Complete Photooxidation of Formaldehyde to CO₂ via Ni-Dual-Atom Decorated Crystalline Triazine Frameworks: A DFT...

Formaldehyde (CH₂O) emerges as a significant air pollutant, necessitating effective strategies for its oxidation to mitigate adverse impacts on human health and the environment. Among various technologies, the photooxidation of CH₂O stands out owing to its affordability, safety, and effectiveness. Nitrogen-rich crystalline triazine-based organic frameworks (CTFs) exhibit considerable potential in this domain. Nevertheless, the weak and unstable CH₂O adsorption hinders the overall oxidation efficiency of CTF. To address this limitation, we incorporate single and dual Ni atoms into nitrogen-rich CTFs by density functional theory (DFT) calculations, resulting in CTF-Ni and CTF-2Ni. This strategic modification significantly enhances the adsorption capability of CH₂O. Notably, this synergy between Ni dual atoms activates CH₂O by strong chemical adsorption, thereby reducing the energy barrier of CH₂O oxidation and achieving the complete oxidation of CH₂O to CO₂. Moreover, the introduction of dual-atom Ni over CTF ameliorates visible and near-infrared light absorption and facilitates photoexcited charge transfer and separation. Finally, the underlying mechanisms of complete CH₂O oxidation over CTF-2Ni are proposed. This work offers novel insights into the rational design of photocatalysts for CH₂O oxidation through the integration of Ni dual atoms into CTFs.