New pentametallic <scp>MnNiCoCu</scp> / <i>X</i> ( <i>X</i>  = Al, Fe) layered double hydroxides and their hybrids with Keggin‐type polyoxometalates for <scp>CO</scp> ₂ capture

Abstract BACKGROUND Carbon dioxide is a greenhouse gas that significantly influences global warming and climate change. Consequently, developing new materials that exhibit high adsorption capabilities, high regeneration efficiency, mild regeneration conditions, economic viability, and low operational costs for industrial applications is important. This study aimed to develop two novel pentametallic MnNiCoCu/ X ( X = Al, Fe) layered doubled hydroxides (LDHs) and their hybrids with polyoxometalates (POMs) through the hydrothermal technique, to achieve effective CO 2 capture. RESULTS The results revealed that two new pentametallic MnNiCoCu/Al LDH ( L1 ) and MnNiCoCu/Fe LDH ( L2 ), as well as their hybrids with Keggin‐type POMs (PW 12 O 40 3− ) ( L1α and L2β ), have been formed in the solid. Structural characterization using Fourier transform infrared spectroscopy, powder X‐ray diffraction, and field emission scanning electron microscopy–energy‐dispersive X‐ray spectroscopy revealed the presence of the pentametallic component in the LDH structure and its change after hybrid formation. The surface area of all solids ranged from 11.69 to 94.45 m 2 g −1 , with pore volumes from 0.025 to 0.075 cm 3 g −1 ; pore widths were from 3.19 to 9.36 nm, and were influenced by the presence of Al 3+ or Fe 3+ in the pentametallic layered and Keggin ion in the solid. All solids exhibited a porous morphology characterized by the arrangement of crystallites. The particle size of all solids ranged from 40.21 to 80.23 nm. The LDHs and their hybrids revealed a significant quantity of strong basic sites, rendering them suitable for CO 2 capture. We observed that the different trivalent ions (Al 3+ and Fe 3+ ) in the pentametallic LDH structure and their hybrids influenced the properties and capacity of CO 2 capture. CONCLUSION Two new pentametallic MnNiCoCu/ X ( X = Al, Fe) LDHs and their hybrids with POMs have significant potential for CO 2 capture applications. © 2025 Society of Chemical Industry (SCI).