Modulating the Moderate d-Band Center of Indium in InVO4 Nanobelts by Synergizing MnOx and Oxygen Vacancies for High-Efficiency CO2 Photoreduction.

Modulating the electronic properties of transition metal sites in photocatalysts at the atomic level is essential for achieving high-activity carbon dioxide photoreduction (CO2PR). An electronic strategy is herein proposed to engineer In-d-band center of InVO4 by incorporating MnOx nanoparticles and oxygen vacancies (VO) into holey InVO4 nanobelts (MnOx/VO-InVO4), which synergistically modulates the In-d-band center to a moderate level and consequently leads to high-efficiency CO2PR. The MnOx/VO-InVO4 catalyst with optimized electronic property exhibits a single carbon evolution rate of up to 145.3 µmol g-1 h-1 and a carbon monoxide (CO) product selectivity of 92.6%, coming out in front of reported InVO4-based materials. It is discovered that the modulated electronic property favors the interaction between the In sites and their intermediates, which thereby improves the thermodynamics and kinetics of the CO2PR-to-CO reaction. This work not only demonstrates the effective engineering of the d orbital of the low-coordination In atoms to promote CO2PR, but also paves the way for the application of tuning d-band center to develop high-efficiency catalysts.

Fabrication of InVO4/SnWO4 heterostructured photocatalyst for efficient photocatalytic degradation of tetracycline under visible light.

In the present study, novel InVO4/SnWO4 nanocomposites with different concentrations of SnWO4 were successfully prepared using a facile hydrothermal technique and investigated employing a wide range of analytical methods for efficient photocatalytic degradation of tetracycline (TC). X-ray diffraction analysis showed the presence of the orthorhombic phases of both InVO4 and SnWO4 in the composite catalyst. Dispersion of SnWO4 nanoplates over the InVO4 nanosheets enhanced the synergistic interactions, improving the separation of charge carriers and their transfer. Furthermore, the formation of heterostructure expanded the absorption range and promoted visible light harvesting. The TC degradation efficiency of InVO4/SnWO4 nanocomposite (5 mg loading of SnWO4) reached 97.13% in 80 min under visible light, with the kinetic rate constants 5.51 and 7.63 times greater than those of pure InVO4 and SnWO4, respectively. Additionally, the scavenger results proved that hydroxyl radicals and holes played a significant role in the photodegradation of TC. Furthermore, the electrochemical impedance spectroscopy (EIS) and transient photocurrent response analysis showed enhanced e-/h+ partition efficiency. Thus, the formation of heterostructure with strong synergistic interactions can effectively transfer the excited charge carriers and shorten the reunion rate. Accordingly, the InVO4/SnWO4 nanocomposites exhibited remarkable photocatalytic performance due to the increased number of charge carriers on the surface.

InVO4-Decorated Ti3C2 MXene for Efficient Photocatalytic Hydrogen Evolution.

The generation of hydrogen through photocatalysis is a fascinating technology for addressing environmental concerns and the energy crisis. Nevertheless, the quest for cost-effective, stable, and efficient photocatalysts in the realm of energy conversion remains a significant challenge. Herein, we designed novel InVO4/Ti3C2 MXene (IVTC) heterostructures by employing acid etching to produce Ti3C2 MXene with an accordion-like morphology, using the hydrothermal technique for the production of orthorhombic InVO4 nanoparticles (NPs), and integrating them through a self-assembly approach. Both field-emission scanning electron microscopy and HRTEM analyses revealed a consistent distribution of InVO4 NPs with an average size of 43.4 nm on both surfaces and between the sheets of Ti3C2 MXene. The intimate interface between the Ti3C2 MXene nanosheet and InVO4 suppressed carrier recombination and promoted charge transfer, thereby boosting photocatalytic H2 production. Under visible light exposure, the rate of hydrogen evolution is enhanced in IVTC heterostructures containing an optimized 10% loading of InVO4, exhibiting over a 3-fold increase compared to pristine InVO4 NPs, maintaining efficiency across four cycles. This research presents a promising method for designing and creating high-efficiency heterostructures possessing excellent visible-light-driven photocatalytic activity for H2 evolution.

Formulating InVO4/α-Fe2O3 Heterojunction Composites for Photocatalytic Tetracycline Hydrochloride Degradation.

This study reports the synthesis of InVO4/α-Fe2O3 heterojunction photocatalysts with different stoichiometric ratios via a two-step hydrothermal synthesis reaction. The prepared photocatalysts were characterized by XRD, SEM, TEM, XPS, and other methods. The prepared composites exhibited good photocatalysis of tetracycline hydrochloride. Among the InVO4/α-Fe2O3 heterojunction photocatalysts with different ratios, the InVO4/0.25α-Fe2O3 photocatalyst showed the highest degradation rate for 20 mg L-1 tetracycline hydrochloride. After three photocatalytic runs, it still exhibited excellent stability and reusability. Meanwhile, this study also found that superoxide radical anion (-O2-), electron (e-), hydroxyl radical (·OH), and photogenerated hole (h+) are the basic active substances in the photocatalytic process.

Construction of dual Z-scheme Ag3VO4-BiVO4/InVO4 photocatalysts using vanadium source from spent catalysts for contaminated water treatment and bacterial inactivation.

Vanadate-based photocatalysts have recently attracted substantial attention owing to their outstanding photocatalytic activity for degrading organic pollutants and generating energy via photocatalytic processes. However, the relatively high price of vanadium has hindered the development of vanadate-based photocatalysts for various applications. Spent catalysts obtained from oil refineries typically contain a significant quantity of vanadium, making them valuable for recovery and utilization as precursors for the production of high-value-added photocatalysts. In this study, we transformed the V present in spent catalysts produced by the petrochemical industry into ternary vanadate-based photocatalysts [BiVO4/InVO4/Ag3VO4 (BVO/IVO/AVO, respectively)] designed for water remediation. The ternary composites revealed an enhanced photocatalytic capability, which was 1.42 and 5.1 times higher than those of the binary BVO/IVO and pristine AVO due to the facilitated charge separation. The ternary photocatalysts not only effectively treated wastewater containing various organic dyes, such as methylene blue (MB), rhodamine 6G (R6G), and brilliant green (BG), but also exhibited remarkable photocatalytic performance in the degradation of antibiotics, reduction of Cr(VI), and bacterial inactivation. This paper proposes a feasible route for recycling industrial waste as a source of vanadium to produce highly efficient vanadate-based photocatalysts.

Ultrasound assisted fabrication of InVO4/In2S3 heterostructure for enhanced sonophotocatalytic degradation of pesticides.

A cost effective and environmentally benign ultrasonic method has been developed for the synthesis of InVO4 (InV), In2S3 (InS) and the InVO4/In2S3 heterostructure (InV/InS). All the designed materials were evaluated for their structural, morphological, spectroscopic, and electrochemical characterizations. Materials were examined for photocatalytic, sonocatalytic, and sonophotocatalytic degradation of carbofuran (CBF) and diazinon (DZN) pesticides under visible light. InV/InS showed enhanced degradation of CBF and DZN when compared to InV and InS. Photocatalytic degradation was accelerated by ultrasonication and found to degrade 97 and 98 % of CBF and DZN in 60 and 70 min, respectively. The reaction conditions, like pH, catalyst dosage, acoustic intensity, and ultrasound power, were carefully optimized. Electron spin resonance (ESR) spectroscopy shows the generation of superoxide radical anion and hydroxyl radicals as reactive species during photoredox reaction. The CBF and DZN degradation intermediates were analyzed using liquid chromatography mass spectroscopy (LC-MS) that shows the mineralization of the CBF and DZN to CO2 and H2O. The effect of Cl-, and PO43- were examined towards degradation of CBF and DZN under optimal conditions in the presence of InV/InS. The degradation of CBF and DZN is decreased in presence of Cl-, CO32- and NO3- but PO43- ions does not show any effect on degradation. The bandgap and Mott-Schottky results suggest the existence of type-II heterostructure between InV and InS through the interface. The synthesis of heterostructure and degradation of pesticides utilizes ultrasonic waves, which prove their multiple applications and attract researchers towards the effective use of sonication.

Integration of high visible-light-driven ternary dual Z-scheme AgVO3-InVO4/g-C3N4 heterojunction nanocomposite for enhanced uranium(VI) photoreduction separation.

With deepening application of nuclear power technology, the problem of water ecological environment pollution caused by uranium (U(VI)) is becoming increasingly serious. Photoreduction separation of U(VI) on photocatalysts is considered as an effective strategy to solve uranium pollution. In this work, a novel ternary dual Z-scheme AgVO3-InVO4/g-C3N4 heterojunction (Z-AIGH) nanocomposite with high surface area (73.45 m2 g-1, Z-AIGH2) was designed. The batch adsorption experiment in dark environment showed that Z-AIGH2 nanocomposite had an excellent U(VI) adsorption performance. As for photocatalytic experiments, Z-AIGH2 exhibited a rapid photocatalytic response for separating U(VI) without any organic sacrifice agents. The U(VI) separation rate on Z-AIGH2 nanocomposite was over 98.7% after only 20.0 min visible light irradiation (T = 298 K, CU(Ⅵ) = 10.0 mg L-1, m/V = 0.1 g L-1 and pH = 7.0). Z-AIGH2 nanocomposite also showed good selectivity and cycle stability. The U(VI) removal rate of Z-AIGH2 nanocomposite after fifth cycles was about 96.1% (T = 298 K, CU(Ⅵ) = 10.0 mg L-1, m/V = 0.1 g L-1 and pH = 7.0). High photocatalytic activity of Z-AIGH2 for U(VI) was attributed to the construction of ternary dual Z-scheme heterojunction structure and ant nest-like hole structure. Based on above results, Z-AIGH2 nanocomposite had great potential for water environment renovation.

Z-scheme CoAl-layereddoublehydroxide/indium vanadate heterojunction for enhanced and highly selective photocatalytic reduction of carbon dioxide to carbon monoxide.

Development of efficient photocatalysts is essential for carbon dioxide (CO2) photocatalytic reduction. In this study, Z-scheme CoAl-layered double hydroxide (LDH)/indium vanadate (InVO4) heterojunction photocatalysts were synthesized using hydrothermal method, and their performance toward CO2 reduction and mechanism were determined. Results of characterizations showed that the CoAl-LDH/InVO4-30 exhibited desired morphology, the most efficient photogenerated carriers separation and charge transfer, and the highest photocurrent response. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) manifested that charge transfer of the CoAl-LDH/InVO4 conformed to Z-scheme mechanism. The CoAl-LDH/InVO4-30 exhibited the highest carbon monoxide (CO) yield of 174.4 µmol g-1 within 2 h of reaction, which was 2.46 and 9.79 times of pure CoAl-LDH and InVO4, respectively. The CO selectivity was up to nearly 100%. Moreover, in-situ fourier transform infrared spectroscopy (ISFT-IR) demonstrated that bicarbonate (HCO3*) and carboxylate (COOH*) were the main intermediates during the CO2 reduction process, and possible CO2 reduction pathways were proposed. This work provides a reference for construction of Z-scheme LDH-based heterojunctions for efficient CO2 photoreduction.

CdS-based artificial leaf for photocatalytic hydrogen evolution and simultaneous degradation of biological wastewater.

Rational design of all-solid-state Z-scheme heterojunction with advanced structure is essential for boosting photocatalytic efficiency. Herein, we design and fabricate a novel Z-scheme photocatalyst with leaf architecture (named artificial leaf) via a simple dipping-calcination (DC) process followed by a successive ionic layer adsorption and reaction (SILAR) strategy. The prepared artificial leaf, composing of CdS, InVO4, and BiVO4, holds advanced leaf-like structure and Z-scheme electron transfer pathway. As a result, this novel artificial leaf exhibits outstanding capability for the harvesting of visible light and superior efficiency for the separation of photogenerated electron-hole pairs, as well as remarkably enhanced photocatalytic performance and stability for H2 evolution (with the rate of 5033 µm g-1∙h-1) and pollution degradation (46% pollution can be degraded within 3 h).

Facile Assembly of InVO4/TiO2 Heterojunction for Enhanced Photo-Oxidation of Benzyl Alcohol.

In this work, an InVO4/TiO2 heterojunction composite catalyst was successfully synthesized through a facile hydrothermal method. The structural and optical characteristics of InVO4/TiO2 heterojunction composites are investigated using a variety of techniques, including powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and spectroscopy techniques. The addition of InVO4 to TiO2 considerably enhanced the photocatalytic performance in selective photo-oxidation of benzyl alcohol (BA). The 10 wt% InVO4/TiO2 composite photocatalyst provided a decent 100% BA conversion with over 99% selectivity for benzaldehyde, and exhibited a maximum conversion rate of 3.03 mmol g-1 h-1, which is substantially higher than bare InVO4 and TiO2. The excellent catalytic activity of the InVO4/TiO2 photocatalyst is associated with the successful assembly of heterostructures, which promotes the charge separation and transfer between InVO4 and TiO2.

Facile synthesizing Z-scheme Bi12O15Cl6/InVO4 heterojunction to effectively degrade pollutants and antibacterial under light-emitting diode light.

The design of a photocatalytic system with Z-scheme heterojunction is the key to charge separation. In this paper, a simple synthesis method was used to prepare Bi12O15Cl6/InVO4 photocatalyst. The synthesized photocatalyst can effectively degrade pollutants, and inactivate bacteria under LED light irradiation. The optimal ratio of 30% Bi12O15Cl6/InVO4 material effectively degraded 78.85% of TC and 97.83% of RhB within 90 min and inactivated Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in 40 min. This improvement in photocatalytic performance is mainly due to the formation of a Z-scheme heterojunction between Bi12O15Cl6 and InVO4, which produces effective charge separation and improves photocatalytic degradation and antibacterial activity. The capture experiment revealed the main active substances. The effects of catalyst dosage and pollutant concentration were investigated in details. The intermediates of TC degradation were identified by mass spectrometry (MS), and the possible photocatalytic degradation pathway was proposed. Capture experiment and related measurements proposed the Z-scheme mechanism. This work emphasizes the importance of heterogeneous structure construction and proposes feasible solutions for the rational design of catalysts with photodegradation and antibacterial properties under LED light.

Ultrathin indium vanadate/cadmium selenide-amine step-scheme heterojunction with interfacial chemical bonding for promotion of visible-light-driven carbon dioxide reduction.

The formation of interfacial chemical bonding in heterostructures plays an important role in the transport of carriers. Herein, we firstly prepared ultrathin InVO4 nanosheet (Ns) with a thickness of 1.5 nm. Diethylenetriamine-modified CdSe (CdSe-DETA) nanobelts are in-situ deposited on the surface of ultrathin InVO4 Ns to build a InVO4/CdSe-DETA step-scheme (S-scheme) heterojunction photocatalysts. The protonated DETA acts as an amine-bridge to promote the formation of a tight chemical bond at the interface of InVO4/CdSe-DETA, thereby promoting the transfer of carriers at the interface. For photocatalytic CO2 reduction, the rationally designed InVO4/CdSe-DETA S-scheme photocatalyst exhibits a remarkable CO generation rate of 27.9 µmol h-1 g-1 at 420 nm, which is 3.35 and 3.39 times higher than that of CdSe-DETA and InVO4 Ns, respectively. The new method by using interfacial chemical bonding to facilitate interfacial charge transportation provide a promising strategy for improve photocatalysis.

Hollow InVO4 Nanocuboid Assemblies toward Promoting Photocatalytic N2 Conversion Performance.

The unique InVO4 mesocrystal superstructure, particularly with cubical skeleton and hollow interior, which consists of numerous nanocube building blocks, closely stacking by stacking, aligning by aligning, and sharing the same crystallographic orientations, is successfully fabricated. The synergy of a reaction-limited aggregation and an Ostwald ripening process is reasonably proposed for the growth of this unique superstructure. Both single-particle surface photovoltage and confocal fluorescence spectroscopy measurements demonstrate that the long-range ordered mesocrystal superstructures can significantly retard the recombination of electron-hole pairs through the creation of a new pathway for anisotropic electron flow along the inter-nanocubes. This promising charge mobility feature of the superstructure greatly contributes to the pronounced photocatalytic performance of the InVO4 mesocrystal toward fixation of N2 into NH3 with the quantum yield of 0.50% at wavelength of 385 nm.

Fabrication of Hierarchical Indium Vanadate Materials for Supercapacitor Application.

Transition metal orthovanadates are emerging 2D materials for promising electrochemical energy storage applications. Facile hydrothermal method for nanocrystalline indium vanadate (InVO4) semiconducting materials' fabrication is economical because of its direct chemical synthesis. X-ray diffraction studies, field emission scanning electron microscope (SEM) images, transmission electron microscopy (TEM), and photoelectron X-ray spectrum are used to describe the semiconductor materials as synthesized. InVO4 microspheres have attracted a lot of attention in the energy and environmental sector. These microsphere-derived semiconductor materials are recognized to offer the advantages of their large surface area, tunable pore sizes, enhanced light absorption, efficient carrier (electron-hole) separation, superior electronic and optical behavior, and high durability. From the results of SEM and TEM, InVO4 shows a microsphere construction with a mixture of nanosized particles. Diffuse reflectance UV-visible measurements are used to determine the bandgap, and it is found to be 2.1 eV for InVO4. The electrochemical analysis reveals a superior performance of the pseudocapacitor with hydrothermally derived microspheres of InVO4. Alongside an improved pseudocapacity, developed after 4000 cycles, it has excellent cycling stability with a retention of ≈94% of its original specific capacitance efficiency.

Fabrication of the novel Ag-doped SnS2@InVO4 composite with high adsorption-photocatalysis for the removal of uranium (VI).

A novel Ag-doped SnS2@InVO4 composite was successfully synthesized for efficient uranium removal from wastewater through a facile hydrothermal method. The structure, morphology and optical property of materials were characterized using various instruments. The results proved that Ag-doped SnS2@InVO4 composite presented as hexangular nanosheets with about 4.87 nm pore size and 101.58 m2/g specific surface area. Further characterization demonstrated that photo-adsorption ability of visible light was enhanced and band gap was narrowed. The adsorption kinetics and isotherm of U(VI) on Ag-doped SnS2@InVO4 composite could be depicted via the Langmuir model and pseudo-second-order mode, and the maximum adsorption capacity of U(VI) reached 167.79 mg/g. The elimination of U(VI) of as-synthesized composites was studied by a synergy of adsorption and visible-light photocatalysis, and the optimal content of InVO4 was found to be 2 wt% with the highest removal efficiency of 97.6%. In addition, compared with pure SnS2 and Ag-doped SnS2, the Ag-doped SnS2@InVO4 composites exhibited superior photocatalytic performance for the conversion of soluble U(VI) to insoluble U(IV) under visible light. The excellent photocatalytic performance was mainly attributed to numerous surface-active sites, strong optical adsorption ability and narrow band gap. Simultaneously, the heterojunction between Ag-doped SnS2 and InVO4 promoted the separation and transfer of photoexcited charges. The cyclic experiments indicated the Ag-doped SnS2@InVO4 composite remained good structural stability and reusability. Finally, the possible mechanism was discussed based on the experimental analysis.

Enhancement in the photocatalytic antifouling efficiency over cherimoya-like InVO4/BiVO4 with a new vanadium source.

The problem of marine life attachment and its pollution to facilities has caused a lot of great troubles in the development and application of marine resources. The holes generated by the photocatalytic coating materials under sunlight may produce strong oxidizing species and showed a significant effect on the degradation and bactericidal performance of environmental organic matter. In this paper, a novel bismuth vanadate/indium vanadate (BiVO4/InVO4) composite with cherimoya-like microstructure was fabricated using new vanadium source. It is found that the composite materials showed enhanced photocatalytic antifouling property. The degradation efficiency of the model pollutes (Rhodamine B, RhB) achieved 99.775% within 280 min over BiVO4/InVO4 nanostructures, and the sterilization rate of E. coli, S. aureus, P. aeruginosa and A. carterae achieved 99.7148%, 99.5519%, 99.5411% and 96.00%, respectively. Moreover, the circulate photocatalytic degradation of antibacteria experiments demonstrated the outstanding stability and reusability of BiVO4/InVO4 composite. According to the active free radical trapping experiments, the hydroxyl radical (OH) and superoxide radical (O2-) were certified to be the main reactive oxygen species in the BiVO4/InVO4 system. The distinctly enhanced photocatalytic performance of BiVO4/InVO4 nanomaterial primarily resulted from the narrow bandgap (about 1.86 eV). This study not only provides a new method for developing novel antibacterial materials, but also introduces a visible light-driven photocatalyst for water treatment and marine antifouling, especially for red tide control.

Hydrothermal Synthesis g-C3N4/Nano-InVO4 Nanocomposites and Enhanced Photocatalytic Activity for Hydrogen Production under Visible Light Irradiation.

We synthesized g-C3N4/nano-InVO4 heterojunction-type photocatalyts by in situ growth of InVO4 nanoparticles onto the surface of g-C3N4 sheets via a hydrothermal process. The results of SEM and TEM showed that the obtained InVO4 nanoparticles 20 nm in size dispersed uniformly on the surface of g-C3N4 sheets, which revealed that g-C3N4 sheets was probably a promising support for in situ growth of nanosize materials. The achieved intimate interface promoted the charge transfer and inhibited the recombination rate of photogenerated electron-hole pairs, which significantly improved the photocatalytic activity. A possible growth process of g-C3N4/nano-InVO4 nanocomposites was proposed based on different mass fraction of g-C3N4 content. The obtained g-C3N4/nano-InVO4 nanocomposites could achieve effective separation of charge-hole pairs and stronger reducing power, which caused enhanced H2 evolution from water-splitting compared with bare g-C3N4 sheets and g-C3N4/micro-InVO4 composites, respectively. As a result, the g-C3N4/nano-InVO4 nanocomposite with a mass ratio of 80:20 possessed the maximum photocatalytic activity for hydrogen production under visible-light irradiation.

Synergistic photocatalysis for bacteria inactivation and organic pollutant removal by S-scheme heterojunction InVO4/Bi5O7I: Performance evaluation and mechanism investigation.

The low efficiency of charge carrier separation is a major limitation hindering the application of photocatalytic technology. Constructing S-scheme heterojunction photocatalysts not only effectively promotes the separation of charge carriers, but also maximizes the oxidative and reductive capabilities of the two monomers. In this study S-scheme heterogeneous InVO4/Bi5O7I photocatalyst was synthesized by hydrothermal method combined with calcination. The optimal sample 20 % InVO4/Bi5O7I can completely deactivate Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in 30 min, remove 20 mg/L TC 76.0 % in 60 min and 20 mg/L BPA 93.0 % in 90 min. Intermediate products of TC and BPA degradation were detected using LC-MS, and possible degradation pathways were proposed. The photocurrent and electrochemical impedance spectroscopy (EIS) tests confirm that InVO4/Bi5O7I exhibits excellent photocurrent intensity and photocarrier migration ability, which are crucial reasons for the enhancement of the photocatalytic performance of the InVO4/Bi5O7I composite. Capture experiments indicate that OH, O2-, h+ and e-are reactive species. EPR further confirms the generation of OH and O2-. Combined with Kelvin probe force microscopy (KPFM) and band structure analysis, it is proposed that InVO4/Bi5O7I has an S-scheme charge transfer mechanism.