A team of researchers at the State University of Campinas (UNICAMP) has found a simple yet effective way to boost the performance of low-cost materials by deliberately introducing structural defects.
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In a recent study published in Electrochimica Acta, scientists from the Center for Innovation on New Energies (CINE) significantly enhanced the efficiency of inexpensive catalysts by engineering vacancies, or “defects,” into their structure. The approach offers a cost-effective route to improve materials used in hydrogen production.
CINE, established in 2018 through a partnership between FAPESP and Shell, operates across several Brazilian institutions, including UNICAMP, the University of São Paulo (USP), and the Federal University of São Carlos (UFSCar).
Hydrogen production through water splitting powered by renewable energy is currently the cleanest and most sustainable method available. However, the process involves two simultaneous reactions - hydrogen and oxygen evolution - with the oxygen reaction being notably slower.
Catalysts play a critical role here, especially for oxygen evolution, but they currently account for 20–30 % of hydrogen production costs. This makes the development of efficient, low-cost catalysts a major scientific priority.
The researchers focused on a class of materials known as Prussian blue analogs. These compounds, made from metal atoms and cyanide groups, are inexpensive and composed of earth-abundant elements. Their main limitation lies in the low number of active catalytic sites.
To address this, the UNICAMP team used an electrochemical technique to selectively remove cyanide groups, thereby creating vacancies within the material.
It may appear unusual, but these 'defects' resulting from vacancies can actually be quite beneficial. The material's structure undergoes slight alterations, leading to the formation of additional active sites where significant chemical reactions can take place more readily.
Juliano Bonacin, Study Lead, CINE Researcher and Professor, Institute of Chemistry (IQ-UNICAMP)
When tested as catalysts for the oxygen evolution reaction, the modified materials showed substantial improvement. A version of the catalyst with 30 % more structural defects produced 32 % more oxygen than the unmodified one.
The team also used advanced techniques at the Brazilian National Synchrotron Light Laboratory (LNLS), part of the Brazilian Center for Research in Energy and Materials (CNPEM), to better understand the mechanisms behind this improvement.
Bonacin notes that while the results are promising, the catalysts have yet to be tested outside the lab.
Although there’s still a way to go, the results obtained indicate a concrete and viable advance toward cheaper and more sustainable industrial technologies.
Juliano Bonacin, Study Lead, CINE Researcher and Professor, Institute of Chemistry (IQ-UNICAMP)
Journal Reference:
Germscheidt, R, L., et al. (2025) Electrochemical generation of unconventional cyanide vacancies to boost the catalytic performance of Co-Prussian Blue on oxygen evolution reaction under mild conditions. Electrochimica Acta. DOI: 10.1016/j.electacta.2025.146327. https://www.sciencedirect.com/science/article/abs/pii/S0013468625006887