an electrochemical method. This catalyst showed an outstanding activity, with an onset overpotential of 361 mV. Using pyridine as a molecular probe, we identified the presence of vacant Fe2+ sites, and the quantification of these sites allowed us to estimate a TOF number of 0.2170 s–1 for the water oxidation reaction. These results indicate that defect engineering is a versatile strategy to boost the catalytic activity in Prussian blue analogues by increasing the number of active sites Ver menos