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Single-Atoms on Crystalline Carbon Nitrides for Selective C―H Photooxidation: A Bridge to Achieve Homogeneous Pathways in Heterogeneous Materials

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da Silva, Marcos A. R. ; Tarakina, Nadezda V. ; Filho, Jose B. G. ; Cunha, Carla S. ; Rocha, Guilherme F. S. R. ; Diab, Gabriel A. A. ; Ando, Romulo Augusto ; Savateev, Oleksandr ; Agirrezabal-Telleria, Iker ; Silva, Ingrid F. ; Stolfi, Sara ; Ghigna, Paolo ; Fagnoni, Maurizio ; Ravelli, Davide ; Torelli, Piero ; Braglia, Luca ; Teixeira, Ivo F.
Total Authors: 17
Document type: Journal article
Source: Advanced Materials; v. 35, n. 52, p. 13-pg., 2023-11-20.
Abstract

Single-atom catalysis is a field of paramount importance in contemporary science due to its exceptional ability to combine the domains of homogeneous and heterogeneous catalysis. Iron and manganese metalloenzymes are known to be effective in CH oxidation reactions in nature, inspiring scientists to mimic their active sites in artificial catalytic systems. Herein, a simple and versatile cation exchange method is successfully employed to stabilize low-cost iron and manganese single-atoms in poly(heptazine imides) (PHI). The resulting materials are employed as photocatalysts for toluene oxidation, demonstrating remarkable selectivity toward benzaldehyde. The protocol is then extended to the selective oxidation of different substrates, including (substituted) alkylaromatics, benzyl alcohols, and sulfides. Detailed mechanistic investigations revealed that iron- and manganese-containing photocatalysts work through a similar mechanism via the formation of high-valent MO species. Operando X-ray absorption spectroscopy (XAS) is employed to confirm the formation of high-valent iron- and manganese-oxo species, typically found in metalloenzymes involved in highly selective CH oxidations. Low-cost iron and manganese single-atoms are stabilized on poly(heptazine imides) (PHI). The resulting materials are exploited as photocatalysts for the selective oxidation of toluene into benzaldehyde, and further applied to the conversion of alkylaromatics and benzyl alcohols into the corresponding carbonyl derivatives. Operando X-ray absorption spectroscopy supports the intermediacy of metal-oxo species under heterogeneous conditions.image (AU)

FAPESP's process: 20/14741-6 - Graphitic carbon nitrides as platforms for single-atom photocatalysis: moving towards design principles for improved performance
Grantee:Ivo Freitas Teixeira
Support Opportunities: Research Grants - Young Investigators Grants
FAPESP's process: 22/16273-5 - Single atom supported on graphitic carbon nitrides towards biomass-based products valorization
Grantee:Guilherme de Freitas Silva Rodrigues Rocha
Support Opportunities: Scholarships abroad - Research Internship - Master's degree
FAPESP's process: 21/12394-0 - Sustainable synthetic methods employing catalysis, benign solvents, safer reagents, and bio-renewable feedstock
Grantee:Arlene Gonçalves Corrêa
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 21/13271-9 - Single atoms coordinated on graphitic carbon nitrides to photocatalytic conversion of methane
Grantee:Marcos Augusto Ribeiro da Silva
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 21/11162-8 - Multi-user equipment approved in grant 2020/14741-6: GC-MS/FID/TCD (2 injetores+Loop+Sistema valvulado)
Grantee:Ivo Freitas Teixeira
Support Opportunities: Multi-user Equipment Program