Sacrificial Reagents Research Articles

Unveiling Mechanistic Insight into Accelerating Oxygen Molecule Activation by Oxygen Defects in Co3O4-x/g-C3N4 p-n Heterojunction for Efficient Photo-Assisted Uranium Extraction from Seawater.

Photo-assisted uranium extraction from seawater (UES) is regarded as an efficient technique for uranium resource recovery, yet it currently faces many challenges, such as issues like biofouling resistance, low charge separation efficiency, slow carrier transfer, and a lack of active sites. Based on addressing the above challenges, a novel oxygen-deficient Co3O4-x/g-C3N4 p-n heterojunction is developed for efficient photo-assisted uranium extraction from seawater. Relying on the defect-coupling heterojunction synergistic effect, the redistribution of molecular charge density formed the built-in electric field as revealed by DFT calculations, significantly enhancing the separation efficiency of carriers and accelerating their migration rate. Notably, oxygen vacancies served as capture sites for oxygen, effectively promoting the generation of reactive oxygen species (ROS), thereby significantly improving the photo-assisted uranium extraction performance and antibacterial activity. Thus, under simulated sunlight irradiation with no sacrificial reagent added, Co3O4-x/g-C3N4 extracted a high uranium extraction amount of 1.08mgg-1 from 25 L of natural seawater after 7 days, which is superior to most reported carbon nitride-based photocatalysts. This study elaborates on the important role of surface defects and inerface engineering strategies in enhancing photocatalytic performance, providing a new approach to the development and design of uranium extraction material from seawater.

Rich Sulfur Vacancies and Reduced Schottky Barrier Height Synergistically Enable Au/ZnIn2S4 with Enhanced Photocatalytic CO2 Reduction into CO.

Constructing the plasmonic metal/semiconductor heterostructure with a suitable Schottky barrier height (SBH) and the sufficiently reliable active sites is of importance to achieve highly efficient and selective photocatalytic CO2 reduction into hydrocarbon fuels. Herein, we report Au/sulfur vacancy-rich ZnIn2S4 (Au/VSR-ZIS) hierarchical photocatalysts, fabricated via in situ photodepositing Au nanoparticles (NPs) onto the nanosheet self-assembled ZnIn2S4 (ZIS) micrometer flowers (MFs) with rich sulfur vacancies (VS). Density functional theory (DFT) calculations confirm that for the Au/VSR-ZIS system, the Au NPs serve as the reaction sites for H2O oxidation, and the VSR-ZIS MFs serve as those for CO2 reduction. The rich VS in the Au/VSR-ZIS hybrid can reduce its SBH so as to boost more hot electrons in the Au NPs across its Schottky barrier and then inject into the conduction band (CB) of the VSR-ZIS MFs. In addition, VS can also act as the electron sink to trap the photogenerated electrons, retarding the recombination of photogenerated carriers. The two merits effectively enhance the photogenerated electron density in the surface of VSR-ZIS MFs, availing CO2 photoreduction. In addition, the introduction of rich VS in the Au/VSR-ZIS hybrid can offer more active sites, benefiting the CO2 adsorption and accelerating the desorption of CO* from the surface of the photocatalyst. Therefore, under visible light illumination with no sacrificial reagent, the optimum photocatalyst (Au/VSR-ZIS-0.4) presents the enhanced and selective CO2 photoreduction into CO (8.15 μmol g-1h-1 and near 100%), which are superior to those of most of ZIS-based and plasmon-based photocatalysts. The photocatalytic activity is about 40.0-fold as high as that of the Vs-poor-ZIS (VSP-ZIS) MFs. This work contributes a viable strategy for designing highly efficient plasmonic photocatalysts by using the synergism of the anion vacancies and the optimized SBH induced by them.

Constructing multifunctional novel noble-metal free NiS/ZnS/g-C3N4 ternary nanocomposites for highly active superior photocatalytic water splitting

Ultrasound-assisted wet-impregnation approach and cation-exchange hydrothermal method are employed effectively to develop the ternary nanocomposites NiS/ZnS/g-C3N4 (NZ-CN) with promising photocatalytic hydrogen (H2) generation activity. Several analytical techniques are utilized to characterize the as-synthesized NiS/ZnS/g-C3N4 nanocomposites to study their physical and chemical characteristics. The H2 production activity of the synthesized photocatalysts was tested using a 250 W halogen lamp with Na2S (0.25 M) and Na2SO3 (0.35 M) as sacrificial reagents. The optimized NZ-CN7.5% (3% NiS/ZnS/7.5% g-C3N4) catalyst displayed an exceptional H₂ generation rate of 8624 μmol h⁻1 g⁻1, exceeding both, pristine g-C3N4 (by 22.1 times) and 3% NiS/ZnS (by 3 times). This represents the highest reported rate of H₂ evolution for a graphitic carbon nitride (g-C3N4) based ternary nanocomposite under simulated solar radiation. By reusing the used NZ-CN7.5% (3% NiS/ZnS/7.5% g-C3N4) photocatalyst in four consecutive runs, the stability of the catalyst was investigated, and their individual activity in the H2 production activity was assessed. This study provides valuable insights for designing efficient noble metal-free g–C3N4–based photocatalysts, which can significantly contribute to the transition to solar-driven hydrogen generation. Further, we proposed a plausible mechanism for the photocatalytic H2 generation process over the NiS/ZnS/g-C3N4 photocatalyst.

Poly(3‐hexylthiophene) film coated on plastic substrate as an organic photoanode for water oxidation/oxygen evolution with light illumination

AbstractPoly(3‐hexylthiophene) (P3HT) film was applied as a photoanode on an electron‐extracting layer‐coated upon a current‐collecting plastic substrate. The film soaked in an aqueous solution (pH 12) exhibited an enhanced anodic current with light illumination, and the photocurrent density (J) reached almost 100 μA/cm2 for its wound cylinder, which was accompanied by oxygen bubble evolution. The light ON/OFF response, light‐intensity proportion, and wavelength‐dependency of the J value supported the photo‐electrolytic function of the P3HT film. The hole‐injection efficiency of the film estimated for water oxidation using a solution involving a sacrificial reagent, was relatively high in the range of 46%–86%. Although an apparent activation energy of 39 kJ/mol for the electrolytic water oxidation in the dark suggested a chemical but catalytic pathway for the film anode, the temperature independence of the photocurrent indicated direct hole‐injection into water or hydroxide ions. The photoanode performance of the P3HT film for water oxidation was discussed in relation to the energy diagram including the highest occupied molecular orbital level.

WO3/BiOBr S-Scheme Heterojunction Photocatalyst for Enhanced Photocatalytic CO2 Reduction.

The photocatalytic CO2 reduction strategy driven by visible light is a practical way to solve the energy crisis. However, limited by the fast recombination of photogenerated electrons and holes in photocatalysts, photocatalytic efficiency is still low. Herein, a WO3/BiOBr S-scheme heterojunction was formed by combining WO3 with BiOBr, which facilitated the transfer and separation of photoinduced electrons and holes and enhanced the photocatalytic CO2 reaction. The optimized WO3/BiOBr heterostructures exhibited best activity for photocatalytic CO2 reduction without any sacrificial reagents, and the CO yield reached 17.14 μmol g-1 after reaction for 4 h, which was 1.56 times greater than that of BiOBr. The photocatalytic stability of WO3/BiOBr was also improved.

Healable multilayered photocatalysts promote durability and productivity of solar-driven CO2 conversion

Numerous studies have focused on efficient CO2 photoreduction on short notice. However, more hours of efficient and selective CO2 and pure water photoconversion without precious metals or sacrificing reagents should be emphasized. Herein, a multilayer (SrTiO3/Ce:CaF2/CuNi/Ce:CaF2/TiN) is utilized with a high selectivity of 87 % for healable photocatalytic CO2 and pure water conversion without sacrificial reagents and the longest service life for the Cu nanolayers, to the best of our knowledge. Meanwhile, the photocatalytic activity, optical absorption, and charge separation ability of SrTiO3/Ce:CaF2/CuNi/Ce:CaF2/TiN can be recovered after regeneration. The deactivation and healable mechanism are illuminated that the adsorption of CO2 molecules at the photocatalyst surface is changed from M-CO2 to MO-CO2, due to the oxidation of active sites, resulting in the deactivation of CO2 reduction. The Ce:CaF2 nanolayers can accommodate oxygen atoms effectively to heal the photocatalyst. The article proposes a feasible way for commercial CO2 and pure water photoconversion.

Photo-induced imine reduction by a photoredox biocatalyst consisting of a pentapeptide and a Ru bipyridine terpyridine complex

Imine reduction is a useful reaction in the preparation of amine derivatives. Various catalysts have been reported to promote this reaction and photoredox catalysts are promising candidates for sustainable amine synthesis. Improvement of this reaction using biomolecule-based reaction scaffolds is expected to increase the utility of the reaction. In this context, we have recently investigated photoredox Ru complexes with pentapeptide scaffolds via coordination bonds as catalysts for photoreduction of dihydroisoquinoline derivatives. First, Ru bipyridine terpyridine complexes coordinated with five different pentapeptides (XVHVV: X = V, F, W, Y, C) were prepared and characterized by mass spectrometry. Catalytic activities of the Ru complexes with XVHVV were evaluated for photoreduction of dihydroisoquinoline derivatives in the presence of ascorbate and thiol compounds as sacrificial reagents and hydrogen sources. Interestingly, the turnover number of the Ru complex with VVHVV is 531, which is two-fold higher than that of a simple Ru complex with an imidazole ligand. The detailed emission lifetime measurements indicate that the enhanced catalytic activity provided by the peptide scaffold is caused by an efficient reaction with the thiol derivative to accelerate reductive quenching of Ru complex. The quenching behavior suggests formation of an active species such as a Ru(I) complex. These findings reveal that the simple pentapeptide serves as an effective scaffold to enhance the photocatalytic activity of a photoactive Ru complex.

Halogen-functionalized covalent organic frameworks for photocatalytic Cr(VI) reduction under visible light

Covalent organic frameworks (COFs) are a type of novel organic catalysts which show great potential in the treatment of environmental contaminations. Herein, we synthesized three isoreticular halogen-functionalized (F, Cl and Br) porphyrin COFs for visible-light (420 nm ≤ λ ≤ 780 nm) photocatalytic reduction of Cr(VI) to Cr(III). Halogen substituents with tunable electronegativity can regulate the band structure and modulate the charge carrier kinetics of COFs. In the absence of any sacrificial reagent, the isoreticular COFs exhibited good photocatalytic reduction activity of Cr(VI). Particularly, the TAPP-2F showed nearly 100 % conversion efficiency and the highest reaction rate constants (k) on account of the strong electronegativity of F substituent. Experimental results and theoretical calculations showed that the conduction band (CB) potentials of COFs became more negative and charge carrier separation increased with the enhancement of electronegativity (Br < Cl < F), which could provide sufficient driving force for the photoreduction of Cr(VI) to Cr(III). The halogen substituents strategy for regulating the electronic structure of COFs can provide opportunities for designing efficient photocatalysts for environmental remediation. Meanwhile, the mechanistic insights reported in this study help to understand the photocatalytic degradation pathways of heavy metals.

Acceleration of Photoinduced Electron Transfer by Modulating Electronegativity of Substituents in Stable Zr-Metal-Organic Frameworks to Boost Photocatalytic CO2 Reduction.

Photoreduction of CO2 with water into chemical feedstocks of fuels provides a green way to help solve both the energy crisis and carbon emission issues. Metal-organic frameworks (MOFs) show great potential for CO2 photoreduction. However, poor water stability and sluggish charge transfer could limit their application. Herein, three water-stable MOFs functionalized with electron-donating methyl groups and/or electron-withdrawing trifluoromethyl groups are obtained for the CO2 photoreduction. Compared with UiO-67-o-CF3-CH3 and UiO-67-o-(CF3)2, UiO-67-o-(CH3)2 achieves excellent performance with an average CO generation rate of 178.0 μmol g-1 h-1 without using any organic solvent or sacrificial reagent. The superior photocatalytic activity of UiO-67-o-(CH3)2 is attributed to the fact that compared with trifluoromethyl groups, methyl groups could not only elevate CO2 adsorption capacity and reduction potential but also promote photoinduced charge separation and migration. These are evidenced by gas physisorption, photoluminescence, time-resolved photoluminescence, electrochemical impedance spectroscopy, transient photocurrent characteristics, and density functional theory calculations. The possible working mechanisms of electron-donating methyl groups are also proposed. Moreover, UiO-67-o-(CH3)2 demonstrates excellent reusability for the CO2 reduction. Based on these results, it could be affirmed that the strategy of modulating substituent electronegativity could provide guidance for designing highly efficient photocatalysts.

Optical Fiber-Enabled In Situ Photocatalytic Hydrogen Generation for Infiltrating Tumor Therapy in Brain.

In addition to repressing proliferation, inhibiting infiltration of tumor cells is an important strategy to improve the treatments of malignant tumors. Herein, a photocatalyst (pCNMC@Pt) is designed by sequentially assembling manganese dioxide, chlorin e6, and platinum (Pt) nanoparticles onto protonated graphitic carbon nitride. With the help of Z-scheme structure and near-infrared (NIR) photosensitizer, pCNMC@Pt is capable of responding to NIR light to generate large amounts of hydrogen (H2). Taking lactic acid in tumor microenvironment as sacrificial reagent, H2 therapy initiated by the NIR photocatalyst remarkably impedes the growth of glioblastoma (GBM). More importantly, it is found that H2 can suppress the stemness of gliomas stem cells, curbing both proliferation and infiltration of GBM. Furthermore, since pCNMC@Pt and light source is precisely co-localized through a self-built loading and illumination system, GBM in mouse brains can be efficiently treated, providing an alternative gas therapy approach to cure infiltrating tumors. This article is protected by copyright. All rights reserved.

Investigating AgCl-SnO2 nanocomposite for photocatalytic degradation of azo dye, associated reaction pathways, and its antibacterial activity

Herein, AgCl-SnO2 nanocomposite (NC) fabricated through a facile hydrothermal method exhibit substantial potential as an efficient and economical photocatalyst and bactericidal agent. The formation of spherical AgCl-SnO2 NC was confirmed through PXRD and SEM, with an average crystalline size of 12 nm. DR spectra and Kubelka-Munk function were used to determine the band gaps of AgCl (3.10 eV) and SnO2 (3.48 eV). The synthesized NC achieve successful photocatalytic degradation (98 %) of orange-G (OG) dye within 60 min. The NC’s potential was also elucidated by investigating the role of sacrificial reagents. Formation of •OH free radicals is confirmed from photoluminescence studies using terephthalic acid. The effective degradation of OG dye has been substantiated, resulting in the generation of numerous intermediate products with reduced toxicity, such as substituted phenols and aromatic dicarboxylic compounds. Furthermore, the NC demonstrated excellent efficiency even after six consecutive cycles, indicating its stability, regenerative property, and recyclability. The NC also exhibits significant antimicrobial activity against Escherichia coli.

Fabricating of multi-interfacial charge transfer paths in the novel noble-metal-free Ni2P/ZnS/g-C3N4 ternary nanocomposite for enhanced charge separation and transfer for photocatalytic H2 generation

This work reports the development of a novel Ni₂P/ZnS/C₃N₄ ternary nanocomposite photocatalyst for efficient hydrogen (H₂) production. The nanocomposite was synthesized using a facile approach combining hydrothermal synthesis, ball milling, and wet impregnation methods then characterized using various techniques. Photocatalytic H₂ generation was evaluated under simulated solar irradiation with sodium sulfite (Na₂SO₃)/sodium sulfide (Na₂S) as sacrificial reagents. The optimized 3NP/ZnS-8CN (3% Ni2P/ZnS/8% C3N4) catalyst displayed an exceptional H₂ generation rate of 3991 µmol h⁻¹ g⁻¹, exceeding both pristine g-C3N4 (by 10.2 times) and 3% Ni2P/ZnS (by 1.2 times). This represents the highest reported rate of H₂ evolution for a graphitic carbon nitride (g-C3N4) based ternary nanocomposite under simulated solar radiation. Furthermore, the 3NP/ZnS-8CN photocatalyst exhibited good stability over four reaction cycles. This study provides valuable insights for designing efficient noble metal-free g-C3N4-based photocatalysts, which can significantly contribute to the transition to solar-driven hydrogen generation. The results of this study suggest that the synthesized composite materials hold significant promise for the advancement of new energy technologies.

Photocatalytic Nitrogen Fixation Coupled with the Generation of Value-Added Chemicals from N2 and Cellulose over MoO3 Nanosheets.

Photocatalytic nitrogen fixation from N2 provides an alternative strategy for ammonia (NH3) production, but it was limited by the consumption of a sacrificial electron donor for the currently reported half-reaction system. Here, we use naturally abundant and renewable cellulose as the sacrificial reagent for photocatalytic nitrogen fixation over oxygen-vacancy-modified MoO3 nanosheets as the photocatalyst. In this smartly designed photocatalytic system, the photooxidation of cellulose not only generates value-added chemicals but also provides electrons for the N2 reduction reaction and results in the production of NH3 with a maximum rate of 68 μmol·h-1·g-1. Also, the oxygen vacancies provide efficient active sites for both cellulose oxygenolysis and nitrogen fixation reactions. This work represents useful inspiration for realizing nitrogen fixation coupled with the generation of value-added chemicals from N2 and cellulose through a photocatalysis strategy.

Visible-light harvesting SrTiO3 solid solutions for photocatalytic hydrogen evolution from water.

The fabrication of solid solutions represents a compelling approach to modulating the physicochemical properties of materials. In this study, we achieved the successful synthesis of solid solutions comprising SrTiO3 and SrTaO2N (denoted as (SrTiO3)1-x-(SrTaO2N)x, 0 ≤ x ≤ 1) using the magnesium powder-assisted nitridation method. The absorption edge of (SrTiO3)1-x-(SrTaO2N)x is tunable from 500 to 600 nm. The conduction band minimum (CBM) of (SrTiO3)1-x-(SrTaO2N)x comprises the Ti 3d orbitals and the Ta 5d orbitals, while the valence band maximum (VBM) consists of the O 2p and N 2p orbitals. The microstructure of the (SrTiO3)1-x‑(SrTaO2N)x consists of small nanoparticles, exhibiting a larger specific surface area than the parent compounds of SrTiO3 and SrTaO2N. In the photocatalytic hydrogen evolution reaction (HER) with sacrificial reagents, the activity of solid solutions is notably superior to that of nitrogen-doped SrTiO3 and SrTaO2N. This superiority is mainly attributed to its broad light absorption range and high charge separation efficiency, which indicates its potential as a promising photocatalytic material. Moreover, the magnesium powder-assisted nitridation method exhibits obvious advantages for the synthesis of oxynitrides and bears instructional significance for the synthesis of other nitrogen-containing compounds and even sulfur-containing compounds.

Regulation of d-band center of TiO2 through fluoride doping for enhancing photocatalytic H2O2 production activity

Titanium dioxide (TiO2) has received extensive attention for photocatalytic hydrogen peroxide (H2O2) production, with the d-band center related to the adsorption performance, which affects the photocatalytic reaction process. Herein, an ingenious strategy to lower the antibonding-orbital occupancy in the Ti 3d orbital by fluoride ion (F−) doping is proposed, with density functional theory calculations predicting that F-doping into TiO2 induces a non-uniform charge distribution and enables an upshift of the d-band center in F/TiO2. This manipulation provides accessible active centers with favorable d-band energy levels, which can improve the charge-transfer behavior, strengthen the interaction between the adsorbed oxygen and the photocatalyst, and reduce the adsorption energy of oxygen, eventually promoting the photocatalytic H2O2 production rate. The experimental results further confirm that a lower antibonding-orbital occupancy can intensify the adsorption of atomic oxygen at the Ti sites. Electron paramagnetic resonance experiment reveals that the presence of F− ions in the lattice induces the formation of Ti3+ centers that localize the extra electron needed for charge compensation. Femtosecond transient absorption (fs-TA) spectroscopy suggests that photogenerated electrons are transferred from the conduction band of F/TiO2 to the Ti3+ surface states and surface F− ions, expediting the separation of electrons and holes. Consequently, with F− doping in TiO2, the photocatalytic H2O2 production yields improved from 277 to 467 μmol·g−1·h−1, with ethanol as a sacrificial reagent. This study provides a new strategy for regulating the d-band center to optimize the adsorption strength between the photocatalyst and oxygen atoms and achieve enhanced photocatalytic H2O2 production performance.

Photocatalytic Dinitrogen Reduction to Ammonia over Biomimetic FeMoSx Nanosheets.

Reduction of atmospheric dinitrogen (N2) to ammonia (NH3) using water and sunlight in the absence of sacrificial reducing reagents at room temperature is very challenging and is considered an eco-friendly approach to meet the rapidly increasing demand for nitrogen storage, fertilizers, and a sustainable society. Currently, ammonia production via the energy-intensive Haber-Bosch process causes ∼350 million tons of carbon dioxide (CO2) emission per year. Interestingly, natural N2 fixation by the nitrogenase enzyme occurs under ambient conditions. Unfortunately, N2 fixation on biomimetic catalysts has rarely been studied. To mimic biological nitrogen fixation, herein, we synthesized the novel iron molybdenum sulfide (FeMoSx) micro-/nanosheets via a simple hydrothermal approach for the first time. Further, we successfully demonstrated the photochemical conversion of N2 to NH3 over a biomimetic FeMoSx photocatalyst. The estimated yield is around 99.79 ± 6.0 μmol/h/g photocatalyst with a quantum efficiency of ∼0.028% at 532 nm visible-light wavelength. Besides, we also systematically studied the influence of key factors to further improve NH3 yields. Overall, this study paves a new pathway to fabricate carbon-free, photochemical N2 fixation materials for future applications.

Construction of an Electron Capture and Transfer Center for Highly Efficient and Selective Solar-Light-Driven CO2 Conversion.

Exploring high-efficiency photocatalysts for selective CO2 reduction is still challenging because of the limited charge separation and surface reactions. In this study, a noble-metal-free metallic VSe2 nanosheet was incorporated on g-C3N4 to serve as an electron capture and transfer center, activating surface active sites for highly efficient and selective CO2 photoreduction. Quasi in situ X-ray photoelectron spectroscopy (XPS), soft X-ray absorption spectroscopy (sXAS), and femtosecond transient absorption spectroscopy (fs-TAS) unveiled that VSe2 could capture electrons, which are further transferred to the surface for activating active sites. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations revealed a kinetically feasible process for the formation of a key intermediate and confirmed the favorable production of CO on the VSe2/PCN (protonated C3N4) photocatalyst. As an outcome, the optimized VSe2/PCN composite achieved 97% selectivity for solar-light-driven CO2 conversion to CO with a high rate of 16.3 μmol·g-1·h-1, without any sacrificial reagent or photosensitizer. This work offers new insights into the photocatalyst design toward highly efficient and selective CO2 conversion.

Active Sites Formed on InVO4/Co3O4 S‐Scheme Heterostructure for Photocatalytic Hydrogen Production

AbstractThe reasonable design of S‐scheme heterojunction to avoid unwanted charge transfer paths in hybrid semiconductors is considered to be an attractive method to obtain efficient photocatalytic hydrogen evolution activity. The photocatalytic hydrogen evolution performance of the system was improved by loading ultra‐thin InVO4 nanosheets on the surface of hollow cube Co3O4 to form an S‐scheme heterojunction. Benefiting from the unique nano‐cage structure derived from the zeolitic imidazolate frameworks (ZIF) series, it not only provides a good carrier for activating and stabilizing InVO4 nanosheets but also effectively avoids the masking of active sites caused by self‐agglomeration, which is more conducive to the exposure of more active sites. In the presence of sensitizer and sacrificial reagent, the optimized InVO4/Co3O4 has a more competitive H2 production, which is undoubtedly due to the construction of S‐scheme heterojunctions and unique spatial structure that facilitates the spatial separation of photoexcited charges. It is further confirmed that the photogenerated carrier transfer follows the S‐scheme mechanism by in‐situ irradiation XPS test.

Directed Electron Delivery from a Pb-Free Halide Perovskite to a Co(II) Molecular Catalyst Boosts CO2 Photoreduction Coupled with Water Oxidation.

The development of high-performance photocatalytic systems for CO2 reduction is appealing to address energy and environmental issues, while it is challenging to avoid using toxic metals and organic sacrificial reagents. We here immobilize a family of cobalt phthalocyanine catalysts on Pb-free halide perovskite Cs2AgBiBr6 nanosheets with delicate control on the anchors of the cobalt catalysts. Among them, the molecular hybrid photocatalyst assembled by carboxyl anchors achieves the optimal performance with an electron consumption rate of 300±13 μmol g-1 h-1 for visible-light-driven CO2-to-CO conversion coupled with water oxidation to O2, over 8 times of the unmodified Cs2AgBiBr6 (36±8 μmol g-1 h-1), also far surpassing the documented systems (<150 μmol g-1 h-1). Besides the improved intrinsic activity, electrochemical, computational, ex-/in situ X-ray photoelectron and X-ray absorption spectroscopic results indicate that the electrons photogenerated at the Bi atoms of Cs2AgBiBr6 can be directionally transferred to the cobalt catalyst via the carboxyl anchors which strongly bind to the Bi atoms, substantially facilitating the interfacial electron transfer kinetics and thereby the photocatalysis.

Directed Electron Delivery from a Pb‐Free Halide Perovskite to a Co(II) Molecular Catalyst Boosts CO2 Photoreduction Coupled with Water Oxidation

AbstractThe development of high‐performance photocatalytic systems for CO2 reduction is appealing to address energy and environmental issues, while it is challenging to avoid using toxic metals and organic sacrificial reagents. We here immobilize a family of cobalt phthalocyanine catalysts on Pb‐free halide perovskite Cs2AgBiBr6 nanosheets with delicate control on the anchors of the cobalt catalysts. Among them, the molecular hybrid photocatalyst assembled by carboxyl anchors achieves the optimal performance with an electron consumption rate of 300±13 μmol g−1 h−1 for visible‐light‐driven CO2‐to‐CO conversion coupled with water oxidation to O2, over 8 times of the unmodified Cs2AgBiBr6 (36±8 μmol g−1 h−1), also far surpassing the documented systems (&lt;150 μmol g−1 h−1). Besides the improved intrinsic activity, electrochemical, computational, ex‐/in situ X‐ray photoelectron and X‐ray absorption spectroscopic results indicate that the electrons photogenerated at the Bi atoms of Cs2AgBiBr6 can be directionally transferred to the cobalt catalyst via the carboxyl anchors which strongly bind to the Bi atoms, substantially facilitating the interfacial electron transfer kinetics and thereby the photocatalysis.