Interfacial Charge Research Articles

Building Asymmetric Zn-N3 Bridge between 2D Photocatalyst and Co-catalyst for Directed Charge Transfer toward Efficient H2O2 Synthesis.

Two-dimensional (2D) polymeric semiconductors are a class of promising photocatalysts; however, it remains challenging to facilitate their interlayer charge transfer for suppressed in-plane charge recombination and thus improved quantum efficiency. Although some strategies, such as π-π stacking and van der Waals interaction, have been developed so far, directed interlayer charge transfer still cannot be achieved. Herein, we report a strategy of forming asymmetric Zn-N3 units that can bridge nitrogen (N)-doped carbon layers with polymeric carbon nitride nanosheets (C3N4-Zn-N(C)) to address this challenge. The symmetry-breaking Zn-N3 moiety, which has an asymmetric local charge distribution, enables directed interfacial charge transfer between the C3N4 photocatalyst and the N-doped carbon co-catalyst. As evidenced by femtosecond transient absorption spectroscopy, charge separation can be significantly enhanced by the interfacial asymmetric Zn-N3 bonding bridges. As a result, the designed C3N4-Zn-N(C) catalyst exhibits dramatically enhanced H2O2 photosynthesis activity, outperforming most of the reported C3N4-based catalysts. This work highlights the importance of tailoring interfacial chemical bonding channels in polymeric photocatalysts at the molecular level to achieve effective spatial charge separation.

Needle growth of Nb2O5 nanoparticles on BiOCl nanosheets to fabricate S-scheme heterojunction with oxygen vacancies for enhanced photooxidation of cyclohexane

The exploration of cost-efficient, environmentally friendly, and high-efficacy photocatalysts for the enhanced selective photooxidation of cyclohexane to KA oil (cyclohexanone (CHA-one) and cyclohexanol (CHA-ol)) is a pivotal challenge in the industrial realm. Herein, the present study focuses on the synthesis of needle-like S-scheme heterojunction photocatalysts with oxygen vacancies, which are achieved by the needle growth integration of nano-sized Nb2O5 particles onto the BiOCl nanosheets. Remarkably, the 40 % Nb2O5/BiOCl composites exhibited superior performance in the solvent-free photooxidation of cyclohexane at room-temperature and under atmospheric pressure. The production yield of KA oil was 180.3 μmol (CHA-one/CHA-ol molar ratio = 3.5), and exceptional selectivity towards KA oil, reaching up to 99.3 %. The enhanced photocatalytic efficiency in cyclohexane oxidation can be attributed to the unique S-scheme heterogeneous interfaces with specific nanoneedle morphology, which result in the enhanced photonic absorption, effective charge carrier separation, a high density of oxygen vacancies, and the exposure of the highly reactive (001) plane of BiOCl. The excellent interfacial charge separation and transfer pathways of S-scheme heterojunction are disclosed by the in-depth EPR analysis and DFT calculations. These insights highlight the significant potential of the needle-like Bi-based S-scheme heterojunction photocatalysts for the efficient photooxidation of saturated alkanes.

Peeling-induced interfacial roughness and charging for enhanced triboelectric power generation

To date, there have been a lot of efforts to enhance the conversion efficiency of triboelectric nanogenerators (TENGs) via physical and chemical modifications of the polymer surface. Herein, we report that a facile peeling of polymer from a substrate can enhance the triboelectric power output. The peeling of spin-coated polydimethylsiloxane (PDMS) from glass and polytetrafluoroethylene (PTFE) substrates has revealed a considerable increase in interfacial roughness and lateral friction. Surface-sensitive X-ray photoemission spectroscopy and non-contact current measurements have also revealed the transfer of counter-material and interfacial charging. The surface roughness of peeled PDMS is significant for the PTFE substrate, while the surface charge is significant for the glass substrate. The triboelectric output power density for peeled PDMS from the substrate is similar, 10.3 µW/cm2, but significantly larger than that for as-grown PDMS (2.2 µW/cm2). The peeling strength of PDMS significantly increases for glass compared to PTFE after the oxygen plasma treatment of substrates. The triboelectric charge of peeled PDMS from a plasma-treated glass substrate is almost 1.3 times larger than that from a PTFE substrate. This work implies that peeling polymer from a rough substrate with a large adhesion force would be a facile and effective way to increase the triboelectric power output, without any delicate surface treatments.

Dual-defect AgBiO3/DCN S-scheme heterojunction for booted photocatalytic removal of Norfloxacin: Interfacial charge transfer, mechanism and toxicity assessment insights

Antibiotics pollution may pose a great risk to ecosystem and human health. In this work, an innovative dual-defect AgBiO3/DCN S-scheme heterojunction was constructed to overcome the sluggish charge separation and transfer issue and showed exceptional photodegradation performance towards norfloxacin (NFL) pollution under the visible light. The degradation efficiency of NFL reached 95.30 % within 120 min respectively, the rate constant was 3.64 times higher than that of defective g-C3N4 (DCN). The systematically characterizations proved that the enhanced photocatalytic activity was benefited from optimized band structures, improved carrier separation efficiency, due to dual defects and S-scheme heterojunction in AgBiO3/DCN. the intermediate degradation products and degradation pathway of NFL were speculated by UPLC-HRMS, and the environmental toxicity degree of degradation products was analyzed according to the T.E.S.T software. The charge transfer pathway was confirmed as an S-scheme mechanism through a combination of band structure analysis, alongside electron paramagnetic resonance (EPR) experiments.The quenching experiments and ESR analyses indicated that h+ and O2•− radicals played predominant roles. The efficient and stable photocatalytic NFL degradation efficiency and broad environmental adaptability proved potential practical application. This work may shed light on designing new dual-defect heterojunction with photocatalytic antibiotic removal capability in the innovative water treatment process.

Temperature-induced evolution of CuOx clusters in CuOx/TiO2 catalyst for boosting auto-exhaust oxidation

Developing non-noble metal oxides, replacing platinum group catalysts for auto-exhaust purification, where their usage amount exceeds 40 % of global demand, remains a challenge. Herein, we presented a combined approach on the synthesis and application of robust CuOx/TiO2 catalysts with ultra-fine CuOx clusters (ca. 1 nm). The strong interaction between CuOx and TiOx induces favorable interfacial charge accumulation, facilitating the extraction of the interfacial oxygen atoms in Cu2-x-O-Ti4-y chains and the surface lattice oxygen on CuOx clusters. Isotope 18O2 experiments and DFT calculations jointly confirmed that these oxygen atoms preferentially participate in the oxidation through the Mars-van Krevelen mechanism below 250 °C. The resulted oxygen vacancies facilitate the adsorption and activation of O2 molecules, which will participate the oxidation above 250 °C through Eley-Rideal mechanism. The increase in the temperature also drives the synergy of active oxygen species in the interfacial Cu2-x-O-Ti4-y bond chains and on CuOx clusters, cooperatively promoting the conversion of NO to NO2. As a result, the CuOx/TiO2 catalyst exhibits exceptional catalytic performance in soot oxidation, with a four-fold higher reaction rate (4.17 μmol g−1 min−1) than that of single-atom Cu₁-TiO2 catalyst. Such findings provide a novel strategy for the advancement of Cu-based cluster catalysts in environmental applications.

Electrochemical detection of human papillomavirus DNA based on an ultrasensitive electrochemical sensing platform using N-graphene paper

Human papillomavirus (HPV) is the primary cause of cervical cancer, a major global health concern affecting women worldwide. Early detection of high-risk HPV genotypes is crucial for timely intervention and reducing disease burden. However, current detection methods often lack sensitivity, speed, or cost-effectiveness, especially in resource-limited settings. This work addresses this critical need by developing an ultrasensitive electrochemical biosensing platform based on nitrogen-doped graphene paper electrodes for quantifying high-risk HPV16 DNA sequences. The N-graphene nanohybrid, fabricated via simple solvothermal treatment of biomass-derived graphene oxide, demonstrated significantly enhanced electrical and electrocatalytic properties compared to undoped graphene. DNA detection was achieved through characteristic oxidation signals of guanine bases, which displayed a wide linear dynamic range (0.5–100 μg/mL), low detection limit (75 pg/mL), and excellent reproducibility (relative standard deviation <3.5 %). Detailed spectroscopic and electrochemical analyses revealed the key roles of pyridinic nitrogen defects in improving interfacial charge transfer kinetics and mitigating biofouling issues. This synergistic combination of high electrical conductivity and versatile surface functionality paves the way for equipment-free, point-of-care genosensor devices tailored for quantitative biomarker screening in resource-constrained environments.

Toward the Rechargeable Aqueous Zinc Ion Batteries with Improved Overall Performance: Electrolyte with Surface Adsorptive Additive.

Aqueous zinc-ion batteries (AZIBs) with slightly acidic electrolytes process advantages such as high safety, competitive cost, and satisfactory electrochemical performance. However, the failure behaviors of both electrodes, regarding zinc dendrite growth, interfacial parasitic reactions, and the collapse of cathode materials hinder the practical application of ZIBs. To alleviate the issues of both anode and cathode at the same time, D-xylose (DX) is introduced to the electrolyte as a multifunctional additive. As a result, the side reaction of the anode is suppressed and the metallic deposition behavior is regulated due to the hydrogen bonding network reconstruction and preferential surface adsorption of DX; for the MnO2 cathode, the DX adsorption can help the interfacial charge transfer and increase the reactive sites. Benefiting from these merits, DX-optimized Zn//Zn battery displays reveal a prolonged lifespan of 6912h and an ultra-high cumulative capacity of 17.28Ahcm-2 at 5mAcm-2. With the function of water reactivity suppression, the Coulombic efficiency reaches 99.91% at 2mAcm-2; the Zn||MnO2 full batteries exhibit excellent cyclability over 2000 cycles at 5C with an increased capacity of 118.9mAhg-1, indicating the dual functions to both of the electrodes for AZIBs.

Ultra-sensitive zinc cobaltate assembled on N-rich carbon nitride electrochemical sensor for the detection of paraquat in food samples

BackgroundParaquat (PQ) from agricultural waste cause contamination in water bodies, groundwater, soil, and foods has received increasing attention regarding health safety. On-site-based detection is much needed along with rapid results, selectivity and sensitivity, which can be achieved through an electrochemical-based sensor. MethodsThis work provides, an electrochemical sensor based on zinc cobaltite (ZnCo2O4) nanostructure strongly attracted through electrostatic interaction with the carbon nitride (C3N5; CN) nanosheets modified on a glassy carbon electrode (GCE) for the determination of paraquat (PQ). The strong immobilization of ZnCo2O4 over CN2 on GCE synergistically shows excellent sensing of PQ due to high interfacial charge transfer effect. Significant findingsIn addition, the electrochemical studies were performed using CV and DPV analysis which exhibits a good limit of detection (7.6 nM) and sensitivity (0.201 µA cm-2) towards PQ detection. Furthermore, the modified electrode was applied practically in real food samples for PQ detection with excellent recoveries.

A novel 0D/3D Z-Scheme heterojunction ZnS/MIL-88(A) with significantly boosted photocatalytic activity toward tetracycline

Coupling two different photocatalytic materials to construct a heterojunction is a preferable strategy for obtaining the composite photocatalyst with high activity. Herein, a novel 0D/3D Z-scheme heterostructure ZnS/MIL-88(A) was constructed by anchoring 0D ZnS nanoparticles on the surface of the 3D MIL-88(A). The prepared ZnS/MIL-88(A) was characterized by using FT-IR, XRD, SEM, UV–vis and XPS. The photodegradation of tetracycline (TC) was conducted under the irradiation of visible light to evaluate the photocatalytic performance of ZnS/MIL-88(A). The creation of the Z-scheme heterostructure between ZnS and MIL-88(A) enables ZnS/MIL-88(A) to exhibit excellent visible-light absorption ability and dramatically boost separation and transfer of the photo-induced charge carriers. Compared with MIL-88(A), ZnS/MIL-88(A) shows prominently enhanced photocatalytic activity toward tetracycline, achieving a TC degradation rate of 94 %. The highest photodegradation rate constant (0.02083 min−1) of TC by ZnS/MIL-88(A) is 7.77 and 12.33 folds as large as those by MIL-88(A) and ZnS, respectively. After five cycles of reuse, ZnS/MIL-88(A) shows only a slightly decreased TC removal rate, presenting excellent photo-stability. Furthermore, the Z-scheme interfacial charge migration mode and the photocatalytic mechanism of ZnS/MIL-88(A) were discussed according to the band position as well as the identification result of the active species. The radicals ·O2− and ·OH generated in photocatalysis serve as major reactive species to decompose TC. This work provides a new way for designing efficient composite photocatalysts.

Photocatalytic degradation of norfloxacin antibiotic by a novel Cu-ZnO/BiOI/Bi2WO6 double Z-type heterojunction: Performance, mechanism insight and toxicity assessment

A novel double Z-type Cu-ZnO/BiOI/Bi2WO6 photocatalyst was synthesized using one-pot hydrothermal method. The effects of Bi2WO6 and Cu-ZnO contents, antibiotic concentration, catalyst dosage, solution pH value, coexisting ions, antibiotic types, mixed antibiotic types, water source and light source on the catalytic performance of the Cu-ZnO/BiOI/Bi2WO6 were investigated. Remarkably, under visible light irradiation, the removal rate of 20 mg/L norfloxacin reached 94.32 % within 120 min using the optimized Cu-ZnO/BiOI/Bi2WO6 photocatalyst, and its pseudo-first-order reaction rate constants were 5.63 and 1.80 times higher than those of BiOI and BiOI/Bi2WO6, respectively. The toxicity prediction and experimental findings indicated that the toxicity of the degraded norfloxacin (NOR) solution was notably diminished. The Cu-ZnO/BiOI/Bi2WO6 catalyst exhibited excellent salt tolerance, high reusability stability, universality and spectral response. Outstanding photocatalytic performance of Cu-ZnO/BiOI/Bi2WO6 photocatalyst is primarily due to the co-recombination of Cu-ZnO and Bi2WO6 on BiOI, which increases the surface area and active sites of the catalyst. More importantly, the double Z-type heterojunction, created through the intimate union of the semiconductor boundary within the composite catalyst, enhances the interface charge transport efficacy and the efficiency of separating photogenerated carriers. Finally, in conjunction with a diverse range of experimental methodologies, the degradation pathway of NOR through the Cu-ZnO/BiOI/Bi2WO6 composite catalyst and the electron transfer mechanism within the double Z-type heterojunction have been comprehensively elucidated. This study provides a pioneering reference for optimizing BiOI-based heterojunction catalysts and addressing antibiotic-contaminated wastewater treatment.

Effect of charge inversion on the electrokinetic transport of nanoconfined multivalent ionic solutions

Understanding the effects of phenomena occurring at electrically charged interfaces, such as charge inversion (CI), is crucial for enabling electroosmosis as an efficient transport mechanism in nanodevices. Here, we employ molecular dynamics (MD) simulations to systematically analyze the effect of CI on the electrokinetic transport of multivalent ionic solutions confined in amorphous silica nanochannels. We employ mixtures of monovalent and multivalent counterions while fixing the total ionic concentration to establish correlations between observed phenomena and the amount of multivalent ionic species in the electrolyte solution. The results show that the development of CI is related to a decrease in the mobility of the fluid layers adjacent to the charged surface. In addition, we observe that interfacial overcharging disrupts the water molecular orientation in the fluid layers adjacent to the channel walls. From the non-equilibrium MD simulations of electro-osmotic flow, we disclose the influence of phenomena related to the presence of CI. In particular, flow reversal occurs in scenarios involving CI due to increased local viscosity and a higher concentration of coions within the hydrodynamically mobile and electrokinetically active region of the charged interface. We also find that the magnitude of the wall zeta (ζ) potential displays a monotonic increase with the development of CI in the system. Moreover, we explain why positioning the wall ζ potential at an imaginary (slip) plane, which separates the hydrodynamically mobile and immobile fluid, is misleading.

Advancements in Rechargeable Zn-Air Batteries with Transition-Metal Dichalcogenides as Bifunctional Electrocatalyst.

This review covers recent progress on transition metal dichalcogenides (TMDs) as bifunctional electrocatalysts for Zinc-air batteries (ZABs), emphasizing their suitable surface area, electrocatalytic active sites, stability in acidic/basic environments, and tunable electronic properties. It discusses strategies like defect engineering, doping, interface, and structural modifications of TMDs nanostructures for enhancing the performances of ZABs. Zinc-air batteries are promising energy storage devices owing to their high energy density, low cost, and environmental friendliness. However, the development of durable and efficient bifunctional electrocatalysts is a major concern for Zn-air batteries. In this review, we summarize the recent progress on transition metal dichalcogenides (TMDs) as bifunctional electrocatalysts for Zn-air batteries. We discuss the advantages of TMDs, such as high activity, good stability, and tunable electronic structure, as well as the challenges, such as low conductivity, poor durability, and limited active sites. We also highlight the strategies for fine-tuning the properties of TMDs, such as defect engineering, doping, hybridization, and structural engineering, to enhance their catalytic performance and stability. We provide a comprehensive and in-depth analysis of the applications of TMDs in Zn-air batteries, demonstrating their potential as low-cost, abundant, and environmentally friendly alternatives to noble metal catalysts. We also suggest future directions like exploring new TMDs materials and compositions, developing novel synthesis and modification techniques, investigating the interfacial interactions and charge transfer processes, and integrating TMDs with other functional materials. This review aims to illuminate the path forward for the development of efficient and durable Zn-air batteries, aligning with the broader objectives of sustainable energy solutions.

Electrostatic Gating-Dependent Multiple Band Alignments in Ferroelectric α-In2Se3/α-Te van der Waals Heterostructures.

The two-dimensional ferroelectric van der Waals (vdW) heterojunction has been recognized as one of the most promising combinations for emerging ferroelectric memory materials due to its noncovalent bonding and flexible stacking of various materials. In this work, the first-principles calculations were performed to study the stable geometry and electronic structure of α-In2Se3/α-Te, incorporating the vdW correction via the DFT-D2 method. The reversal of the polarization direction in α-In2Se3 can induce a transition in the heterostructure from metallic to semiconductor, accompanied by a shift from type-III to type-I band alignment. These changes are attributed to variations in interfacial charge transfer. Analysis of the modulation effects of external electric fields reveals that the P↑ α-In2Se3/α-Te configuration maintains metallic, whereas the P↓ α-In2Se3/α-Te configuration exhibits a linear reduction in band gap. Furthermore, both heterostructural configurations will undergo transitions to type-II band alignment transitions at 0.2 V Å-1 and within a range from 0.2 to 0.3 V Å-1 under external electric fields. Our findings offer valuable insights for applications such as ferroelectric memory and static gate devices with multiband alignment.

In-situ synthesis of Fe phosphate layer on the porous hematite nanocube for efficient photoelectrochemical water splitting

Hematite (α-Fe2O3) is considered as an ideal photoanode material in photoelectrochemical (PEC) water splitting system due to its suitable band gap, excellent stability and abundant reserves. However, the actual PEC water oxidation performance of α-Fe2O3 is greatly limited by its severe charge recombination and sluggish water oxidation kinetics. Here, an in-situ generated Fe phosphate (Fe-Pi) coating strategy is applied on the surface of porous hematite nanocube (Fe2O3 NC) to realize PEC water oxidation effectively. The obtained Fe-Pi/Fe2O3 NC photoanode exhibits a remarkable PEC property with a photocurrent density of 2.7mAcm-2 at 1.23V vs. RHE, which was about 5.7-fold enlarged compared to the pristine nanorod-like hematite (Fe2O3 NR) photoanode. Detailed studies have shown that the porous Fe2O3 NC possesses an enhanced ability in light absorption and charge separation than the traditional Fe2O3 NR photoanode. In addition, the in-situ loading of Fe-Pi layer as a co-catalyst can not only effectively passivate the surface trapping states of Fe2O3 NC and suppress interfacial charge recombination, but also quickly extract the holes to participate in the water oxidation reaction. Our study suggests that the further surface modification based on morphological engineering is an effective strategy to improve the PEC performance of hematite.

Construction of magnetically separable S-scheme BiFeO3/Cl-g-C3N4 heterostructure photocatalyst for simultaneous removal of Cr(Ⅵ) and tetracycline in aqueous solution: Performance and mechanism insight

A green, efficient and recyclable magnetic BiFeO3/Cl-g-C3N4 photocatalyst was prepared for the simultaneous removal of Cr(Ⅵ) and tetracycline (TC) from water by wet chemical and thermal synthesis methods. Experimental results revealed that BiFeO3/Cl-g-C3N4 achieved a removal efficiency of 96.1 % for Cr(Ⅵ) and 98.2 % for TC under visible light irradiation for 50 min at pH 6. The results of the work function, differential charge density, UV–vis DRS, PL, PC and EIS tests indicate the formation of S-scheme heterojunctions between BiFeO3 and Cl-g-C3N4, which exhibits superior carrier separation and migration efficiency. The evidence for interfacial charge transfer from BiFeO3 to Cl-g-C3N4 within BiFeO3/Cl-g-C3N4 was further corroborated by means of ISIXPS, EPR and KPFM. Moreover, calculations of the density of states demonstrate that the introduction of Cl enhances the reduction capability of BiFeO3/Cl-g-C3N4. Results from ESR tests and trapping experiments has demonstrated that the singlet oxygen (1O2) and electrons are the primary active species. Furthermore, the high removal rates of TC and Cr(VI) from industrial wastewater and groundwater, coupled with the lower ecotoxicity of TC degradation intermediates, indicate that BiFeO3/Cl-g-C3N4 has the potential for practical applications. After five cycles, the BiFeO3/Cl-g-C3N4 still removed 90.5 % of TC and 96 % of Cr(Ⅵ).

Fe3O4 encapsulated in hierarchically porous nitrogen-doped graphitic carbon layers for efficient oxygen reduction reaction: Enhanced intrinsic activity via directional interfacial charge transfer

Constructing efficient electrocatalysts for the oxygen reduction reaction (ORR) is crucial for the commercialization of metal-air batteries. Iron oxide-based catalysts exhibit promising potential for ORR. However, addressing the issue of inferior catalytic performance is essential, and a comprehensive understanding of the catalytic mechanism of iron oxide-based catalysts is also lacking. In this study, we present Fe3O4 nanoparticles encapsulated in N-doped graphitic carbon layers (NGC) hosted by hierarchically porous carbon (Fe3O4@NGC), achieved through a facile dual melt-salt template strategy. The encapsulation of Fe3O4 nanoparticles protects them from corrosion and exfoliation, endowing the catalysts with superior stability. Density functional theory (DFT) calculations discover that the electronic interaction between Fe3O4 nanoparticles and N-doped graphitic carbon layers induces directional interfacial electron transfer, which effectively modulates the surface electronic structure to improve the binding ability to O2, weaken the OO bond, and optimize the adsorption of intermediates, thus boosting the intrinsic activity. DFT unveils that the C atoms nearest to graphitic-N in NGC are active sites. Finally, the synergistic effects of Fe3O4 nanoparticles and NGC result in outstanding ORR performance and superior stability and methanol tolerance of Fe3O4@NGC, with a half-wave potential of 0.89 V, surpassing that of Pt/C by 50 mV. Fe3O4@NGC also shows better performance than Pt/C when used as the air-electrode catalyst in zinc-air battery.

Z-scheme heterostructures confining rGO/protonated C3N5 junction supported CoCu LDH positive electrode and Fe3O4 negative electrode for supercapacitors

CoCu LDH stabilized reduced graphene oxide-linked N-rich protonated C3N5 (CoxCuy@rGO/P-CN) as a power source Z-scheme nanocomposite was rationally tailored engineered an electrodeposition approach. The electrochemical performance was regulated by adjusting the electrodeposition potential and manipulating the Co/Cu molar ratio. Hence, affording compelling evidence for fine-tuning the performance of pseudo-active compounds. Benefiting from abundant heterointerfaces and synergistic effects between LDH nanoarrays and rGO/P-CN heterojunction, the hierarchical ‒1.2V Co3Cu1@rGO/P-CN Z-scheme positive electrode achieves a higher capacitance of 1184 F g–1 at 1 A g–1 and good rate capability performance. Theoretical simulation outcomes illustrate that the Co3Cu1@rGO/P-CN nanocomposite has higher electronic conductivity and superior electronic transition capability, originating from robust interactions between valence and conduction bands, interfacial charge transfer, and built-in electric field at the LDH/rGO/P-CN interface. We also explore the Fe3O4@rGO/P-CN Z-scheme as a negative electrode material via a simple annealing process with a capacitance of 402 F g–1 at 1 A g–1 and an enhanced cyclic performance. Consequently, the as-assembled ‒1.2V Co3Cu1@rGO/P-CN//Fe3O4@rGO/P-CN asymmetric supercapacitor (ASC) cell acquires a remarkable energy density of 63.4 Wh kg–1 at 750 W kg–1 and displays an exceptional cycling activity with 88% retention after 11,000 cycles.

Interface-engineered Ni(Fe/Al)-LDHs/g-C3N4 nanosheets with metallic Fe/Al[sbnd]N bonds for efficient photocatalytic degradation of tetracycline hydrochloride

To improve the photogenerated electron–hole separation efficiency and the number of reactive oxygen species of g-C3N4 in visible light. Herein, an interface-engineered Ni(Fe/Al)-LDHs/g-C3N4 nanosheets with Fe/AlN bonds were prepared, which shows highly enhanced photocatalytic degradation performance with excellent structural stability. The interfacial structure of g-C3N4 was precisely regulated by metal Fe/Al on the surface of layered double hydroxides (LDHs), which could form Fe/AlN bonds as the interfacial charge transfer channels. In addition, the metal Ni and Fe/Al on the surface of LDHs nanosheets can furnish more photocatalytic active sites and interface synergy. The obtained 7 %NiFe-LDHs/g-C3N4 owns the degradation rate of 99.23 % for tetracycline hydrochloride (TCH) in visible light. This work highlights a rational interface engineering strategy for the formation of a composite structure with interface interaction for efficient photocatalysts.

In Situ Driven Formation of Anatase/Brookite/Rutile Heterojunction N/TiO2 Nanocrystals as Sustainable Visible-Light Catalysts.

Visible-light active anatase/brookite/rutile (A/B/R) ternary N-doped titania (N/TiO2) crystals are successfully prepared by a facile sol-gel method using titanium butoxide and benign N-dopant source, guanidinium chloride. Systematically varying the aging time (1, 4, 8, and 12 d), its influence on physicochemical properties of as-obtained spherical heterojunction nanomaterials is studied. Detailed characterizations confirm that a substantial amount of anatase (88% to 50%) is transformed to rutile (2% to 38%) via intermediate brookite phase (9% to 25%) as the function of aging time; not only the A/B/R phase content of the samples is tuned by sol-gel aging time of the precursors solution but also their optical-response and methylene blue photocatalytic properties are profoundly dictated. Notably under visible-light irradiation, the photostable rutile rich mesoporous A/B/R triphasic N/TiO2 (50% A, 12% B, 38% R) aged for 12 d demonstrates higher degradation activity (97%) with a faster degradation rate (0.033 min-1) than both lesser aged N/TiO2 and undoped titania. This enhancement is attributed to the synergistic effect of interstitial-N-doping and optimal A/B/R interfacial charge transfer that leads to higher light absorption, lower bandgap energy and well-separated charge carriers. The current work provides a new perspective for designing highly active visible-light heterostructure nanomaterials with controllable phase composition.

Ultra-fine carbon decorated TiO2/C/g-C3N4 hybrid for strong physical adsorption and efficient photodegradation of pollutants

Enhancement in the visible light absorption and efficient interfacial charge transfer is crucial for optimizing photocatalytic efficiency in the degradation of pollutants such as methyl orange (MO) and formaldehyde. This study focuses on the properties of a TiO2/C/g-C3N4 hybrid efficient photocatalyst is developed by employing an air calcination method to deposit graphitic nitride (g-C3N4) onto a carbon-modified TiO2 surface. The characterization techniques, including high-resolution transmission electron Microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), were used to provide a comprehensive understanding of the material’s structural, morphological, thermal, and chemical properties. This hybrid catalyst is specifically engineered for the efficient decomposition of methyl orange (MO) and formaldehyde, demonstrating a significant increase in photocatalytic activity. The TiO2/C/g-C3N4 photocatalyst also exhibits an enhanced specific surface area of 181.2 m2/g, which facilitates increased physical adsorption and photo-catalytic active sites. Experimental results confirm that this catalyst effectively adsorbs MO physically even in the dark without degradation. Combining physical and photo-catalytic functions, this catalyst degrades 94 % of MO within 180 min with the initial concentration 0.2 mol/L of MO, and achieves almost 100 % decolorization of MO under visible light irradiation. Notably, the catalyst retains its high activity after 4 cycles of MO degradation, underscoring its durability and consistent performance. Additionally, the hybrid catalyst features a staggered type-II energy level configuration, which effectively enhances charge separation and boosts photocatalytic efficacy. The incorporation of an ultrafine carbon layer further augments electron mobility towards the surface, crucial for effective catalytic reactions. This study paves the way for future development of highly efficient photocatalytic materials for environmental purification.