High-performance Photocatalysts Research Articles

Synthesis of carbon dots with tailored heteroatomic structure for achieving ultrahigh effectiveness in persulfate activation

Carbon dots (CDs) are normally feature with zero-dimensional structure, excellent solubility, good biosafety, and exceptional photoelectronic properties, thus, awakening the homogeneous-like photocatalytic potency of CDs in peroxymonosulfate (PMS) activation can afford new idea for water body remediation. Herein, we presented a facile nitrogen and sulfur co-doping strategy for the development of high-performance CDs-based photocatalysts. Through the deep investigation on the structure-activity relationship, we proposed that the incorporated pyridinic N within CDs structure could serve as efficient Lewis basic sites for PMS confinement. Importantly, the co-existence of oxidized sulfur groups and specific nitrogen speciation (pyridine N and pyrrolic N) induced unique “push-pull” effect on the photogenerated carriers within the surface state of S,N co-doped CDs. The unique synergy sites and surface hydrophilic nature conferred the CDs exceptional photocatalytic effectiveness, presenting a remarkable PMS consumption ratio of 7.62 per gram of the CDs photocatalyst within just 20 min. Profited from the improved kinetics of interfacial reactions, the CDs-photocatalyzed oxidation system that consisted largely of sulfate radicals can completely degrade rhodamine B within 12.5 min, and hold great potential in long-term operation without needing to regenerate CDs catalyst.

Ultrathin Porous Carbon Nitride Anchored with Pt Nanoclusters for Synergistic Enhancement of Hydrogen Production in Alkaline Photocatalytic Polyester Reforming.

Photocatalytic reforming (PR) of polyester waste, fueled by renewable sources like solar energy, offers a sustainable method for producing clean H2 and valuable by-products under mild conditions. The design of high-performance photocatalyst plays a pivotal role in determining the efficacy of an alkaline polyester PR system, influencing H2 generation activity and selectivity. Here, ultrathin porous carbon nitride nanosheets (UP-CN) loaded with Pt nanoclusters (Pt NCs, average diameter of 1.7nm) with uniform Pt NCs distribution are introduced. The resulting Pt NCs/UP-CN catalyst can accelerate charge and mass transfer while providing additional active sites, achieving superior H2 generation rates of 11.69mmol gcat -1 h-1 and 2923mmol gPt -1 h-1 under AM 1.5 light, which nine times higher than that of Pt nanoparticles-bulk graphitic carbon nitride composite (1.29mmol gcat -1 h-1 and 258mmol gPt -1 h-1) as counterpart. This performance also surpasses that of previously reported carbon nitride-based and TiO2-based photocatalysts. Moreover, the density functional theory calculations reveal a significant reduction in the energy barrier for the water dissociation step (H2O + * → *H + OH) at the interface between UP-CN and anchored Pt NCs, showcasing the synergistic effect between Pt NCs and UP-CN. This catalytic system also exhibits universality across various polyester plastics.

Interfacial contact-driven enhanced environmental photocatalysis of CdS-loaded OH-functionalized carbon nanotubes with low biotoxicity

CdS is a promising visible-light-driven photocatalyst, but it is highly toxic. Therefore, exploring alternatives that minimize toxicity while maintaining its photocatalytic properties is crucial. Carbon allotropes have been suggested as eco-friendly scaffolds for making high-performance photocatalysts with a small amount of toxic but visible light-responsive CdS additive to reduce environmental risk. However, it is unclear how small amounts of CdS in the nanocomposite can avoid a threat to environmental safety, and the role of surface functional groups on the physical interfaces for photocatalysis has not been sufficiently elucidated. Here, we used OH-functionalized carbon nanotubes (CNT-OH) as a support for CdS nanoparticles (NPs) and investigated the effect of CdS loading on photocatalytic activity and toxicity. Comprehensive microscopy coupled with machine learning-assisted spectroscopy revealed that electronic structure alterations occur uniquely at heterojunctions where CdS NPs contact CNT-OH, uncovering them as being catalytically active. Notably, the CNT-OH loaded by only 3 wt% CdS NPs resulted in a highly enhanced photocatalytic activity comparable to pure CdS NPs for selective oxidation of 2,5-hydroxymethylfurfural and degradation of 4-chlorophenol. These findings provide insight into heterocontact engineering using visible light-responsive catalysts and functionalized platforms to develop environmentally benign photocatalysts with high performance.

Synthesis of Carbon Nitride Polymorphs by Sacrificial Template Method: Correlation between Physicochemical Properties and Photocatalytic Performance.

Carbon nitride compounds (CNCs) in the form of graphitic carbon nitride (g-C3N4) and poly(heptazine imide) were synthesized using different metal chloride salts (MClx), i.e., NaCl, KCl and CaCl2, as sacrificial templates and by varying the MClx to melamine molar ratios. A systematic study of their photocatalytic activity for H2 production in relation to the physicochemical, morphological, and optical properties was carried out. Each sample was tested achieving the highest hydrogen evolution rates of about 7660 µmol g-1 h-1, 5380 µmol g-1 h-1 and 3140 µmol g-1 h-1 using CaCl2, KCl, and NaCl, respectively. This work demonstrates how the synthesis of CNCs with different MClx leads to the production of high-performance photocatalysts due to a combination of factors as the formation of vacancies or cyano groups, a shift in the optical threshold and tuning of micro(nano)structure. The results demonstrate that, when CaCl2 is used as a sacrificial template, porous and exfoliated g-C3N4 nanosheets are formed leading to hydrogen productions which outperform most of the previously reported g-C3N4 prepared using a single synthetic step.

Boron-Doped Cu3Ni/BaTi4O9 Porous Composite by Regulating the Electronic Structure as High-Performance Photocatalysts for the H2 Evolution Reaction

Boron-Doped Cu₃Ni/BaTi₄O₉ Porous Composite by Regulating the Electronic Structure as High-Performance Photocatalysts for the H₂ Evolution Reaction

Nanoporous Heterojunction Photocatalysts with Engineered Interfacial Sites for Efficient Photocatalytic Nitrogen Fixation.

Photocatalytic N2 reduction reaction (PNRR) offers a promising strategy for sustainable production of ammonia (NH3). However, the reported photocatalysts suffer from low efficiency with great room to improve regarding the charge carrier utilization and active site engineering. Herein, a porous and chemically bonded heterojunction photocatalyst is developed for efficient PNRR to NH3 production via hybridization of two semiconducting metal-organic frameworks (MOFs), MIL-125-NH2 (MIL=Material Institute Lavoisier) and Co-HHTP (HHTP=2,3,6,7,10,11-hexahydroxytripehenylene). Experimental and theoretical results demonstrate the formation of Ti-O-Co chemical bonds at the interface, which not only serve as atomic pathway for S-scheme charge transfer, but also provide electron-deficient Co centers for improving N2 chemisorption/activation capability and restricting competitive hydrogen evolution. Moreover, the nanoporous structure allows the transportation of reactants to the interfacial active sites at heterojunction, enabling the efficient utilization of charge carriers. Consequently, the rationally designed MOF-based heterojunction exhibits remarkable PNRR performance with an NH3 production rate of 2.1 mmol g-1 h-1, an apparent quantum yield (AQY) value of 16.2% at 365 nm and a solar-to-chemical conversion (SCC) efficiency of 0.28%, superior to most reported PNRR photocatalysts. Our work provides new insights into the design principles of high-performance photocatalysts.

Dual-pathway charge transfer mechanism of anatase/rutile TiO2-Ag3PO4 hollow photocatalyst promotes efficient degradation of pesticides

Exploring high-performance photocatalysts still remains a big challenge due to poor charge separation efficiency. Herein, we prepare a novel anatase/rutile TiO2-Ag3PO4 hollow photocatalyst (A/R-TiO2-Ag3PO4) for addressing this challenge. Microstructural characterization and photoelectric measurements confirm that the synergy of hollow structure and dual-heterojunction can provide abundant active sites and boost efficient charge separation through dual-pathway charge transfer mechanism. The A/R-TiO2-Ag3PO4 photocatalyst exhibits the highest photocurrent density (15.25 µA cm−2), which is 8.4 and 5.2 times than that of A-TiO2-Ag3PO4 (1.82 µA cm−2) and P25-Ag3PO4 (2.93 µA cm−2), respectively. Photo-degradation experiment shows that A/R-TiO2-Ag3PO4 presents a high degradation percentage (98.7 %) of thiamethoxam (THX) within 30 min, which is 1.45 and 1.23 times than that of A-TiO2-Ag3PO4 (68.1 %) and P25-Ag3PO4 (80.7 %), respectively. Furthermore, the degradation percentage of THX by A/R-TiO2-Ag3PO4 is as high as 96.4 % after seven successive cycles, indicating excellent cycling stability. Therefore, this work provides a new insight into exploring other high-performance photocatalysts by combining hollow structure and dual-heterojunction.

Green Synthesis of carbon quantum dots for enhancing photocatalytic activity: Hydrogen/oxygen evolution and dye photodegradation

Carbon quantum dots (CQDs) have recently attracted attention across various fields due to their small size, high conductivity, fluorescence emission, low toxicity, and other desirable characteristics. In this study, highly fluorescent CQDs with an average diameter of 3.7 nm were prepared via microwave irradiation using a standard commercial microwave oven and glycerol as solvent. Several cation promoters were examined for CQD synthesis, with copper ions ultimately chosen for comprehensive characterization and application. The CQDs were impregnated onto both commercially available and microwave-synthesized TiO2 nanoparticles. The photocatalytic activity was evaluated with respect to the hydrogen and oxygen generation. Under the employed conditions, the oxygen evolution reaction (OER) exhibited over 12 times higher efficiency than the hydrogen evolution reaction (HER). The enhanced OER activity is attributed to the high electronic conductivity of the small Cu doped CQDs@TiO2 (Cu-CQDs@TiO2) facilitating an efficient electron transfer for the OER . Visible light activity (λ ≥ 400 nm) was demonstrated by photodegradation of the indigo carmine (IC) solution used as a model pollutant. Irradiation in the presence of the Cu-CQDs@TiO2 photocatalyst resulted in complete degradation of the dye in less than 3 hours. The results presented here provide a promising methodology for designing high-performance photocatalysts based on environmentally friendly CQD syntheses. Crucial applications, from renewable energy production to environmental remediation, will benefit from strategies using the carbon abundance on Earth.

MoS2-CdS composite for photocatalytic reduction of hexavalent chromium and thin film optoelectronic device applications

We introduce an enhanced light-harvesting MoS2-based nanocomposite exhibiting improved solar light induced photocurrent generation, both in solution and solid phases. The MoS2-CdS composite was synthesized via easy to achieve, cost effective, two-step solution process for the photocatalytic potassium dichromate [Cr(VI)] reduction and photocurrent generation in thin-film optoelectronic devices. Incorporating 10 wt% MoS2 into the composite increased the degradation efficiency of CdS from 43.9 to 91.9%. Furthermore, the MoS2-CdS composite demonstrated a 2.88-fold increase in the degradation rate constant and a 2.15% enhancement in the apparent quantum yield compared to controlled CdS. Additionally, the electrical power consumption per order decrease in Cr(VI) reduced from 25.74 kWh m−3 for controlled CdS to 9 kWh m−3 aimed at 10 wt% MoS2-CdS composite, indicating optimal synergy between the counterparts of MoS2-CdS in its composite. The resulting thin-film device with 10 wt% MoS2-CdS exhibited robust photocurrent generation and nonlinear I–V characteristics under solar illumination, attributed to the unique electronic properties of the MoS2-CdS heterojunction, influencing carrier transport via band alignment and interface carrier trapping effects. Moreover, photocurrent generation increased linearly with illumination intensity, and dynamic photo response studies revealed rapid photocurrent generation under illumination. Furthermore, the optoelectronic key parameters of CdS, including photosensitivity, photoresponsivity, and detectivity, were enhanced by factors of 5.09, 3.33, and 12.3, respectively, upon composite formation with MoS2. This study offers novel insights into developing high-performance and cost-effective bimetallic sulfide photocatalysts for efficient solar light-induced photocurrent generation in both solution and solid phases.

Synergistic Modulation of π-π* and n-π* Transitions by In Situ Phenol-Like Structure Integration for Efficiently Wide-Spectrum Hydrogen Production of Ultrathin Carbon Nitride.

2D carbon nitride nanosheets, exemplified by g-C3N4, offers significant structural benefits and enhanced photocatalytic activity. Nonetheless, the quantum confinement effect prevalent in nanoscale photocatalysts would result in an enlarged bandgap, potentially restricting the spectral absorption range and impeding improvements in photocatalytic efficiency. Here, a high-performance 2D photocatalyst with an extended spectral response is achieved by incorporating a novel phenol-like structure into the conjugated framework of ultrathin g-C3N4 nanosheet. This novel strategy features targeted pyrimidine doping to create a conjugated carbon zone in heptazine structure, offering a thermodynamically favorable pathway for hydroxyl functionalization during the annealing exfoliation process. Consequently, the π-π* transition energy in the material is significantly decreased, and the active lone pair electrons in phenol-like structure induces a new n-π* transition with notably enhanced absorption from 500 to 650nm. The optimized material shows a dramatic enhancement in photocatalytic activity, achieving ≈72 times than the activity of bulk g-C3N4, and demonstrating a measurable H2 production rate of 6.57µmol g-1 h-1 under 650nm light. This study represents a significant step forward in the strategic design of 2D photocatalysts, with tailored electronic structures that significantly boost light absorption and photocatalytic efficiency.

Shaping and Doping Metal-Organic Framework-Derived TiO2 to Steer the Selectivity of Photocatalytic CO2 Reduction toward CH4.

Steering selectivity in photocatalytic conversion of CO2, especially toward deep reduction products, is vital to energy and environmental goals yet remains a great challenge. In this work, we demonstrate a facet-dependent photocatalytic selective reduction of CO2 to CH4 in Cu-doped TiO2 catalysts exposed with different facets synthesized by a topological transformation from MIL-125 (Ti) precursors. The optimized round cake-like Cu/TiO2 photocatalyst mainly exposed with the (001) facet exhibited a high photocatalytic CO2 reduction performance with a CH4 yield of 40.36 μmol g-1 h-1 with a selectivity of 94.1%, which are significantly higher than those of TiO2 (001) (4.70 μmol g-1 h-1 and 52.6%, respectively), Cu/TiO2 (001 + 101) (18.95 μmol g-1 h-1 and 69.6%, respectively), and Cu/TiO2 (101) (14.73 μmol g-1 h-1 and 78.9%, respectively). The results of experimental and theoretical calculations demonstrate that the Cu doping dominating the promoted separation and migration efficiencies of photogenerated charges and the preferential adsorption on (001) facets synergistically contribute to the selective reduction of CO2 to CH4. This work highlights the significance of synergy between facet engineering and ion doping in the design of high-performance photocatalysts with respect to selective reduction of CO2 to multielectron products.

Synergy of sulfur vacancy and piezoelectric effect to tune charge migration in Sv-ZnIn2S4/UiO-66-NH2 for efficient photocatalytic H2 evolution

High-performance photocatalytic H2 evolution materials require strong light absorption capability, excellent photogenerated charge separation ability and efficient charge carrier migration capability. In this study, we designed a piezoelectric photocatalytic heterojunction composed of UiO-66-NH2 and ZnIn2S4 nanosheets with sulfur vacancies. The Sv-UZ-45 heterojunction achieved piezoelectric photocatalytic H2 evolution performance of 3886.4 μmol·g-1·h-1, with a 4.6 times enhancement due to the synergistic effect of piezoelectric effect and defect engineering. The introduction of sulfur vacancies enables the heterojunction to obtain stronger light absorption, while the higher CB position of rich-sulfur vacancies ZnIn2S4 is more favorable for the photocatalytic reduction reaction. In addition, the heterojunction with rich-sulfur vacancies exhibits a stronger piezoelectric effect than without vacancies, thus providing a powerful driving force for the separation of photogenerated charge carriers. Finally, ESR was used to explain the potential photocatalytic mechanism and showed that Sv-UZ-45 adheres to the Z-scheme carrier migration pathway. This work elucidates the synergistic interaction between piezoelectric effect and defect engineering, providing new insights for the further development of high-performance piezoelectric photocatalysts.

S-scheme carbon doped-TiO2/ZnIn2S4 heterojunction for enhanced photocatalytic degradation of microcystin-LR and hydrogen evolution

Photocatalytic degradation of pollutants coupled with hydrogen (H2) evolution has emerged as a promising solution for environmental and energy crises. However, the fast recombination of photoexcited electrons and holes limits photocatalytic activities. Herein, an S-scheme heterojunction carbon doped-TiO2/ZnIn2S4 (C–TiO2/ZnIn2S4) was designed by substituting oxygen sites within C–TiO2 by ZnIn2S4. Under visible light irradiation, the optimal C–TiO2/ZnIn2S4 exhibits a higher degradation efficiency (88.6%) of microcystin-LR (MC-LR), compared to pristine C–TiO2 (72.9%) and ZnIn2S4 (66.8%). Furthermore, the H2 yield of the C–TiO2/ZnIn2S4 reaches 1526.9 μmol g−1 h−1, which is 3.83 times and 2.87 times that of the C–TiO2 and ZnIn2S4, respectively. Experimental and theoretical investigations reveal that an internal electric field (IEF) informed in the C–TiO2/ZnIn2S4 heterojunction, accelerates the separation of photogenerated charge pairs, thereby enhancing photocatalytic efficiency of MC-LR degradation and H2 production. This work highlights a new perspective on the development of high-performance photocatalysts for wastewater treatment and H2 generation.

Synergistic enhancement of singlet oxygen generation in Au and oxygen vacancy co-modified Bi2MoO6 ultrathin nanosheets for efficient ciprofloxacin degradation

Solar-driven molecular oxygen activation (MOA) is crucial for generating reactive oxygen species (ROS) for pollutant degradation, while the low activation efficiency greatly weakens the degradation efficiency. Herein, oxygen vacancies (OVs) and Au nanoparticles are co-introduced into Bi2MoO6 (ABMOH) to enhance the photocatalytic activity of Bi2MoO6 (BMO), thereby promoting MOA efficiency. Density functional theory demonstrates that the introduction of OVs not only improves the molecular oxygen adsorption on BMO, and but also strengthens the O-O bond dissociation of molecular oxygen, which is beneficial to MOA. Meanwhile, the unique localized surface plasmon resonance effect of Au nanoparticles immensely increases the photo-absorption capacity. Crucially, both OVs and Au nanoparticles work as “electron traps” to capture photogenerated electrons, thereby accelerating charge transfer. Based on the advantage of OVs and Au nanoparticles, ABMOH displays excellent MOA efficiency, and the degradation rate constant of ciprofloxacin (CIPF) by ABMOH-4 is 3.62-fold higher than BMO. Free radical trapping experiment and electron spin resonance suggest that singlet oxygen (1O2) can be selectively formed in the ABMOH system for CIPF degradation, and superoxide radical (•O2–) conversion and energy transfer are two pathways for 1O2 formation. This investigation serves as a beacon for the strategic design of high-performance and stable photocatalysts for MOA activation, paving the way for advancements in environmental remediation.

Sulfur vacancies form charge transport channels on the S-type heterojunction engineered interface to enhance photocatalytic performance

This article presents the synthesis of an S-type heterojunction photocatalyst through a straightforward hydrothermal process, which involves the combination of FeWO4 with Zn0.5Cd0.5S containing sulfur vacancies (Zn0.5Cd0.5Ssv). The study delves into the intrinsic role of sulfur vacancies in enhancing the photocatalytic performance of the S-type heterojunction. The creation of sulfur vacancies effectively controls charge separation and triggers a rapid charge transfer pathway at the heterojunction, improving light absorption and permitting the formation of more photoinduced charges. The material demonstrates an impressive degradation efficiency, capable of breaking down 79.38% of IOH within just 40 minutes. It exhibits robust catalytic activity under both mildly acidic and mildly basic conditions, showing notable resistance to various anions and cations present in water, as well as a significant tolerance to high concentrations of humic acid. Further, trapping experiments reveal that hydroxyl radicals (•OH) and superoxide radicals (•O2⁻) are the predominant reactive species driving the photocatalytic process. This research sheds new light on the modulation of photogenerated charge carrier dynamics at the heterointerface, offering valuable guidance for the development of high-performance S-type photocatalysts.

Ferrocene-based 2D metal–organic framework nanosheet for highly efficient photocatalytic seawater uranium recovery

Sustainable uranium supply is critical for the long-term development of nuclear energy. The photocatalytic reduction of soluble hexavalent uranium to insoluble tetravalent uranium using photocatalysts has been recognized as a highly promising method for uranium recovery. However, existing photocatalysts face limitations such as restricted visible-light absorption and poor charge transfer capability, which hinder their photocatalytic uranium recovery performance. In this work, 1,1′-ferrocene dicarboxylic acid (FcDA) was introduced to synthesize the photocatalyst Zr-Fc-MOF3. The incorporation of FcDA broadened the visible light absorption range and reduced the band gap of Zr-Fc-MOF3, thereby enhancing electron-hole pair separation and carrier transport efficiencies. Moreover, the two-dimensional (2D) nanosheet structure of Zr-Fc-MOF3 provided a large surface area, allowing full exposure of active sites. Additionally, Fe(II) in FcDA generated photoelectrons upon light excitation to facilitate uranium reduction, and the recyclable redox behavior of Fe(II) conferred high reusability of the photocatalyst. Consequently, Zr-Fc-MOF3 demonstrated a high photocatalytic uranium recovery capacity of 8.29 mg g−1 over 10 days in nature seawater (NSW), with a uranium recovery rate of 0.829 mg g−1 d−1, surpassing most other photocatalysts applied in NSW. These findings suggest that designing 2D nanosheet materials with ligands capable of efficient photoelectron generation is a promising approach for developing high-performance uranium recovery photocatalysts.

Hybrid NiCo2O4-BiOCOOH heterostructure nanocomposite impregnated porous polymer monolith as high-performance visible light photocatalyst for the decontamination of antimicrobial pollutants

We report a first-of-its-kind preparation of a NiCo2O4-BiOCOOH heterostructure as visible light-responsive nanocomposites (NCs) for the fast decontamination of moxifloxacin drug molecules, with longer persistence and non-biodegradability nature that could promote gene-resistance bacteria in aqueous medium. Further, a reusable/recoverable photocatalyst is fabricated through the uniform decoration of NiCo2O4(15 %)-BiOCOOH(85 %), i.e., NB-15 NCs across a tailor-made poly(EGDMA) monolith (PEM) that serves as the host template for the photoactive NCs. The electron microscopy, optical spectroscopy, diffraction, and surface analysis techniques confirm the photocatalyst's superior structural morphology, surface topography, and porosity features that assist in high-performance photocatalysis. The inorganic-organic hybrid photocatalyst exhibits a narrow energy bandgap that promotes ample generation of reactive oxygen species upon visible light irradiation, as confirmed by the electrochemical and spectroscopic analysis. The BET/BJH plot for the photocatalyst reveals a large surface area of 345 m2/g, with voluminous pore distributions (2–80 nm), indicating the coexistence of mesopores-infused macroporous framework that offers better contact/equilibration of the pollutant molecules with the abundantly dispersed photoactive sites. The optimized parameters reveal ≥99.2 % drug dissipation in ≤0.33 h and drug mineralization in ≤2.0 h, using a mere 50 mg of photocatalyst irradiated with a 150 W/cm2 tungsten lamp. The synthesized photocatalyst has a simple/cost-saving procedure that can transform into scalable, cheaper, and eco-friendly products for the real-time monitoring of toxic pollutants. Besides, the photocatalyst exhibits excellent stability and reusability characteristics for efficiently decontaminating organic pollutants, thus highlighting an innovative approach for fabricating high-performance photocatalysts.

Heteropoly blue-modified ultrathin bismuth oxychloride nanosheets with oxygen vacancies for efficient photocatalytic nitrogen fixation in pure water

Photocatalytic nitrogen reduction is a promising green technology for ammonia synthesis under mild conditions. However, the poor charge transfer efficiency and weak N2 adsorption/activation capability severely hamper the ammonia production efficiency. In this work, heteropoly blue (r-PW12) nanoparticles are loaded on the surface of ultrathin bismuth oxychloride nanosheets with oxygen vacancies (BiOCl-OVs) by electrostatic self-assembly method, and a series of xr-PW12/BiOCl-OVs heterojunction composites have been prepared. Acting as a robust support, ultrathin two-dimensional (2D) structure of BiOCl-OVs inhibits the aggregation of r-PW12 nanoparticles, enhancing the interfacial contact between r-PW12 and BiOCl. More importantly, the existence of oxygen vacancies (OVs) provides abundant active sites for efficient N2 adsorption and activation. In combination of the enhanced light absorption and promoted photogenerated carriers separation of xr-PW12/BiOCl-OVs heterojunction, under simulated solar light, the optimal 7r-PW12/BiOCl-OVs exhibits an excellent photocatalytic N2 fixation rate of 33.53 µmol g-1h−1 in pure water, without the need of sacrificial agents and co-catalysts. The reaction dynamics is also monitored by in situ FT-IR spectroscopy, and an associative distal pathway is identified. Our study demonstrates that construction of heteropoly blues-based heterojunction is a promising strategy for developing high-performance N2 reduction photocatalysts. It is anticipated that combining of different defects with heteropoly blues of different structures might provide more possibilities for designing highly efficient photocatalysis systems.

Bi4Ti3O12/Bi4O5I2/Bi12TiO20 double Z-scheme heterojunction: Efficient purification of water pollutants by multi-channel charge transfer

The construction of double Z-scheme heterojunctions has significant merits in facilitating photogenerated charge migration and realizing efficient redox reduction. In this work, a dual Z-scheme heterojunction Bi4Ti3O12/Bi4O5I2/Bi12TiO20 (BT/BOI/BTO) with abundant oxygen vacancies is constructed to achieve multi-channel rapid charge transfer. The transport modes of the charges at the interface of the double Z-scheme of BT/BOI/BTO are investigated through detailed analysis of the Fermi energy levels, energy band structures, and electron spin resonance spectra. Dual Z-scheme heterojunction generates a dual-interface electric field on Bi4Ti3O12 nanosheets. Carriers are driven to migrate directionally along multiple channels. Effective activation of oxygen molecules by oxygen vacancies in BT/BOI/BTO. BT/BOI/BTO achieved 100 % removal of tetracycline hydrochloride (TCH) compared to the original material. The detailed degradation pathways of TCH were elucidated by liquid chromatography-mass spectrometry (LC-MS) analysis. This work presents a new insight into the construction of high-performance Z-scheme photocatalysts with multichannel charge transfer properties.

Confinement Synthesis of Atomic Copper-Anchored Polymeric Carbon Nitride in Crystalline UiO-66-NH2 for High-Performance CO2-to-CH3OH Photocatalysis.

Photocatalytic CO2 reduction to value-added fuels displays an attractive scenario to enhance energy supply and reduce global warming. We report herein the confinement synthesis of polymeric carbon nitride (PCN) incorporating with Cu single atoms (CuSAs) inside the crystalline UiO-66-NH2, which combines the merits of heterojunction photocatalysis and single-atom catalysis (SAC) to achieve high-performance CO2-to-CH3OH conversion. A series of spectral studies displays the formation of CuSAs@PCN inside the crystalline UiO-66-NH2. Remarkably, the ternary composite shows an excellent photocatalytic turnover frequency of 4.15 mmol·h-1·g-1 for CO2-to-CH3OH conversion. Theoretical and experimental studies demonstrate the doping of CuSAs, as well as the formation of type-II heterojunction, are causal factors to achieve CH3OH generation. The study provides new insights designing high-performance photocatalyst for CO2 conversion to fuels at atomic scale.