High Charge Separation Efficiency Research Articles

Anchoring AuCu alloy nanoparticles on TiO2 nanosheets: Exploiting synergistic effects and directed electron transfer for enhanced photocatalytic H2 evolution

AuCu/TiO2 composite photocatalysts were prepared by anchoring AuCu nanoparticles (NPs) on TiO2 nanosheets using a simple photoreduction method. Visible diffuse reflectance spectra indicated that the AuCu/TiO2 significantly enhanced light absorption in the visible region. Through photoluminescence spectroscopy and steady-state surface photovoltage experiments, AuCu/TiO2 exhibits an excellent photogenerated electron transfer rate. In addition, photoelectrochemical experiments showed that AuCu/TiO2 had a high photogenerated charge separation efficiency. AuCu/TiO2 (1.0 wt%) exhibited the best performance, under full spectrum, the hydrogen evolution rate is 33.94 mmol g−1 h−1, which is 1.59 times and 1.66 times higher than that of single metal Au/TiO2 (1.0 wt%) (21.28 mmol g−1 h−1) and Cu/TiO2 (1.0 wt%) (20.42 mmol g−1 h−1), respectively. The results showed that AuCu NPs greatly enhanced the photocatalytic performance of the composite photocatalysts.

The Role of Thermally Activated Charge Separation in Organic Solar Cells

AbstractIn recent years, organic solar cells (OSCs) have shown high power efficiencies approaching 20%. However, the fundamental mechanisms of charge separation in these highly efficient devices have been a subject of intensive debates. Here, the charge separation efficiency (CSE) is extensively investigated across a wide range of blend systems with different energetic offsets. The findings unveil the temperature‐dependent nature of charge separation in low‐offset systems, emphasizing its significant contribution to the overall CSE. An intriguing inverse correlation between CSE and charge separation activation energy in relation to the offset is also observed. These results shed new light on the factors underlying the high CSE observed in the state‐of‐the‐art devices.

Nickel-doped and surface fluorinated tungsten trioxide photoanode with enhanced photoelectrochemical water oxidation

To improve the slow charge transfer and high electron-hole recombination rate of tungsten trioxide (WO3), a nickel-doped and surface fluorinated WO3 photoanode is proposed. Compared with the unmodified and one-step modified WO3 photoanodes, the co-modified F/Ni-WO3 with two steps exhibits superior photoelectrochemical (PEC) performance with a significantly high photocurrent density of 1.03 mA/cm2 compared to 0.51 mA/cm2 of bare WO3 at 1.23 V vs. RHE. Ni doping can accelerate the kinetics of water oxidation and extend the light absorption range of the WO3 photoanode, while surface fluorination can enhance the surface electronegativity and hydrophilicity of the WO3 photoanode. The synergistic influence of the Ni doping and surface fluorination results in a lower carrier transport impedance, higher charge separation efficiency and larger electrochemically active surface of the WO3 photoanode which eventually contribute to the enhanced PEC performance for water oxidation.

Fabrication of a 2D/2D g-C3N4@ZnTDA nanosheets catalyst for highly efficient degradation of 2,4-dibromophenol and improved flame retardancy of polyurethane foam

High charge separation and transfer efficiency are considered as key factors of photocatalysts in wastewater treatment applications. In this work, a high performance photocatalyst g-C3N4@ZnTDA was designed and applied through a facile solvothermal strategy. The microstructural, morphological, physicochemical, and photoelectrochemical properties of g-C3N4@ZnTDA were fully characterized. The photocatalytic activity of g-C3N4@ZnTDA nanoparticles under visible light source in degrading the 2,4-dibromophenol(2,4-dB) contaminants was also successfully studied. Additionally, the g-C3N4@ZnTDA composite demonstrates easy operation and good regeneration ability, making it highly promising for the efficient removal of phenolic pollutants from wastewater. Besides, a novel reutilization method for used catalyst as flame retardant and for PU foams was successfully testified. The MCN-3 as a fire-safety coating could reduce the heat release and improve flame retardancy of PU composites. This work opens a new window for valuable inspiration and structural design of reutilized MOF composites.

Z-scheme heterojunction enhanced photocatalytic performance for CO2 reduction to CH4.

Due to the high charge separation efficiency leading to high photocatalytic activity, there has been significant interest in enhancing the charge separation ability of photocatalysts by controlling the heterojunction structure. To investigate the effect of the heterojunction structure on the photocatalytic performance of composite catalysts and understand its corresponding mechanism, a Z-scheme ZnFe2O4/ZnO/CdS heterojunction was constructed using the ultrasound method and used for CO2 photoreduction. The Z-scheme heterojunction catalyst demonstrates elevated photocatalytic and charge separation efficiencies. Specifically, the conversion rate for the photocatalytic conversion of CO2 to CH4 reaches 105.9 μmol g-1 h-1, surpassing that of the majority of previously reported semiconductor photocatalysts like ZnFe2O4/CdS. This research offers a fresh perspective on the development of innovative heterojunction photocatalysts and broadens the utilization of ternary composite materials in CO2 photoreduction.

Enhancing the photoelectrochemical performance of TiO2 photoanode by employing carbon nanoparticles as electron reservoirs and photothermal materials.

Photoelectrochemical (PEC) water splitting is regarded as a potential technique for converting solar energy. However, the fast charge recombination and slow water oxidation kinetics significantly have hindered its practical application. It is found that an elevation in operation temperature can activate the charge transport in the photoanodes. Here, a strategy was performed that carbon nanoparticles were employed to TiO2 nanorods, acting as electron reservoirs as well as photothermal materials. More specifically, a record photocurrent density of 1.62mAcm-2 at 1.23V vs. RHE has been achieved, accompanied by a high charge separation efficiency of 96% and a long-term durability for 8h. The detailed experimental results reveal that under NIR light irradiation, the synergistic effect between electron storage and temperature rise leads to accelerated charge transport in the bulk and water oxidation kinetics on the surface. This research offers a new perspective on how to boost the PEC performance of photoelectrodes.

Non-enzymatic g-C3N4 supported CuO derived-biochar based electrochemical sensors for trace level detection of malathion

Malathion (MALA), a widely used insecticide, even at trace levels exhibits deleterious effects towards respiratory tracts, and nervous system, necessitating its detection. Herein, we have offered non-enzymatic trace level monitoring of MALA using g-C3N4 supported CuO-derived biochar. The present B-CuO/g-C3N4 based electrochemical sensor is synthesized using hydrothermal approach followed by calcination at high temperature. The result unveiled the strong <pi-pi> interactions, high charge separation efficiency, significant porosity leading to excellent electrochemically active surface area 9.88 × 10−5 cm2 with least charge transfer resistance (RCT) value of 35.2 K Ω. The B-CuO/g-C3N4 based nanocomposite offered excellent complex formation ability with MALA and square wave anodic stripping voltametric method (SWASV) generates an enhanced electrochemical signal due to oxidation of MALA. Following all necessary optimizations, the sensor was capable to exhibit limit of detection (LOD) value of 1.2 pg mL−1 with R2 = 0.968. The modified biosensor offered its potential towards detection of MALA in apple and tomato samples with a recovery ranging from 87.64 to 120.59%. This novel B-CuO/g-C3N4 ternary nanocomposite provides non-enzymatic detection of MALA having excellent electrochemical properties and hence opens new pathways for exploring the use of biochar in other electrochemical applications.

A donor-acceptor π-stacked multifunctional Eu-MOF based on a novel viologen-like photosensitive ligand: Degradation of tetracycline, photochromism, and photoluminescence

The photosensitive building blocks of photochromic MOFs are mostly 4,4′-bipyridine. However, the linear structure and kind of 4,4′-bipyridine derivatives limit the development of its properties and applications. Therefore, a “Y"-shaped 2,4,6-tri (4-pyridyl)-1,3,5-triazine derivative ([H3p-Batpt]Cl3, TPT) with high conjugation, bare nitrogen and oxygen sites that was selected as a novel photosensitive ligand to replace the traditional 4,4′-bipyridine ligand for photochromic MOFs. Then, [H3p-Batpt]Cl3 was combined with EuIII and terephthalic acid (H2TPA) to construct a multifunctional Eu-MOF [Eu2 (p-Batpt) (TPA)3(H2O)]n (1). 1 possess degradation of tetracycline (TC), photochromic and photoluminescence properties. The colored 1 (1P) after irradiation with UV–vis light (300 W, Xe-lamp) is difficult to fade due to donor-acceptor (D-A) π-π and radical-π interactions. In addition, 1 is used in photocatalysis because it is an excellent N-type semiconductor. The TC degradation rate of 1 can reach 67.42 % under visible light and be recycled six times. Interestingly, the TC degradation rate of 1P was 6.78 % higher than that of 1. Electrochemical tests show that 1P has higher charge separation efficiency and a smaller band gap. The free radicals capture and ESR experiments of 1 revealed that holes (h+) played a leading role in the photocatalytic degradation of TC. This research expands the application of photochromic MOFs and provides a reference for removing organic pollutants.

Role of oxygen vacancy enriched m-BiVO4/t-BiVO4 isotype heterojunction for enhanced photocatalytic degradation of rhodamine B dye and in ferroelastic to paraelastic phase transition

Mixed-phase isotype heterojunction oxide materials with superior photocatalytic activities have recently revealed a significant coupling between individual phases with controlled optical properties. Therefore, we focus on synthesizing a mixed-phase monoclinic-tetragonal (m-t) BiVO4 photocatalyst using hydrothermal method. The increased recombination rate of electron-hole (e−-h+) pairs limits the photocatalytic performance of monoclinic (m) BiVO4 photocatalysts. Therefore, effective spatial charge carrier separation can be improved by creating an isotype heterojunction between the phases m-BiVO4 and t-BiVO4. The precursor pH, mechanical grinding, and calcination temperature regulate the formation of m-t BiVO4. The phase fractions of the two phases in m-t BiVO4 sample are 85% monoclinic and 15% tetragonal. Herein, we demonstrate the optical properties and photocatalytic activity based on the crystal chemistry of m-BiVO4 and m-t BiVO4. Temperature-dependent Raman measurements suggest a second order ferroelastic monoclinic to paraelastic tetragonal phase transition above 530 K owing to optical phonon anharmonic coupling interactions. The small increase (5 °C) in Tc in m-t BiVO4 compared to m-BiVO4 is due to the coexistence of tetragonal and monoclinic phases. The optical band gap of m-t BiVO4 is larger than that of m-BiVO4. Additionally, the evaluation of BiVO4 photocatalytic activity over rhodamine-B (Rh-B) dye suggests that the m-t BiVO4 with 97.5% degradation efficiency is superior compared to m-BiVO4 with 89% degradation efficiency. This is because, the two phases (m and t) of BiVO4 form an isotype heterojunction interface, which results in a high charge separation efficiency, as demonstrated by photocurrent studies and electrochemical impedance spectroscopy. Moreover, oxygen vacancies tune the charge carrier dynamics through the modification of band edges. These findings regarding the isotype phase-junction mechanism provide possibilities for innovative ideas for highly efficient mixed-phase isotype heterojunction photocatalysts for wastewater remediation.

Novel and noble-metal-free CdIn2S4/MoB Schottky heterojunction photocatalysts with efficient charge separation for boosting photocatalytic H2 production

The construction of Schottky heterojunctions by selecting applicable metalloids and semiconductors is highly effective for improving the activity of semiconductors. Herein, we deposited CdIn2S4 on MoB by hydrothermal method to construct a noble metal-free and unreported CdIn2S4/MoB Schottky heterojunction for achieving high photocatalytic H2 production. In ultraviolet photoelectron tests, the Fermi level of the CdIn2S4/MoB composites exhibited a certain shift compared with CdIn2S4 and MoB, manifesting the rearrangement of the Fermi level and the formation of Schottky heterojunction. The formed Schottky heterojunction greatly promoted the electron migration from CdIn2S4 to MoB (proved by XPS tests) to obtain high charge separation efficiency (confirmed by PL and electrochemical tests). CdIn2S4/MoB composites possessed smaller H2 evolution overpotential and Tafel slope, which greatly promoted the release of H2 in the kinetics. Besides, CdIn2S4/MoB composites had higher light absorption capacity and larger specific surface area, which were for more conducive to H2 production. Ultimately, CdIn2S4/MoB composites had significantly improved H2 production activity. Among all composites, the activity of CdIn2S4/20MoB was the highest (463.53 μmol·g−1·h−1), which was 3.5 times that of CdIn2S4-1 %Pt. Besides, CdIn2S4/MoB composites possessed excellent stability in five experiments. Simultaneously, the formation of the Schottky heterojunction and its mechanism of promoting H2 production reaction were also thoroughly investigated. This work is the first to report that MoB could construct Schottky heterojunctions with sulfides for efficient photocatalytic H2 evolution, which is easily extended to sulfides other than CdIn2S4.

Layered oxyiodide CdBiO2I: An efficient visible light responsive and scalable photocatalyst

Developing high-performance visible-light driven photocatalyst (λ≥420 nm) makes significance for the efficient utilization of solar energy. Mass production and easy recycling are equally important for the practical application of powdery photocatalyst. However, it is challenging to meet the above requirements at the same time. In this work, we develop an efficient visible-light responsive layered oxyiodide CdBiO2I nanosheets prepared by a facile direct precipitation method at ambient atmosphere, and demonstrate its upgradable features well fitting potential application. CdBiO2I has a layered crystal structure consisting of [CdBiO2]+ layer and I– single layer, differing from that of BiOI composed of [BiO2]2+ layer and I- double layers. It displays an absorption edge of 520 nm in visible region, with a band gap of 2.52 eV. CdBiO2I has a large intrinsic effective mass difference of hole/electron, exceeding BiOI by 8-fold, which results in much higher charge separation efficiency and production of more reactive species (superoxide radicals and holes). The degradation efficiency of CdBiO2I nanosheets for tetracycline hydrochloride reaches 84% under the visible light irradiation within 1 h, in which the degradation rate is 10 times that of BiOI. In addition, mass production (12 g catalyst at one time) and immobilization onto porous polyurethane foam of CdBiO2I powder are also demonstrated, which indicates the scalable properties and easy recovery of the catalyst, highlighting the advantages of the current preparation method and prefiguring its potential in practical applications. This work may enlighten future research on the exploitation of solar-driven catalyst with high efficiency and strong practical applicability.

Efficiently enhanced degradation for the organic pollutants over GO/BiOI/NiWO4 with Z-scheme heterojunction and DFT studies

In this work, a series GO/BiOI/NiWO4 (n%GBINWO, n=5, 10, 15, 20) were hydrothermally prepared and applied as photocatalysts for the degradation of organic dyes under ambient conditions. The physico-chemical and microstructure of the studied samples were characterized by XRD, SEM, TEM, TG-DTG, XPS, UV-Vis, EIS, and N2-adsorption. Compared with pure NiWO4, the photocatalytic activity of BiOI/NiWO4 and GO/BiOI/NiWO4 were obviously enhanced, and the highest photocatalytic efficiency of 10 %GBINWO was observed to be 98.59 % (methylene blue, MB) under the optimized conditions (catalyst weight of 30 mg, pH of 3, 3 h, 30 °C). The excellent catalytic performance of the 10 %GBINWO was due to the existence of interfacial heterojunction, which endows the ternary composite with the large visible light capacity and high charge separation efficiency. Importantly, after the hybrid model constructed with NiWO4 (-1 1 1) and BiOI (0 0 2) was optimized via DFT calculations, a newly-formed bond of I-Bi-O-M (Ni and W), which promoted the transportation of the photogenerated electrons through newly-formed bridge was observed. Furthermore, the difference in degradation efficiency of various organic pollutants was related to the steric hindrance as well as the molecular structure. Moreover, •O2− was also confirmed as the key active species for 10 %GBINWO catalyzing the degradation process. Besides, the Z-scheme heterojunction between BiOI and NiWO4 was confirmed by TD-DFT calculations.

Regulating the Morphology Modification To Prepare the High Charge Separation Efficiency and Visible Light Responsive Dual-Type-II B-CN/H-TiO2/BS-CN Heterojunction for Wastewater Treatment.

For the conventional type-II heterojunction photocatalyst, their photocatalytic activity is affected by the limited separation efficiency of electron-hole pairs, exquisitely designed heterojunction photocatalysts are highly prospective materials for inducing charge transfer efficiently. Typically, enhancing the separation efficiency of electron-hole pairs in photocatalysts has been a formidable challenge. Here, the hollow mesoporous TiO2 (H-TiO2), the bulk g-C3N4 (B-CN), and g-C3N4 with bamboo shape (BS-CN) are prepared by simple processes. Among them, it is surprising to find that the band structure of g-C3N4 can be regulated and controlled by adjusting its structure. The B-CN/H-TiO2/BS-CN (CNTOCN) dual-type-II heterojunction photocatalyst and B-CN/H-TiO2 (CNTO) type-II heterojunction photocatalyst are designed to improve the separation efficiency of electron-hole pairs. The superiority of CNTOCN dual-type-II heterojunction photocatalyst is demonstrated by the photocatalysis experiment, the band structure analysis, and the photoelectric characterization. The results show that CNTOCN (0.8428 h-1) has much higher photocatalytic activity than H-TiO2 (0.0812 h-1), B-CN (0.3569 h-1), and CNTO (0.5934 h-1). The improvement of photocatalytic activity is ascribed to the establishment of the dual-type-II heterojunction charge transfer mechanism. This work presents an approach to designing efficient dual-type-II heterojunction photocatalysts for the sustainable conversion of solar energy to photodegrade dyes in dyeing wastewater.

The Ferroelectric Effects of Rhombohedral and Tetragonal BiFeO3 in Photoelectrochemical Water Splitting.

The phase of BiFeO3 (BFO) as well as its domain configuration can be tuned by strain engineering. Phase change may greatly influence the properties of the polarization field and hence charge separation. However, the photoelectrochemical properties of different BFO phases have rarely been addressed. Here, the photoelectrochemical study of tetragonal (T-) and rhombohedral (R-) phase BFO films was conducted under visible light illumination. The photocurrent density of R-BFO is 5 times that of T-BFO. A ferroelectric domain study shows that T-BFO features single domain structure in contrast to the polydomain structure of R-BFO. Higher charge separation efficiency is achieved in R-BFO, dominated by the domain walls as conducting pathways for efficient charge separation and transfer. This work provides a fundamental understanding of the photoelectrochemical properties of T- and R-BFO, offering valuable insights for the development of BFO-based materials for solar energy conversion.

Ag-catalyzed strain engineering in ZnO for tailoring defects towards bacterial inactivation and removal of organic dyes for environmental sustainability

This study explored Ag-guided strain formation in ZnO that can manipulate defects in related properties, which are helpful in enhancing the photocatalytic performance of ZnO. Ag@ZnO nanosheets were synthesized with varying Ag concentrations (0–5 at%) through a cost-effective hydrothermal method and employed for the efficient removal of environmentally concerning dyes, namely methylene blue (MB), methyl orange (MO), and rhodamine B (RhB), under natural sunlight radiation. Microscopic images (SEM and TEM) revealed the nanoplates regardless of the Ag concentrations. The XRD pattern confirmed the pure phase of the hexagonal wurtzite structure of ZnO, while the crystallite size decreased from 25 to 20 nm, augmented with the bright field-TEM images. The energy bandgap, Eg, decreased from 3.24 to 3.18 eV, as Ag concentration increased from 0 to 5 at%. The highest photocatalytic efficiency of Ag@ZnO:5 at% was achieved to be ∼93 %, ∼97.5 %, and ∼98 % for MO, MB, and RhB, respectively. The enhanced photocatalytic activity of Ag@ZnO:5 at% was attributed to the high charge separation efficiency and many active sites due to the surface integration of Ag atoms and defects states. Ag@ZnO:5 at% nanoplates showed significant inactivation against environmentally transmitted pathogenic bacteria within 30 min. These findings underscore the significant potential of Ag@ZnO photocatalysts for sunlight-driven removal of organic pollutants, aligning with the sustainability goals advocated by the United Nations. The outcomes of this research contribute valuable insights into the development of efficient photocatalytic materials for environmental pollution remediation.

3D/3D Bamboo Charcoal/Bi2WO6 Bifunctional Photocatalyst for Degradation of Organic Pollutants and Efficient H2 Evolution Coupling with Furfuryl Alcohols Oxidation.

Photocatalysis is one of the most promising pathways to relieve the environmental contamination caused by the rapid development of modern technology. In this work, we demonstrate a green manufacturing process for the 3D/3D rod-shaped bamboo charcoal/Bi2WO6 photocatalyst (210BC-BWO) by controlled carbonization temperature. A series of morphology characterization and properties investigations (XRD, SEM, UV-vis DRS, transient photocurrent response, N2 absorption-desorption isotherms) indicate a 210BC-BWO photocatalyst with higher charge separation efficiency, larger surface area, and better adsorption capacity. The excellent photocatalytic performance was evaluated by degrading rhodamine B (RhB) (98.5%), tetracycline hydrochloride (TC-HCl) (77.1%), and H2 evolution (2833 μmol·g-1·h-1) coupled with furfuryl alcohol oxidation (3097 μmol·g-1·h-1) under visible light irradiation. In addition, the possible mechanisms for degradation of organic pollutants, H2 evolution, and furfuryl alcohol oxidation were schematically investigated, which make it possible to exert photocatalysis by increasing the active radical. This study shows that the combination of bamboo charcoal and bismuth tungstate can be a powerful photocatalyst that rationally combines H2 evolution coupled with furfuryl alcohol oxidation and degradation of pollutants.

Synthesis of palladium-decorated defective tungsten oxide heterostructures with enhanced photothermal catalytic activity for hydrodeoxygenation of vanillin

The selective hydrodeoxygenation (HDO) of sustainable lignocellulosic biomass plays a pivotal role in the conversion of biomass into high-value fuels and chemicals. Nevertheless, HDO for biomass upgrading always demands high temperatures and high hydrogen (H2) pressure. Photothermal catalysis has been recognized as an effective approach for boosting chemical reactions under mild conditions while maintaining superior selectivity. Herein, we report the design of palladium-decorated defective tungsten oxide (Pd/WO3-x) catalysts with enhanced photothermal catalytic performances for the efficient HDO of vanillin. Pd/WO3-x nanoflowers have been synthesized through a solvothermal/in-situ reduction two-step strategy, and they exhibit notable photoabsorption in a wide range (200–1100 nm), high photothermal conversion and efficient charge separation efficiency. Under simulated sunlight irradiation (0.3 W cm−2), Pd/WO3-x exhibits a maximum vanillin conversion up to 86.8 % with a 2-methoxy-4-methylphenol (MMP) selectivity of 100 %, which is obviously higher than that (vanillin conversion = 33.1 %, MMP selectivity = 100 %) in the oil bath at the same temperature. Such higher conversion efficiency and selectivity under sunlight should result from the synergistic integration of hot electrons and photothermal heating, both of which are derived from localized surface plasmon resonance (LSPR) in WO3-x. Importantly, Pd/WO3-x catalyst demonstrates good stability and high selectivity to MMP even after 5 cycles. This work may offer a novel viewpoint on the advancement of photothermal catalysts and the realization of photothermal catalytic biomass conversion under mild conditions.

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.

Construction of CdIn2S4/ZnSn(OH)6 heterojunctions for efficient photocatalytic hydrogen generation

CdIn2S4 nanosheets ornamented ZnSn(OH)6 microsquares (CIS/ZSOH) heterostructures were devised and fabricated using an easy hydrothermal procedure. The specimens were characterized exhaustively using diverse technologies and used to produce hydrogen. Compared with CdIn2S4 and ZnSn(OH)6, CIS/ZSOH heterostructures presented remarkably superior photocatalytic activities. In addition, CIS/ZSOH-35% exhibited the optimized hydrogen production amount of 4 mmol g−1. Also, the reusable constancy of CIS/ZSOH-35% was very prominent. From relevant characterization results, CIS/ZSOH-35% possessed bigger specific surface area, stronger light-absorption ability and higher charge separation efficiency, which would benefit to improve the photocatalytic performance. Ultimately, the formation of type II heterojunction by CdIn2S4 and ZnSn(OH)6 was confirmed by the band structure and UPS analyses. The study might administer a charming approach to modify the broad band gap photocatalysts.

Interfacial Si–O–Zr bonds induced well dispersed zirconia on magnetic mesoporous silicas for enhanced tetracycline removal

Constructing recoverable materials with both high adsorption capacity and excellent photocatalytic performance towards antibiotics elimination is very meaningful and challenging in wastewater remediation. In this work, we demonstrate a simple interface engineering strategy to design well dispersed zirconia on core–shell structured magnetic mesoporous silica microspheres (MMS) for efficient removal of tetracycline hydrochloride (TC). With ultrahigh specific surface area (682.0 m2/g) and interfacial Si-O-Zr serving as active sites, the optimal sample (MMS-Zr10) exhibits enhanced TC adsorption capacity of 266.5 mg/ZrO2 g, which is 19.2-fold than that of pure ZrO2. Simultaneously, the photocatalytic degradation rate constant of TC over MMS-Zr10 in the presence of peroxydisulfate (PDS) is 12.5 times that of ZrO2 under visible light irradiation, which may be attributed to the enhanced light harvest capability and high charge separation efficiency facilitated by interfacial Zr–O–Si charge transfer channels. Furthermore, in consecutive adsorption cycles in both deionized (DI) water solution and actual wastewater, no obvious decline in TC removal % is observed. The TC adsorption is mainly governed by pore filling, hydrogen bonding and electrostatic interactions; whilst O2•−, h+, SO4•−, •OH and 1O2 species are responsible for enhanced photocatalytic degradation of TC.