Converting Organic Wastewater into CO Using MOFs-Derived Co/In₂O₃ Double-Shell Photocatalyst

Abstract

The photocatalytic conversion of organic wastewater into value-added chemicals is a promising strategy to solve the environmental issue and energy crisis. Herein, Co/In 2 O 3 nanotubes with a double-shell structure, as a highly efficient photocatalyst, are synthesized by a one-step calcination method. The Co/In 2 O 3 heterostructure shows an outstanding photocatalytic CO 2 reduction performance of 4902 μmol h −1 g −1 . Notably, these Co/In 2 O 3 photocatalysts also achieve CO 2 self-generation and in situ reduction conversion in acid organic wastewater (phenol solution), in which the high CO 2 (47.5 μmol h −1 g −1 ) and CO (0.9 μmol h −1 g −1 ) evolution rates are demonstrated under solar irradiation. Transient photovoltage (TPV) tests demonstrate that Co nanoparticles on Co/ In 2 O 3 double-shell heterostructure serve as the CO 2 reduction sites for the effective capture and stabilization of the photogenerated electrons.

Replacing Ru complex with carbon dots over MOF-derived Co3O4/In2O3 catalyst for efficient solar-driven CO2 reduction

“…45 The Co 2p peaks of CDs-M-CIO at 781.5 eV (Co 2+ 2p 3/2 ) and 796.6 eV (Co 2+ 2p 1/2 ) shift to higher binding energies, probably due to electrons deviated from M-Co 3 O 4 caused by the intimate interface of the CDs-M-CIO heterojunction. 20,46 As shown in Fig. 2l, the O 1s spectrum of M-In 2 O 3 can be fitted by three peaks at 529.7, 531.2 and 532.4 eV, attributable to In–O lattice oxygen (O L ), oxygen vacancies (O V ) and surface-bound hydroxyls (O OH ), respectively, and the peaks of M-Co 3 O 4 are located at 530 eV (O L ), 531.3 eV (O V ) and 533.0 eV (O OH ).…”

“…After introduction of CDs, the peaks of the CDs-M-CIO composite are at 604 cm −1 (In–O), 658 cm −1 (Co–O), 1400 cm −1 (C–O–C) and 1630 cm −1 (CO), and the peaks of the CDs in the composite are shifted slightly compared with pristine CDs, indicating the existence of interaction between the CDs and the binary metal oxides. 20…”

“…16–19 More recently, we reported that the [Ru(bpy) 3 ]Cl 2 modified metal oxide catalysts to effectively convert CO 2 into syngas. 20 However, these noble metal photosensitizers also suffer from high cost, complicated synthetic processes and low durability, which limit their large-scale catalytic applications.…”

In Situ Self-Assembled ZIF-67/MIL-125-Derived Co3O4/TiO2 p–n Heterojunctions for Enhanced Photocatalytic CO2 Reduction

“…27,28 In our previous work, the ZIF-67/MIL-68-derived Co/In 2 O 3 heterostructure indicates an excellent photocatalytic CO 2 reduction performance. 29 Benefiting from the unique MOF-on-MOF structure, MOF-derived metal oxide heterostructures can possess high-quality contact for better light utilization and appropriate band alignment at the p−n heterojunction interfaces. 30 Thus, we believe that the Co 3 O 4 / TiO 2 heterojunction originated from MOFs could have a strong interaction effect on the photocatalytic CO 2 reduction performance.…”

“…MOFs with porous coordination structures act as an ideal template to produce metal oxides or metal nanoparticles under an air or a N 2 atmosphere through one-step pyrolysis, which can inherit the original morphology of MOFs, provide plentiful active sites, and enhance the stability and electrical conductivity. , In our previous work, the ZIF-67/MIL-68-derived Co/In 2 O 3 heterostructure indicates an excellent photocatalytic CO 2 reduction performance . Benefiting from the unique MOF-on-MOF structure, MOF-derived metal oxide heterostructures can possess high-quality contact for better light utilization and appropriate band alignment at the p–n heterojunction interfaces .…”