Linker-Modulated Peroxide Electrosynthesis Using Metal-Organic Nanosheets

The electrochemical synthesis of hydrogen peroxide (H2O2), a widely used oxidant, is emerging as a green alternative to the conventional anthraquinone method. In this work, Ni-based metal-organic nanosheet (Ni-MON) catalysts constructed using a variety of linkers were studied as oxygen reduction catalysts. Using a host of analytical techniques, we reveal how modulating the terephthalic acid linker with hydroxy, amine, and fluorine groups impacts the resulting physical and electronic structure of the Ni catalytic sites. These changes further impact the catalysts' Faradaic Efficiency for H2O2, with the Ni-Amine-MON reaching near 100 % FE at minimal overpotential for the 2e(-) H2O2 pathway in alkaline electrolyte. Finally, we translate the Ni-Amine-MON catalyst to a gas-diffusion reaction geometry and demonstrate a H2O2 partial current density of 200 mA/cm(2) while maintaining 85 % Faradaic efficiency. In all, this study puts forth a simple route to catalyst modulation for highly effective H2O2 electrosynthesis.

Automated summary

In this study, Ni-based metal-organic nanosheets (Ni-MON) were used as oxygen reduction catalysts for electrochemical synthesis of hydrogen peroxide (H2O2). The physical and electronic structure of the Ni catalytic sites were modulated by changing the composition of the linker, such as introducing hydroxy, amine, and fluorine groups. The Ni-Amine-MON catalyst showed near 100% Faradaic efficiency for H2O2 in alkaline electrolyte. The catalyst was also successfully applied in a gas-diffusion reaction geometry, achieving a H2O2 partial current density of 200 mA/cm(2) while maintaining 85% Faradaic efficiency.