Integration of Copper(II)-Porphyrin Zirconium Metal–Organic Framework and Titanium Dioxide to Construct Z-Scheme System for Highly Improved Photocatalytic CO₂ Reduction

Abstract

Acquiring stable photocatalysts in possession of efficacious CO 2 adsorption capacity and high charge-separation efficiency is crucial for carbon dioxide (CO 2 ) photoreduction into fossil resources. Hereby, via a direct integration of copper(II)-porphyrin zirconium metal−organic framework (PCN-224(Cu)) and TiO 2 nanoparticles, we establish an efficacious photocatalytic system capable of greatly enhancing the catalytic activity of TiO 2 in CO 2 photoreduction. In the absence of either cocatalyst or sacrifice reagent, CO evolution rate can reach up to 37.21 μmol g −1 h −1 , ca. 10 and 45.4 times that of mere PCN-224(Cu) (3.72 μmol g −1 h −1 ) and pure TiO 2 (0.82 μmol g −1 h −1 ), respectively. There are two contributors making devotion to the melioration of the catalytic activity. One is the augmented ability of light-harvesting given by the integrated metalloporphyrin-based MOF. The other is due to the conjunction between the MOF and TiO 2 , which constructs a Z-Scheme mechanism favoring beneficial promotion on the separation of photoexcited charges. This study provides theoretical support for meliorating photocatalytic performance through the combination of metalloporphyrin-based MOF and other inorganic semiconductors.

Photosensitive Hybrid Nanostructured Materials: The Big Challenges for Sunlight Capture

“…Furthermore, their huge surface area and tunable pore size and distribution promote substrate-catalyst interaction, providing at the same time size and shape selectivity towards the desired reaction [1,214,215]. Owing to these superior features, MOFs arise great interest in many photocatalytic processes, including hydrogen evolution [216][217][218], CO 2 reduction [175,[219][220][221], and pollutant degradation [222][223][224], as well as organic selective oxidations [225]. In most MOFs, inorganic metal nodes are the active component towards photo-redox reactions, exhibiting photoelectronic properties, typical of inorganic semiconductors (Figure 10a), yet with the better photocatalytic performance [1].…”

“…Another valid approach to reduce charge recombination rate and improve MOFs photocatalytic performance is based on their coupling with semiconductor nanoparticles, such as TiO 2 , ZnO, CdS, C 3 N 4 [255]. Cu(II)-porphyrin and TiO 2 nanoparticles into MOF structure (PCN-224(Cu)) leads to a marked improvement of light-harvesting features and promotes separation of photogenerated charges, reaching superior photocatalytic performance for CO 2 reduction [219,256]. Also, composites or heterostructures of titanium oxide or titanate fibers and MOFs, such as TiO 2 @NH 2 -MIL-88B(Fe), disclose high photocatalytic activity [257][258][259].…”

“…Actually, most of the previously described systems can be efficiently combined into a nanocomposite featuring direct Z-scheme heterojunction. Notably, some of them, such as carbon-based materials (graphene oxide, reduced graphene oxide, and especially graphitic carbon nitride) and MOFs, can act as electron mediators required in a solid-state Z-scheme mechanism [219,[328][329][330][331].…”

Fabrication of a novel BiOI/KTaO3 p–n heterostructure with enhanced photocatalytic performance under visible-light irradiation

“…[1][2][3][4] Although the TiO 2 semiconductor has attracted worldwide attention owing to its low price, nontoxicity and good stability against photocorrosion, [5][6][7] it can only capture ultraviolet (UV) light due to its relatively large bandgap ($3.2 eV). 8,9 UV light only comprises $4% of the solar spectrum, while the visible light makes up the greater part of sunlight. 10 Thus, more and more visible-light-driven photocatalysts have been designed and synthesized to maximize the sunlight utilization efficiency, such as a-Fe 2 O 3 , 11 Bi 2 MoO 6 , 12 Ag 3 PO 4 (ref.…”

Bimetallic Metal‐Organic Framework Derived ZnO/Ni0.9Zn0.1O Nanocomposites for Improved Photocatalytic Degradation of Organic Dyes

“…At present, numerous metal oxides such as ZnO, CdS, TiO 2 , Bi 2 O 3 , and Fe 2 O 3 , have been investigated for their photocatalytic activities. Besides them, nickle oxide (NiO) is also a promising photocatalyst because of its characteristics of low cost, innocuity, high hole mobility, and high photosensitivity .…”