CNR ExploRA

Articolo in rivista, 2023, ENG, 10.1021/jacs.3c03785

An Atomically Dispersed Mn-Photocatalyst for Generating Hydrogen Peroxide from Seawater via the Water Oxidation Reaction (WOR)

Peng Ren, Tong Zhang, Noopur Jain, H. Y. Vincent Ching, Aleksander Jaworski, Giovanni Barcaro, Susanna Monti, Joaquin Silvestre-Albero, Veronica Celorrio, Lata Chouhan, Anna Rokici?ska, Elke Debroye, Piotr Ku?trowski, Sabine Van Doorslaer, Sandra Van Aert, Sara Bals, and Shoubhik Das

Department of Chemistry, University of Antwerp, Antwerp 2020, Belgium; EMAT and NANOlab Center of Excellence, Department of Physics, University of Antwerp, Antwerp 2020, Belgium; Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 10691, Sweden; CNR-IPCF, Institute for Chemical and Physical Processes, Area della Ricerca, Pisa I-56124, Italy; CNR-ICCOM, Institute of Chemistry of Organometallic Compounds, Area della Ricerca, Pisa I-56124, Italy; Departamento de Química Inorgánica, Universidad de Alicante, Alicante E-03080, Spain; Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K.; Department of Chemistry, KU Leuven, Leuven 3001, Belgium; Department of Chemical Technology, Jagiellonian University, Krakow 30-387, Poland;

In this work, we have fabricated an aryl amino-substituted graphitic carbon nitride (g-C3N4) catalyst with atomically dispersed Mn capable of generating hydrogen peroxide (H2O2) directly from seawater. This new catalyst exhibited excellent reactivity, obtaining up to 2230 ?M H2O2 in 7 h from alkaline water and up to 1800 ?M from seawater under identical conditions. More importantly, the catalyst was quickly recovered for subsequent reuse without appreciable loss in performance. Interestingly, unlike the usual two-electron oxygen reduction reaction pathway, the generation of H2O2 was through a less common two-electron water oxidation reaction (WOR) process in which both the direct and indirect WOR processes occurred; namely, photoinduced h+ directly oxidized H2O to H2O2 via a one-step 2e- WOR, and photoinduced h+ first oxidized a hydroxide (OH-) ion to generate a hydroxy radical (oOH), and H2O2 was formed indirectly by the combination of two oOH. We have characterized the material, at the catalytic sites, at the atomic level using electron paramagnetic resonance, X-ray absorption near edge structure, extended X-ray absorption fine structure, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, magic-angle spinning solid-state NMR spectroscopy, and multiscale molecular modeling, combining classical reactive molecular dynamics simulations and quantum chemistry calculations.

Journal of the American Chemical Society (Online) 145 (30), pp. 16584–16596