Bioinspired metal complexes as electrocatalysts for hydrogen evolution: a systematic review

The expanding environmental impact resulting from our dependence on fossil fuels is driving the search for sustainable alternatives for energy production. In this context, the hydrogen evolution reaction (HER), especially through the electrolysis of water, has emerged as a promising route for obtaining green hydrogen. This study presents a systematic review, according to the PRISMA guidelines, on electrocatalysts based on bioinspired metal complexes applied to HER. The search was carried out in the Web of Science database, resulting in a detailed analysis of 40 articles. Structural aspects of the catalysts, experimental conditions, electrochemical techniques and performance parameters such as overpotential, turnover frequency (TOF), faradaic efficiency and stability were investigated. The bioinspired complexes analysed include mononuclear, heterobimetallic and hybrid architectures, employing metals such as Co, Fe, Ni, Mo and W, with various ligands and supports. The results indicate that specific structural combinations can confer high catalytic activity, even with low overpotentials (<200 mV), and stability of more than 100 hours of continuous operation. The conclusion is that the engineering of bioinspired metal complexes represents a promising strategy in electrochemical catalysis for HER, but it requires integrated and multidisciplinary approaches, with greater methodological standardization and advances in the characterization of stability and selectivity under realistic conditions.