Engineering of PMo12@NiCo-LDH composite via in situ encapsulation-reassembly strategy for highly selective photocatalytic reduction of CO2 to CH4

• Published in: Inorganic chemistry frontiers 2023-02, Vol.10 (5), p.1421-1430
• Main Authors: Zhang, Huaiying, Cui, Dongyuan, Shen, Tianyang, He, Tong, Sun, Danzhong, An, Sai, Qi, Bo, Yu-Fei, Song
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Composite materials; Encapsulation; Hydroxides; Intermetallic compounds; Light irradiation; Methane; Photocatalysis; Polyoxometallates; Reduction; Selectivity; Synergistic effect
• ISSN: 2052-1545; 2052-1553
• DOI: 10.1039/d2qi02325c

Polyoxometalate intercalated layered double hydroxide (POM-LDH) composites have drawn wide attention due to their tunable intrinsic properties, variable composition, and synergistic effects between LDHs and POMs. Herein, we report the fabrication of PMo12@NiCo-LDH composite via an in situ encapsulation-reassembly strategy using PMo12@ZIF-67 as the precursor, in which ZIF-67 was in situ converted to the corresponding NiCo-LDH in the presence of Ni(NO3)2 solution, and PMo12 was confined within the NiCo-LDH nanocages. When applied for the photocatalytic reduction of CO2 (CO2PR), the PMo12@NiCo-LDH composite exhibited excellent CH4 selectivity of 86.2% (production rate of 2.01 μmol h−1) and suppressed H2 selectivity of only 3.3% under visible light irradiation (λ > 500 nm). Such excellent performance can be attributed to the following reasons: (1) PMo12@NiCo-LDH modulated the band structure and promoted the efficient generation, transfer, and separation of photo-induced electron–hole pairs; (2) the presence of the crucial intermediates CH3O* and CHO* facilitated the generation of CH4. Moreover, PMo12@NiCo-LDH composites could be recycled for at least five cycles without an obvious decrease in catalytic performance, benefitting from the stable confinement of PMo12 within NiCo-LDH nanocages.