New biocatalyst could more efficiently split water molecules

Experiment carried out on Sirius shed light on reaction fundamental to the production of hydrogen fuel

A recent experiment at Sirius, the Brazilian synchrotron light source at the Brazilian Center for Research in Energy and Materials (CNPEM) in Campinas, São Paulo (see Pesquisa FAPESP issue 269) showed how a certain biological catalyst can more efficiently split water molecules (H2O) using electrolysis. This reaction, an electrochemical process that uses electricity to break down water into the elements that comprise it, is very significant because it produces not only oxygen but also hydrogen, considered the fuel of the future by many specialists because it does not emit any polluting gases when it is utilized (see Pesquisa FAPESP issue 314).

“We discovered that when some enzymes present in nature like bilirubin oxidase (BOD) are manipulated in the lab, they can accelerate the reaction to split water,” states chemist Frank Nelson Crespilho, a professor at the University of São Paulo’s São Carlos Institute of Chemistry (IQSC-USP) who led the study. “We didn’t know why this happened; thanks to new equipment developed specifically for Sirius, we were able to observe how this enzyme, BOD, behaves during the process of oxidation in water. We found that the copper atoms within it are relevant to this reaction.”

Crespilho expects this advance to pave the way for science to get inspiration from the part of the enzyme that accelerated the reaction. “It is important for us to recognize the important regions of BOD, since today synthetic chemists that work in materials production can copy and synthesize this part of the enzyme in the laboratory. This will make the catalyst much more affordable, with a much broader range of potential applications,” he adds. Most of the catalysts used in this process utilize noble metals like platinum and iridium, making large-scale application unfeasible due to the cost involved. An article describing the experiment written by Crespilho’s team, which includes the researchers Graziela Sedenho, Rafael Colombo, Thiago Bertaglia, and Jessica Pacheco, was published in October in the journal Advanced Energy Materials. Scientists from the Brazilian Synchrotron Light National Laboratory (LNLS) also participated in the study.

Read more on the LNLS website

Image: Researcher manipulates electrochemical cell used in experiment