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

Formaldehyde (CHO) 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 CHO 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 CHO 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 CHO. Notably, this synergy between Ni dual atoms activates CHO by strong chemical adsorption, thereby reducing the energy barrier of CHO oxidation and achieving the complete oxidation of CHO to CO. 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 CHO oxidation over CTF-2Ni are proposed. This work offers novel insights into the rational design of photocatalysts for CHO oxidation through the integration of Ni dual atoms into CTFs.