Bi2MoO6 Research Articles

Bimetal PtPd functionalized Bi2MoO6 microspheres for conductometric detection of CO: A combined experimental and theoretical study

The bimetallic nanoparticles modified polymetallic oxides are considered to be an attractive method to improve sensing performance. In this study, Bi2MoO6 (BMO) microspheres with bimetallic PtPd modification were synthesized via facile ultrasonic reduction and further solvothermal methods. The samples were characterized by SEM, HRTEM, XPS and UV–vis methods. The results showed the sensor based on BMO-1.5% exhibited an excellent response value of 7.18–200 ppm carbon monoxide (CO), which was approximately 5.28-fold higher than that of the initial BMO sensor (1.36). It also exhibited rapid response/recovery time (12/12 s). The theoretical calculation results exhibited the adsorption energy of PtPd/BMO (−2.29 eV) for CO molecules was substantially lower than that of the initial BMO (−0.05 eV). Total and partial density of states was determined to investigate the interaction between PtPd and BMO. The significantly enhanced gas properties of BMO-based sensors were attributed to the strong metal-support interaction (SMSI) and the sensitization of Pt and Pd. The work provides a feasible strategy for the analysis of sensing mechanisms.

Citric acid-assisted in-situ synthesis of a distinctive 3D flower-like spherical Bi2MoO6 nano-film and its enhanced CO2 photoreduction activity

The photocatalytic CO2 reduction reaction for producing chemical fuels is an ideal advanced technology to effectively mitigate global warming and the energy crisis. Importantly, how to achieve excellent activity and cyclic utilization of photocatalysts has been one research hot-topic. In this work, a Bi2MoO6 (BMO) nano-film with a 3D flower-like spherical structure was fabricated on a Bi plate via a room-temperature in-situ electrochemical ion-exchange method with the assistance of citric acid (CA) (BMO (+CA)). The experimental results show that the BiOBr nano-film, as sacrificial template, plays an important role in the synthesis of the BMO nano-film. The BMO (+CA) nano-film exhibits superior photocatalytic CO2 reduction activity with a CO yield (258μmol g−1), under simulated sunlight irradiation, 3.6 times higher than the BMO (-CA) nano-film with a nanosheet-like structure. Moreover, the dominating reason and action mechanism of the enhanced photocatalytic CO2 reduction performance for the BMO (+CA) nano-film are proposed. Our outcomes provide new insights into the development and research of highly-efficient Bi-based nano-films in the CO2 reduction reaction field.

Mannitol and acidity co-tuned synthesis of oxygen-vacancy-modified bismuth molybdate nanorods for efficient photocatalytic nitrogen reduction to ammonia

Oxygen vacancies (Ovs) in semiconductors, which can adsorb and activate N2 molecules, are active sites for photocatalytic nitrogen reduction to ammonia. However, simple and effective methods for creating Ovs still need to be explored. Herein, mannitol was used to selectively create Ovs at Mo in Bi2MoO6 (BMO) and form BMO short nanorods (SNRs) through a hydrothermal process, with the Ov content, SNR size, and surface area of the sample effectively tuned by pH. BMO SNRs containing the most Ovs exhibit the highest visible light absorption, fastest photoexcited charge separation, and best photocatalytic nitrogen fixation performance, with an N2 reduction reaction rate in pure water reaching approximately 107-fold that of BMO nanosheets synthesized in the absence of mannitol, and an apparent quantum yield of 2.78% at 420 nm, superior to all of the reported BMO-based photocatalysts. This work provides a new and simple method for selective Ov creation and the morphological tuning of BMO to expedite the photocatalytic N2 reduction.

Flexible Bi2MoO6/S-C3N4/PAN heterojunction nanofibers made from electrospinning and solvothermal route for boosting visible-light photocatalytic performance

This work elaborated the synthesis and characterization of flexible Bi2MoO6/S-C3N4/ PAN composite fabricated by the electrospinning of the mixture of S-doped g-C3N4 (SCN) and PAN, which resulted in the formation of 1D SCN/PAN nanofibers (NFs) followed by the deposition of the 2D Bi2MoO6 (BMO) nanosheets on their surfaces via a solvothermal route. Among the synthesized NFs, 12 %SCN/PAN NFs made using the SCN/PAN ratio of 12 showed the highest photocatalytic activity for degrading 4-nitrophenol (4-NP), i.e., 83 % 4-NP degraded within 180 min. Further deposition of BMO onto 12 %SCN/PAN, represented by BMO-2/12 %SCN/PAN NFs sample, led to significant improvement in 4-NP photocatalytic degradation performance, enabling 94 % 4-NP to be degraded within 90 min. Such excellent performance can be ascribed to the synergetic effects of the unique hierarchical core–shell and S-scheme heterojunction properties. They could enhance the separation of electron-hole pairs and reserve redox capabilities, where h+ and ·O2– radicals were their main reactive species responsible for the photodegradation. Moreover, BMO-2/12 %SCN/PAN NFs can be efficiently reused due to their flexible nanofibrous mat-like structure. This work provides new insights into developing self-supporting photocatalysts for removing organic pollutants.

Synergy-Compensation Effect of Ferroelectric Polarization and Cationic Vacancy Collaboratively Promoting CO2 Photoreduction.

Photocatalytic CO2 reduction is severely limited by the rapid recombination of photo-generated charges and insufficient reactive sites. Creating electric field and defects are effective strategies to inhibit charge recombination and enrich catalytic sites, respectively. Herein, a coupled strategy of ferroelectric poling and cationic vacancy is developed to achieve high-performance CO2 photoreduction on ferroelectric Bi2 MoO6 , and their interesting synergy-compensation relationship is first disclosed. Corona poling increases the remnant polarization of Bi2 MoO6 to enhance the intrinsic electric field for promoting charge separation, while it decreases the CO2 adsorption. The introduced Mo vacancy (VMo ) facilitates the adsorption and activation of CO2 , and surface charge separation by creating local electric field. Unfortunately, VMo largely reduces the remnant polarization intensity. Coupling poling and VMo not only integrate their advantages, resulting in an approximately sevenfold increased surface charge transfer efficiency, but also compensate for their shortcomings, for example, VMo largely alleviates the negative effects of ferroelectric poling on CO2 adsorption. In the absence of co-catalyst or sacrificial agent, the poled Bi2 MoO6 with VMo exhibits a superior CO2 -to-CO evolution rate of 19.75µmol g-1 h-1 , ≈8.4 times higher than the Bi2 MoO6 nanosheets. This work provides new ideas for exploring the role of polarization and defects in photocatalysis.

Facet-specific Active Surface Regulation of Bix MOy (M=Mo, V, W) Nanosheets for Boosted Photocatalytic CO2 reduction.

Photocatalytic performance can be optimized via introduction of reactive sites. However, it is practically difficult to engineer these on specific photocatalyst surfaces, because of limited understanding of atomic-level structure-activity. Here we report a facile sonication-assisted chemical reduction for specific facets regulation via oxygen deprivation on Bi-based photocatalysts. The modified Bi2 MoO6 nanosheets exhibit 61.5 and 12.4 μmol g-1 for CO and CH4 production respectively, ≈3 times greater than for pristine catalyst, together with excellent stability/reproducibility of ≈20 h. By combining advanced characterizations and simulation, we confirm the reaction mechanism on surface-regulated photocatalysts, namely, induced defects on highly-active surface accelerate charge separation/transfer and lower the energy barrier for surface CO2 adsorption/activation/reduction. Promisingly, this method appears generalizable to a wider range of materials.

CTAB-assisted synthesis of Bi2MoO6 hierarchical microsphere and its application as a novel efficient and recyclable adsorbent in removing organic pollutants

Herein we have synthesized Bi2MoO6 (BMO) hierarchical microspheres via a solvothermal method using hexadecyl trimethyl ammonium bromide (CTAB) as surfactant, and demonstrated that the synthesized BMO can be used as an efficient and recyclable adsorbent for removing organic pollutants. By using methylene blue (MB) as the target pollutant, the adsorption kinetics, adsorption isotherms and adsorption thermodynamics of MB onto the BMO adsorbent were systematically investigated. The effects of pH, temperature and adsorbent dosage on the MB adsorption by BMO were predicted by response surface methodology (RSM) with Box-Behnken design (BBD). It is interestingly demonstrated that the BMO adsorbent can be easily regenerated via a simple calcination process in air and exhibits excellent reusability. To promote the practical application of the BMO adsorbent in water purification, we have further compared its adsorption capability in removing 18 kinds of organic pollutants (including various organic dyes, antibiotics and other serious organic pollutants) at different acidic-alkaline environments. In the normal and alkaline (pH 12) environments, the highest adsorption is observed for Congo red (CR) with qe = 216.331 and 232.723 mg g−1, respectively; whereas in the acidic environment (pH 2), the highest adsorption is observed for eriochrome black T (EBT) with qe = 64.362 mg g−1. Based on the experimental results, the involved adsorption mechanism was analyzed.

Tuning reactivity of Bi2MoO6 nanosheets sensors toward NH3 via Ag doping and nanoparticle modification

Noble metal-doping and modification are proved effective in improving the gas-response performance of semiconductor sensors. In this study, we developed a promising Bi2MoO6 (BMO)-based gas sensor capable of sensing ppb-level NH3 at room temperature via introducing silver (Ag). The BMO samples with different Ag doping and modification ratios were successfully formed via one-step solvothermal and glucose reduction techniques, respectively, which could be confirmed by the results of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) techniques. Compared to bare BMO, the gas-sensing properties of both Ag-doped and Ag surface-modified BMO samples were improved to various extents, respectively. In particular, the 5% Ag-modified BMO sensor with the highest response (Gg/Ga = 37.6 to 200 ppb NH3), long-term stability, and low threshold concentration (50 ppb) at 20% RH. Based on the spillover effect and metal–semiconductor junctions of Ag nanoparticles, the enhanced sensing response towards NH3 can be thoroughly illustrated. Combined with the first-principles calculations, the adsorption energy, density of states, and charge transfer of Ag-modified BMO were further performed to demonstrate the high sensing response and ultra-low detection limit.

High-efficient mineralization of formaldehyde by three-dimensional “PIZZA”-like bismuth molybdate-titania/diatomite composite

The application of TiO2-based photocatalysts in air pollution control has attracted much attention thanks to their advantageous green and sustainable performance. However, how to improve the degradation efficiency under visible light is still challenging. Herein, we report a ternary three-dimensional “PIZZA”-like Bi2MoO6-TiO2/diatomite (BTD) composite with high-efficient mineralization and recycling performance towards gaseous formaldehyde (HCHO) under visible light. The high-efficient adsorption-photocatalysis collaborative system with intimate interface combination is successfully established among Bi2MoO6 (BMO), TiO2 and diatomite. The HCHO mineralization rate constant of BTD-1:2 composite is up to around 4.03 times and 2.18 times higher than those of bare BMO and binary Bi2MoO6-TiO2 composite, respectively. It is indicated that the introduction of diatomite increases active sites and plays the vital role in the improvement of photocatalysis. In addition, the photogenerated holes (h+) and hydroxyl radical (OH) are proved to be the main active species for HCHO mineralization. Furthermore, there is a competitive adsorption relationship between water (H2O) molecules and HCHO molecules, and both H2O molecules and oxygen (O2) molecules participated in the reaction of HCHO mineralization based on in-situ DRIFTs spectra analysis. Our work would give a new perspective on gaseous HCHO purification.

Ni(NH3)62+ more efficient than Ni(H2O)62+ and Ni(OH)2 for catalyzing water and phenol oxidation on illuminated Bi2MoO6 with visible light

Nickel (hydr)oxide (NiOH) is known to be good co-catalyst for the photoelectrochemical oxidation of water, and for the photocatalytic oxidation of organics on different semiconductors. Herein we report a greatly improved activity of Bi2MoO6 (BMO) by nickel hexammine perchlorate (NiNH). Under visible light, phenol oxidation on BMO was slow. After NiNH, NiOH, and Ni2+ loading, a maximum rate of phenol oxidation increased by factors of approximately 16, 8.8, and 4.7, respectively. With a BMO electrode, all catalysts inhibited O2 reduction, enhanced water (photo-)oxidation, and facilitated the charge transfer at solid-liquid interface, respectively, the degree of which was always NiNH > NiOH > Ni2+. Solid emission spectra indicated that all catalysts improved the charge separation of BMO, the degree of which also varied as NiNH > NiOH > Ni2+. Furthermore, after a phenol-free aqueous suspension of NiNH/BMO was irradiated, there was a considerable Ni(III) species, but a negligible NH2 radical. Accordingly, a plausible mechanism is proposed, involving the hole oxidation of Ni(II) into Ni(IV), which is reactive to phenol oxidation, and hence promotes O2 reduction. Because NH3 is a stronger ligand than H2O, the Ni(II) oxidation is easier for Ni(NH3)6+ than for Ni(H2O)6+. This work shows a simple route how to improve BMO photocatalysis through a co-catalyst.

Aurivillius Oxides Nanosheets-Based Photocatalysts for Efficient Oxidation of Malachite Green Dye.

Aurivillius oxides ferroelectric layered materials are formed by bismuth oxide and pseu-do-perovskite layers. They have a good ionic conductivity, which is beneficial for various photo-catalyzed reactions. Here, we synthesized ultra-thin nanosheets of two different Aurivillius oxides, Bi2WO6 (BWO) and Bi2MoO6 (BMO), by using a hard-template process. All materials were characterized through XRD, TEM, FTIR, TGA/DSC, DLS/ELS, DRS, UV-Vis. Band gap material (Eg) and potential of the valence band (EVB) were calculated for BWO and BMO. In contrast to previous reports on the use of multi composite materials, a new procedure for photocatalytic efficient BMO nanosheets was developed. The procedure, with an additional step only, avoids the use of composite materials, improves crystal structure, and strongly reduces impurities. BWO and BMO were used as photocatalysts for the degradation of the water pollutant dye malachite green (MG). MG removal kinetics was fitted with Langmuir—Hinshelwood model obtaining a kinetic constant k = 7.81 × 10−2 min−1 for BWO and k = 9.27 × 10−2 min−1 for BMO. Photocatalytic dye degradation was highly effective, reaching 89% and 91% MG removal for BWO and BMO, respectively. A control experiment, carried out in the absence of light, allowed to quantify the contribution of adsorption to MG removal process. Adsorption contributed to MG removal by a 51% for BWO and only by a 19% for BMO, suggesting a different degradation mechanism for the two photocatalysts. The advanced MG degradation process due to BMO is likely caused by the high crystallinity of the material synthetized with the new procedure. Reuse tests demonstrated that both photocatalysts are highly active and stable reaching a MG removal up to 95% at the 10th reaction cycle. These results demonstrate that BMO nanosheets, synthesized with an easy additional step, achieved the best degradation performance, and can be successfully used for environmental remediation applications.

Bismuth molybdate photocatalyst for the efficient photocatalytic degradation of tetracycline in water under visible-light irradiation

Based on a solvothermal method using Bi2MoO6 (BMO) as the raw material, a novel BiOCl BMO photocatalyst with a flower-like spherical structure was synthesized. The photocatalytic activity of this catalyst was evaluated using a Xe lamp (λ ≥ 420 nm) to simulate sunlight. The crystal structure, morphology, and photochemical characteristics of the BiOCl–BMO photocatalyst were characterized by X-ray diffractometry, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, Raman spectroscopy, photoluminescence measurements, and electrochemical impedance spectroscopy. Under visible-light irradiation, 50 mg BiOCl–BMO with a BiOCl/BMO mass rate of 0.06 degraded 97.23% of a tetracycline (TC) hydrochloride solution (50 mL, 10 mg/L) within 100 min, with a mineralization rate of 81.22%. Free-radical capture experiment revealed that the •OH, •O2−, h+, and e− species (and in particular •OH and •O2−) promoted TC degradation. Furthermore, the active free radicals and TC photodegradation intermediates were identified, and the mechanism and degradation pathways of TC photodegradation by the heterojunction structures were proposed. This study describes an efficient catalyst for the removal of TC from water and introduces a new approach that could be applied in the design of other Bi-based photocatalysts with excellent photocatalytic properties. At the same time, the developed system is of great significance for the efficient removal of TC from aqueous environments.

An in-situ generated Bi-based sodiophilic substrate with high structural stability for high-performance sodium metal batteries

Sodium (Na) metal anode exhibits a potential candidate in next-generation rechargeable batteries owing to its advantages of high earth abundance and low cost. Unfortunately, the practical development of sodium metal batteries is inherently plagued by challenges such as the side reactions and the growth of Na dendrites. Herein we report a highly stable Bi-based “sodiophilic” substrate to stabilize Na anode, which is created by in-situ electrochemical reactions of 3D hierarchical porous Bi2MoO6 (BMO) microspheres. BMO is initially transformed into the Bi “nanoseeds” embedded in the Na-Mo-O matrix. Subsequently, the Bi nanoseeds working as preferential nucleation sites through the formation of Bi-Na alloy enable the non-dendritic Na deposition. The asymmetric cells based on such BMO-based substrate can deliver a long-term cycling for 600 cycles at a large capacity of 4 mAh cm−2and for 800 cycles at a high current density of 10 mA cm−2. Even at a high depth of discharge (66.67%), the Na-predeposited BMO (Na@BMO) electrodes can cycle for more than 1600 h. The limited Na@BMO anodes coupled with the Na3V2(PO4)3 cathodes (N/P ratio of 3) in full cells also show excellent electrochemical performance with a capacity retention of about 97.4% after 1100 cycles at 2 C.

Rationally designed tetra (4-carboxyphenyl) porphyrin/graphene quantum dots/bismuth molybdate Z-scheme heterojunction for tetracycline degradation and Cr(VI) reduction: Performance, mechanism, intermediate toxicity appraisement

Constructing novel Z-scheme heterojunctions is an effective strategy for obtaining high-performance photocatalysts. Herein, tetra (4-carboxyphenyl) porphyrin (TCPP) and graphene quantum dots (GQDs) were loaded on the surface of Bi2MoO6 (BMO) to fabricate novel Z-scheme heterojunctions of TCPP/G/BMO. Especially, TCPP/G/BMO-2 showed an exceptional visible-light photoactivity for tetracycline (TC) degradation (81.0%, 40 min) and Cr(VI) reduction (90.7%, 60 min), respectively by 2.38 folds and 2.96 folds enhancement compared to sole Bi2MoO6. The substantial enhancement of activity is attributed to the synergy effect of the Z-scheme charge transfer mechanism and the improved light absorption. The degradation pathways of TC were inferred by determining the generated intermediates using high performance liquid chromatography-mass spectrometry (HPLC-MS), and the toxicity of the transformation products was assessed by Toxicity Estimation Software Tool (T.E.S.T). Overall, on the basis of trapping experiments and electron spin resonance spectra (ESR) analysis, the photocatalytic mechanisms of Cr(VI) reduction and TC degradation by the TCPP/G/BMO Z-scheme heterojunction was proposed. This work indicates TCPP/G/BMO could be a promising photocatalyst for wastewater treatment.

Valence-mixed iron phthalocyanines/(1 0 0) Bi2MoO6 nanosheet Z-scheme heterojunction catalysts for efficient visible-light degradation of 2-chlorophenol via preferential dechlorination

It is vital for selectively preferential dechlorination by visible-light photocatalysis to eliminate high-risk 2-chlorophenol (2-CP) contaminant. However, selective adsorption and efficient charge separation remain challenging. Herein, ultrathin (100) facet-exposed Bi2MoO6 (BMO) nanosheets (∼6 nm thickness) with enhanced selective adsorption for 2-CP due to the Bi-Cl interaction and highly visible-light activity for 2-CP degradation have been synthesized via a pH-controlled microwave-assisted hydrothermal process. The visible-light activity could be improved by modifying iron phthalocyanines (FePc) via H-bond induced assembly and subsequent H2 thermal treatment. The visible-light activity of as-optimized H2-treated heterojunction (H-FePc/BMO) was 4.5 and 2.5-time higher than BMO and FePc/BMO. Raman spectra, X-ray photoelectron spectrum, electron paramagnetic resonance, photoelectrochemical measurements, radical trapping experiment and ion chromatography, confirmed that the improved photoactivity of H-FePc/BMO could be attributed to the selective adsorption of 2-CP inducing photogenerated-holes as dominating active species with nearly 100% preferential dechlorination, the enhanced charge separation via Z-scheme transfer and the promoted O2 activation from valence-mixed Fe0/Fe2+ species in FePc after H2 treatment. This study may open up a new way to the high-efficiency degradation of chlorophenols using bismuth-containing oxide-based photocatalysts.

A facile solvothermal syntheses of NiFe layered double hydroxide-Bi2MoO6 heterostructure/reduced graphene oxide with efficient photodegradation for tetracycline.

A heterojunction of NiFe layered double hydroxide (NiFe LDH)-Bi2MoO6 (BMO) loaded on reduced graphene oxide (RGO) sheets was synthesized via an eco-friendly solvothermal reaction. The structural characterization shows that NiFe LDH-BMO heterojunctions are well-distributed on the surface of silk-like transparent RGO sheets. The modification of BMO by NiFe LDH and RGO greatly enhances the photocatalytic performance of BMO for degradation of tetracycline (TC) under visible light. The photocatalyst prepared with 3wt% RGO shows the highest activity and cycle stability. TC can be completely removed in 80min, which is about 8.7 times that pure BMO, and showing excellent reusability even after five cycles. The excellent enhancement of photocatalytic performance of NiFe LDH-BMO/RGO composite is attributed to the unique sheet-on-sheet hierarchical heterostructure combined with RGO sheets, facilitating the visible light absorption and photogenerated charge carriers separation.

Bi2MoO6 and Ag nanoparticles immobilized on textile by plasma-derived innovative techniques to generate antimicrobial activity

In this study, we expose various techniques based on cold plasma discharge (CPD), and more precisely aqueous-phase plasma-aided grafting (APPAG), to efficiently modify the surface of polymers as well as fabric made of natural fibers. Several directions were investigated to ultimately add a functional coating providing an antimicrobial effect to textiles. Our strategy relies on the immobilization of silver nanoparticles (AgNPs) and Bi2MoO6 (BMO) – a robust inorganic photocatalyst that can be activated by visible light – microflowers, at the surface of cotton fabric fibers. Notably, an in situ complexation-assisted precipitation route (ISCAP – an original method derived from CPD) was successfully employed to generate a very uniform coating of silver nanoparticles at the surface of organic substrates. As we demonstrate in this study, the surface functionalization with BMO and silver provides a significant protection against bacteria in dark conditions, through a bacteriostatic effect of nano silver, and under low-intensity artificial visible light (thanks to the photocatalytic effect of BMO/Ag), hence suitable for an indoor environment such as hospitals. Our composite nanomaterial, cotton/BMO/AgNPs, was assessed through antibacterial testing with Escherichia coli (E. coli) and Staphylococcus aureus (S. Aureus), showing a pronounced antimicrobial effect with both strains. This study opens prospects for the functionalization of natural or artificial fiber materials with possible applications in the field of biomedical protective equipment such as bandages, masks or technical cloths; or even photocatalysis.

Oxygen Vacancy-Mediated Growth of Amorphous Discharge Products toward an Ultrawide Band Light-Assisted Li-O2 Batteries.

Photoassisted electrochemical reaction is regarded as an effective approach to reduce the overpotential of lithium-oxygen (Li-O2 ) batteries. However, the achievement of both broadband absorption and long term battery cycling stability are still a formidable challenge. Herein, an oxygen vacancy-mediated fast kinetics for a photoassisted Li-O2 system is developed with a silver/bismuth molybdate (Ag/Bi2 MoO6 ) hybrid cathode. The cathode can offer both double advantages for light absorption covering UV to visible region and excellent electrochemical activity for O2 . Upon discharging, the photoexcited electrons from Ag nanoplate based on the localized surface plasmon resonance (LSPR) are injected into the oxygen vacancy in Bi2 MoO6 . The fast oxygen reaction kinetics generate the amorphous Li2 O2 , and the discharge plateau is improved to 3.05V. Upon charging, the photoexcited holes are capable to decompose amorphous Li2 O2 promptly, yielding a very low charge plateau of 3.25V. A first cycle round-trip efficiency is 93.8% and retention of 70% over 500 h, which is the longest cycle life ever reported in photoassisted Li-O2 batteries. This work offers a general and reliable strategy for boosting the electrochemical kinetics by tailoring the crystalline of Li2 O2 with wide-band light.

Ferroelectrics in Photocatalysis.

The rapid development of industrialization and population has brought water, air-pollution and energy crises. Solar-driven catalysis is expected to relieve these issues. However, limited by poor light harvesting, serious charge recombination of semiconductors, and high surface reaction barriers, the low efficiency of solar conversion is far from satisfactory for industrial needs. Ferroelectrics are considered to be promising photocatalysts to overcome these shortcomings. Herein, perovskite ferroelectrics such as BaTiO3 , PbTiO3 , BiFeO3 and LiNbO3 , layered bismuth-based ferroelectrics like Bi2 WO6 and Bi2 MoO6 , and other ferroelectrics are introduced, and their crystal structure, polarity source and synthetic method are highlighted. Subsequently, research progress in ferroelectrics for photocatalysis is summarized, including pollution degradation, water splitting and CO2 reduction. Finally, the current challenges and future prospects of ferroelectric photocatalysts are provided. The purpose of this review is not only to provide a timely summary for the application of ferroelectrics in photocatalysis, but also to present deep insight and a guideline for future research work into ferroelectrics.

Selective Production of Secondary Amine by the Photocatalytic Cascade Reaction Between Nitrobenzene and Benzyl Alcohol over Nanostructured Bi2 MoO6 and Pd Nanoparticles Decorated with Bi2 MoO6.

The synthesis of secondary amine by the photoalkylation of nitrobenzene with benzyl alcohol using a simple light source and sunlight is a challenging task. Herein, a one-pot cascade protocol is employed to synthesize secondary amine by the reaction between nitrobenzene and benzyl alcohol. The one-pot cascade protocol involves four reactions: (a) photocatalytic reduction of nitrobenzene to aniline, (b) photocatalytic oxidation of benzyl alcohol to benzaldehyde, (c) reaction between aniline and benzaldehyde to form imine, and (d) photocatalytic reduction of imine to a secondary amine. The cascade protocol to synthesize secondary amine is accomplished using Bi2 MoO6 and Pd nanoparticles decorated Bi2 MoO6 catalysts. The surface characteristics, oxidation states, and elemental compositions of the materials are characterized by several physicochemical characterization techniques. Optoelectronic and photoelectrochemical measurements are carried out to determine the bandgap, band edge potentials, photocurrents, charge carrier's separation, etc. An excellent yield of secondary amine is achieved with simple household white LED bulbs. The catalyst also exhibits similar or even better activity in sunlight. The structure-activity relationship is established using catalytic activity data, control reactions, physicochemical, optoelectronic characteristics, and scavenging studies. Bi2 MoO6 and Pd nanoparticles decorated Bi2 MoO6 exhibit excellent photostability and recyclability. The simple catalyst design with a sustainable and economical light source for the synthesis of useful secondary amine from the nitrobenzene and benzyl alcohol would attract the researchers to develop similar catalytic protocols for other industrially important chemicals.