Ambient Photocatalytic Conversion of Atmospheric CO₂ and H₂O to Polyoxymethylene Via a Redox-Active Titanium-Phenanthroline Matrix

A light-driven, ambient-temperature pathway is described for converting atmospheric CO₂ and water directly into polyoxymethylene-type (POM) oligomers containing up to ~30-CH₂O-units, enabled by a hydrolyzed titanium(IV) chloride-1,10-phenanthroline (phen) matrix. Spontaneous hydrolysis of phen•TiCl₄ by trace water generates a disordered but catalytically competent ensemble of Ti-oxo, Ti-hydroxy, Ti-Cl, and phen-supported species. Water plays a dual role, initiating hydrolytic assembly of redox-active titanium clusters while supplying the protons and oxygen incorporated during CO₂ activation and chain propagation. nucleophilic attack by Ti-bound hydroxyls or oligomer termini, enabling sequential CH₂O insertion and controlled POM growth. MALDI-TOF mass spectra display regular m/z spacing corresponding to CH₂O extension, supported by ¹H/¹³C NMR and FTIR signatures of hydroxyl-terminated acetal chains HCOO-(CH₂-O)-H. These results establish a radical-driven, acetal-forming mechanism that integrates CO₂ capture, reduction, and polymer construction directly from atmospheric inputs under visible light.