AbstractAlkaline salt of platinum‐incorporated heteropolyoxoniobate [Pt(Nb₆O₁₉)₂]¹²⁻ (Pt(Nb6)2) was fabricated and applied for N‐formylation of various amines including piperidine under CO₂ and H₂ atmosphere. Pt(Nb6)2 achieved the selective formation of 1‐formylpiperidine, whereas the absence of Pt species, H₂, and CO₂ resulted in a trace amount of the product. The structural characterization revealed that the sandwich‐type structure of Pt(Nb6)2 was transformed into Pt nanoparticles incorporated with polyoxoniobates ([Nb₆O₁₉]⁸⁻) on the NbO_x bulk matrix (NbPOM‐PtNPs/NbO_x) under reaction conditions. The N‐formylation of amines in the presence of CO₂ and H₂ proceeded by the bifunctional NbPOM‐PtNPs/NbO_x where the basic sites of [Nb₆O₁₉]⁸⁻ and the redox property of Pt promoted the generation of formamides.