Single-Atom Fe Triggers Superb CO₂ Photoreduction on a Bismuth-Rich Catalyst

Abstract

Insufficient separation of photogenerated electron−hole and feeble CO 2 activation remain the main obstacles in the access to high-performance CO 2 reduction nowadays. Single-atom active sites engineering could be an efficient method through simultaneously promoting charge separation and CO 2 activation. Herein, a model of Bi 4 O 5 I 2 with single-atom Fe implanting and accompanying Bi decorating on surface is proposed to boost the performance. The single-atom Fe implantation decreases the value of surface work function, allowing the fast transition of photon-generated electrons from the surface of catalyst to CO 2 molecule. In situ Fourier transform infrared (FT-IR) spectra, CO 2 adsorption measurements, density functional theory (DFT) calculations, and efficient CO 2 activation are realized on as-established singleatom catalyst. An exceptional yield of CO (23.77 μmol g −1 h −1 ) and CH 4 production (4.98 μmol g −1 h −1 ) is acquired over optimized Bi 4 O 5 I 2 −Fe30 with 1.09 wt % of singleatom Fe, superior to Bi 4 O 5 I 2 , and most other reported photocatalysts. The work paves a insight into rational design of photocatalysts toward simultaneously facilitating carrier separation and CO 2 activation from the angle of atom single metal.

Electronic Modulation of the Interaction between Fe Single Atoms and WO2.72–x for Photocatalytic N2 Reduction

“…The differential charge densities of Fe-SA/WO 2.72– x with N 2 adsorption clearly show that the N 2 molecule obtains electrons from WO 2.72– x and is activated (Figure e). In addition, the pictures of the electron localization function (ELF, Figure f,g) indicate that when the Fe single atom is anchored on the WO 2.72– x surface, there is delocalization of electrons across the Fe–O bond (Figure S13), which denotes high covalency favorable to the state transition of interfacial electrons and acceleration of charge transfer . The above results indicate that an electron transfer channel is created between the Fe-SA/WO 2.72– x surface and the adsorbed N 2 , enabling the Fe single atom to be the active site for N 2 activation.…”

Considering single-atom catalysts as photocatalysts from synthesis to application

“…For instance, Jin et al. proposed SAPs with Fe SAs implanted into the surface of Bi 4 O 5 I 2 (Bi 4 O 5 I 2 -Fe30) ( Jin et al., 2021 ). As such, Fe SAs were considered as the dopant to replace the Biatoms in Bi 4 O 5 I 2 , which generated impurity energy levels within the bandgap of Bi 4 O 5 I 2 , leading to a broadened light-harvesting range toward the Bi 4 O 5 I 2 -Fe30 SAPs.…”

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Figure 6 Effect of single-atom modification on the electronic structure of photocatalysts (A–I) Bi 4 O 5 I 2 and Bi 4 O 5 I 2 -Fe30 of (A) UV-Vis absorption spectra, (B) Tauc plot, (C) Mott-Schottky plots, (D) XPS valence band spectroscopy, (E) DFT calculation for the band structure, and (F) DOS plots. Reproduced with permission from Ref ( Jin et al., 2021 ). Copyright 2021, American Chemical Society.

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Bionic Optical Leaf for Photoreduction of CO2 from Noble Metal Atom Mediated Graphene Nanobubble Arrays

“…Huge efforts have been made worldwide to tackle the greenhouse effect from carbon emission. − Reduction of CO 2 , one of the major carbon emissions, to useful chemicals, such as CO, CH 4 , CH 3 OH, and HCOOH, has been of great interest in recent years. − Among the products, selective and highly efficient reduction of CO 2 to CO is of particular interest because of its favorable reaction kinetics in the reduction process and the value of CO in the chemical industries. , Typical photocatalysts used for CO 2 reduction, such as metal oxides and metal sulfides, could generate photoelectrons via photoirradiation because of the semiconductive properties; however, insufficient electron–hole separation and low light absorption volume still hinder their practical performance. − Though noble metal nanoparticles were introduced to boost the electron–hole separation efficiency of these nano-semiconductors, , the low utilization efficiency of noble metals still restricts their practical application. Compared with nanostructured semiconductors, carbon is abundant, excels in light absorption, and is usually used as a promoter in photocatalysts. , In recent years, the carbonaceous promoters for photocatalysts, especially graphene, have attracted a lot of interest because of their physical and chemical properties. − However, fine-tuning the electronic structure of graphene to effectively drive the photoreduction of CO 2 remains a challenge.…”

“…8,9 Typical photocatalysts used for CO 2 reduction, such as metal oxides and metal sulfides, could generate photoelectrons via photoirradiation because of the semiconductive properties; however, insufficient electron−hole separation and low light absorption volume still hinder their practical performance. 10−12 Though noble metal nanoparticles were introduced to boost the electron−hole separation efficiency of these nano-semi-conductors, 13,14 the low utilization efficiency of noble metals still restricts their practical application. Compared with nanostructured semiconductors, carbon is abundant, excels in light absorption, and is usually used as a promoter in photocatalysts.…”