Solar Light Illumination Research Articles

Photoelectrochemical Degradation of Organic Pollutants Coupled with Molecular Hydrogen Generation Using Bi2O3/TiO2 Nanoparticle Arrays

The growing world population is closely associated with the increased demand of safe drinking water and sustainable energy production. This drives the focus of the scientific community to work toward water remediation and clean energy generation. The combination of photoelectrooxidation of pollutants at the anode with simultaneous hydrogen gas production at the cathode is a smart strategy to address these problems. Herein, we have designed a bifunctional photoelectrocatalytic system consisting of a self-standing photoanode to degrade the water pollutant molecules with simultaneous production of molecular hydrogen at the cathode. The photoanode was prepared by coating Bi2O3 over the surface of self-standing TiO2 nanorods. Thus, prepared photoelectrodes show high degradation efficiency for rhodamine molecules, where direct oxidation of rhodamine by the holes generated under solar light illumination was detrimental for its activity. During simultaneous pollutant removal and energy production experiments, the anode shows 100% degradation of pollutant molecules while the cathode shows high hydrogen gas production (128 mM cm–2 h–1). The prepared composite showed higher efficiency of visible-light absorbance, high charge generation capability, and low charge transfer resistance at the interface as determined via several characterizations, compared to the bare titania. The catalyst is easy to prepare and robust in activity for several kinds of pollutant molecules tested. Its robust activity, high stability, and durability open up an avenue for the wastewater treatment with simultaneous renewable energy production technologies.

New light on the photocatalytic performance of NH4V4O10 and its composite with rGO

Solar-driven photocatalysis has shown great potential as a sustainable wastewater treatment technology that utilizes clean solar energy for pollutant degradation. Consequently, much attention is being paid to the development of new, efficient and low-cost photocatalyst materials. In this study, we report the photocatalytic activity of NH4V4O10 (NVO) and its composite with rGO (NVO/rGO). Samples were synthesized via a facile one-pot hydrothermal method and successfully characterized using XRD, FTIR, Raman, XPS, XAS, TG-MS, SEM, TEM, N2 adsorption, PL and UV‒vis DRS. The results indicate that the obtained NVO and NVO/rGO photocatalysts exhibited efficient absorption in the visible wavelength region, a high content of V4+ surface species and a well-developed surface area. Such features resulted in excellent performance in methylene blue photodegradation under simulated solar light illumination. In addition, the composite of NH4V4O10 with rGO accelerates the photooxidation of the dye and is beneficial for photocatalyst reusability. Moreover, it was shown that the NVO/rGO composite can be successfully used not only for the photooxidation of organic pollution but also for the photoreduction of inorganic pollutants such as Cr(VI). Finally, an active species trapping experiment was conducted, and the photodegradation mechanism was discussed.

Construction of novel 0D/2D AgI/CAU-17 heterojunction with excellent photocatalytic performance by in situ deposition-precipitation

Dye effluent is a serious threat to water ecosystem and human health, so it is urgent to develop high-efficient and stable semiconductor photocatalysts to solve the water pollution problem. A novel AgI/CAU-17 composite with 0D/2D hierarchical heterostructure was first constructed by growing AgI particles on CAU-17 nanorods via a mild deposition-precipitation procedure. The optimal 50% AgI/CAU-17 composite displayed the greatest photodegradation rate of 96.7% for RhB, 81.3% for TC and 50.3% for MO, under the simulated solar-light illumination for 70 min. The corresponding apparent rate constants were 0.04401, 0.02227 and 0.01104 min−1, which were 23.79, 15.25 and 19.73-times higher than those of CAU-17, and 4.94, 1.79 and 6.29-times higher than those of AgI. The improved photodegradation performance could be owing to the following causes: 1) The 0D/2D hierarchical heterostructure endowed AgI/CAU-17 composite with tight interfacial contact, which could supply sufficient channels for the migration of photoinduced carriers; 2) The type II charge migrate pathway facilitated the segregation and migration of photoexcited carriers; 3) The AgI/CAU-17 heterostructures reinforced the light absorption capacity and augmented the specific surface area. In addition, various photocatalytic conditions were researched to imitate the degradation process of RhB in the real aqueous system. The radical capture experiments and EPR test attested that h+ and •O2- played an important part in the photodegradation of RhB. This study illustrated the tremendous application potential of AgI/CAU-17 heterojunctions in water purification and provided a simple and reliable idea for the preparation of Bi-MOFs composite photocatalysts.

N-doped and sulfur vacancy-rich TiO2@SnS2 nanoporous arrays for the plasmonic photocatalytic H2 evolution

An elegant templating method has been developed for the rational design and synthesis of hierarchical SnS2 nanoclusters composed of ultrathin nanosheets and embedded inside TiO2 nanoporous arrays. Herein, benefiting from their unique structural merits and metal-like plasmonic activity, the TiO2@SnS2 heterostructures exhibit enhanced photocatalytic H2 evolution properties in terms of good cycling performance. S vacancies and N-doping are proved to be vitally important to the electronic structures and bandgap of SnS2, thus influence the plasmonic property and separation of photo-carriers. The optimized TiO2@6nmSnS2/N nanoporous arrays give an ultra-high H2 yield rate of 285 μmol h−1cm−2 under a low catalyst loading mass, that comparable to most noble metal catalysts. Remarkable cycling performance with a capability retention of 90% is achieved after 30 h under solar light illumination. As an innovative exploration, this study demonstrates that the photocatalytic activities of nonmetal, earth-abundant SnS2 can be enhanced with plasmonic effect, which may serve as an excellent catalytic agent for solar energy conversion to chemical fuel.

Investigate the suitability of g-C3N4 nanosheets ornamented with BiOI nanoflowers for photocatalytic dye degradation and PEC water splitting

The two-step thermal polymerization and solvothermal approach is used to construct nano heterostructures of FCN and BiOI (bismuth oxeye iodide), both of which are Nobel metal-free materials. This work reports the effect nano-heterostructure on the micro-structural, light absorption capability, PEC properties and pollutant degradation efficiency of the synthesised heterostructures. The addition to that formation of FCN/BiOI nano-heterostructure enhances the solar light absorption. The FCN/BiOI nano heterostructure shows 10 times higher photocurrent density than the BCN nanostructure and 3.8 time higher that FCN. The FCN/BiOI has a high induced photo-current density (20.17 mA/cm2) and H2 evolution rate (3762 μmol h−1 cm−2) under solar light illumination (λ ≥ 420 nm) in comparison with the other. Furthermore, the photocatalytic performance of this material for the breakdown of methyl red dyes was much greater. Under solar light irradiation, the azo dyes were degraded in 90 min. The FCN/BiOI nano-heterostructure has a higher dye degradation efficiency of 97.91%. The rapid transport of photo-induced electrons in the FCN/BiOI nanocomposite is responsible for the improvement in PEC and PC performances. These impressive findings suggest that this nanocomposite might be used to facilitate the PEC water splitting and the PC degradation of MR in the presence of light. The current research provides insight on how to best tailor composition and structure for efficient FCN photo-electrocatalysis water splitting and Methyl red dye degradation.

Enhanced Photocatalytic Properties of g-C3N4/ZnO/Attapulgite (CNZATP) Composite Nano-Mineral Materials on Methylene Blue Dye Degradation

A nano-ZnO semiconductor material loaded with mineral attapulgite (ATP) photocatalyst has been investigated. Using ATP as a carrier, a variety of various mixtures of ZnO/ATP composites was synthesized. A scanning electron microscope (SEM), X-ray diffractometry (XRD), and UV-Vis spectrophotometer (UV-Vis) were used to examine the morphology, synergistic effects, and photocatalytic properties of ZnO/ATP nanocomposites. The target pollutant for photocatalytic degradation is methylene blue solution. When ATP is mixed with pure ZnO, the degrading performance of composite nanomaterials in methylene blue solution is considerably enhanced. The degree of methylene blue degradation increases as the amount of ATP in the composite grows, and the degradation rate of ZnO/40% ATP can reach 96% in 45 min under solar light illumination. The amount of ATP in the system is excessive, and the adsorption effect is visible. The optimal composite ratio was determined to be ZnO/30% ATP. After discovering the ideal composite ratio and synergy of ZnO/ATP, g-C3N4 was compounded in the aforesaid system, dramatically increasing the composite’s photocatalytic activity. At 45 min, the degradation rate of methylene blue reaches 97%. The absorption range and intensity of ternary composites increased, and the photogenerated electron-hole recombination rate decreases significantly. The reaction rate constant increases from 0.033 to 0.069 min−1. SEM revealed rod-like attapulgite particles packed with tiny zinc oxide particles and a moderate layered structure of C3N4. The XRD pattern indicated that C3N4’s crystallinity is poor and ZnO’s peak intensity is excessively high, masking the composite material’s distinctive peaks. The degradation rate of g-C3N4/ZnO/30% ATP to methylene blue was found to be 91.5% after 5 cycles.

Highly active and stable CuAlOx/WO3 photoanode for simultaneous pollutant degradation, hydrogen and electricity generation

An unassisted solar water-energy nexus system (SWENS) based on an ultra-thin CuAlOx overlayer coated WO3 nanoplate array (CuAlOx/WO3) photoanode, a rear silicon solar cell and a Pt-black/Pt cathode was proposed to efficiently degrade refractory organic pollutants and simultaneously produce hydrogen and electricity. The formed p-n junction between p-type CuAlOx and n-type WO3 effectively facilitated the charge separation in the CuAlOx/WO3 photoanode. Moreover, the CuAlOx overlayer enhanced the capture of photogenerated holes and isolated WO3 from the solution, thereby improving the charge transfer and inhibiting the photocorrosion of WO3. Therefore, the optimized CuAlOx/WO3 photoanode showed a significantly enhanced and stable photocurrent density of ∼2.82 mA cm−2 at 1.0 V vs. Ag/AgCl, which was ∼4 times higher than that of the pristine WO3. Based on this outstanding photoelectrocatalytic performance, the assembled SWENS showed a degradation efficiency of nearly 100% for tetracycline, a hydrogen generation rate of ∼26.8 μmol·h−1·cm−2 and a power density of ∼593 μW cm−2 under simulated solar light illumination. Our SWENS also exhibited outstanding universality in degrading various refractory organic pollutants for green energy production.

Ba4X][In19S32] (X = Cl, Br): two quaternary metal chalcohalides exhibiting remarkable photocurrent responses.

Inorganic metal chalcohalides, as significant semiconductor materials, have emerged as promising candidates for photoelectric applications. Herein, a new type of quaternary chalcohalide, [Ba4X][In19S32] (X = Cl, Br), has been discovered using the high-temperature halide salt flux method. Single-crystal X-ray diffraction analysis reveals that they are isostructural and crystallize in the tetragonal space group I41/amd (no. 141) featuring the octahedral hole formed by six [InS4]5- tetrahedra filled with a [ClBa4]7+ polycation, surrounded by a three-dimensional covalent framework formed by interconnecting [InS6]9- octahedra through corner-sharing and edge-sharing. Moreover, [Ba4Cl][In19S32] and [Ba4Br][In19S32] exhibit wide optical bandgaps of 2.70 eV and 2.46 eV, respectively, and moderate birefringences (0.044 @ 2100 nm and 0.042 @ 2100 nm, respectively). Specifically, [Ba4X][In19S32] (X = Cl, Br) display remarkable photocurrent responses under simulated solar-light illumination, implying their potential for photocatalytic applications. Theoretical calculations were employed to understand the interrelationship between the optical properties and electronic structure. The study on the synthesis and structure-property relationship analysis of inorganic metal chalcohalides provides new insight into the exploration of promising photoelectric materials.

Elemental sulfur supported on ultrathin titanic acid nanosheets for photocatalytic reduction of CO2 to CH4

The photocatalytic reduction of CO2 into energy-intensive hydrocarbon fuels is promising to solve environment and energy issues. Here, elemental sulfur supported on ultrathin titanic acid nanosheets (S/HTO) heterostructure is designed and synthesized by loading different weight contents of elemental S on HTO nanosheets via a simple in-situ disproportionation-assembly process. The as-designed S/HTO heterostructure not only enhances light absorption and facilitates CO2 adsorption, but also significantly promotes the interfacial charge transport, and suppresses the recombination of photogenerated charge carriers. As a consequence, the as-prepared S/HTO heterostructure exhibits enhanced performance in photocatalytic CO2 reduction under simulated solar light illumination. A CH4 yield rate of 1.92 μmol h−1 g−1 is obtained over the optimal 15S/HTO composite without the using of cocatalyst and sacrificial agent. The photoactivity is 5.4-fold and 23-fold larger than that of HTO nanosheets and blank S, respectively. In addition, the S/HTO hybrid composite also presents high stability for the production of CH4.

Synthesis of highly efficient selenium oxide hybridized g-C3N4 photocatalyst for NADH/NADPH regeneration to facilitate solar-to-chemical reaction

An inexpensive graphitic carbon nitrite (g-C3N4) photocatalyst was hybridized with selenium oxide (SeO2) photocatalyst by a monolayer-dispersed technique. After hybridization of g-C3N4 with SeO2, the NADH/NADPH regeneration efficiency of SeO2 photocatalyst was enhanced under solar light illumination. The photocatalytic activity of SeO2/g-C3N4 photocatalyst under solar light illumination was enhanced by 3-fold higher than g-C3N4 photocatalyst, the solar light photocatalytic activity was produced and the photo-decomposition of SeO2 photocatalyst was completely stifled after hybridized SeO2 photocatalyst by g-C3N4 photocatalyst. The improvement in performance and photo-decomposition inhibition under solar light illumination was persuaded by efficiency separation of photo-persuaded holes from SeO2 to the valence bond (V.B.)/highest occupied molecular orbital (HOMO) of g-C3N4 under solar light illumination, the electron jumped from the V.B. to the conduction band (C.B.)/lowest unoccupied molecular orbital (LUMO) of g-C3N4 could directly insert into the C.B. of SeO2 photocatalyst, synthesized SeO2/g-C3N4 photocatalyst is highly active for NADH/NADPH regeneration under solar light.

In situ synthesis of polypyrrole/Nd-doped ZnO nanocomposite with enhanced visible light photocatalytic performance for the degradation of organic dyes

In water resources, organic dyes are known as poisonous substances. As a result, photocatalytic treatment of pollutants has been implemented to address water quality challenges. In the present study, nanocomposite of Nd-doped ZnO (ZnO:Nd) and polypyrrole (PPy) was synthesized via in-situ polymerization to enhance the photodegradation of Methyl orange (MO) and Methylene blue (MB). The formation of PPy/ZnO:Nd nanocomposite was confirmed using Fourier-transform infrared spectra (FTIR) and X-ray diffraction (XRD). The activation energy and thermal stability of prepared samples were investigated by Simultaneous Thermal Analysis (STA). X-ray photoelectron spectroscopy (XPS) demonstrated that Nd atoms were successfully doped into the ZnO crystal structure. Microstructure images of powders were captured using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). UV–vis spectroscopy was employed to examine optical properties, revealing that the band gap energies of pure ZnO decreased from 3.29 eV to 1.8 eV upon doping with Nd atoms and coupling with PPy as a conductive polymer. PPy/20%ZnO:Nd nanocomposite has the highest MO and MB degradation efficiency of all synthesized powders. Using the Langmuir-Hinshelwood model, the reaction rate constant (k) of PPy/ZnO:Nd was calculated to be approximately 8 times faster than ZnO nanoparticles. After 5 cycles, the stability of the fabricated nanocomposite under visible radiation showed a slight decrease in catalyst efficiency. Therefore, this novel PPy/ZnO:Nd nanocomposite is an eco-friendly candidate for wastewater remediation due to its effective photocatalytic performance under solar light illumination.

Process Accumulated 8% Efficient Cu2ZnSnS4‐BiVO4 Tandem Cell for Solar Hydrogen Evolution with the Dynamic Balance of Solar Energy Storage and Conversion

A process accumulated record solar to hydrogen (STH) conversion efficiency of 8% is achieved on the Cu2 ZnSnS4 -BiVO4 tandem cell by the synergistic coupling effect of solar thermal and photoelectrochemical (PEC) water splitting with the dynamic balance of solar energy storage and conversion of the greenhouse system. This is the first report of a Cu2 ZnSnS4 -BiVO4 tandem cell with a high unbiased STH efficiency of over 8% for solar water splitting due to the greenhouse device system. The greenhouse acts as a solar thermal energy storage cell, which absorbs infrared solar light and storage as thermal energy with the solar light illumination time, while thermoelectric device (TD) converts thermal energy into electric power, electric power is also recycled and added onto Cu2 ZnSnS4 -BiVO4 tandem cell for enhanced overall water splitting. Finally, the solar water splitting properties of the TD-Cu2 ZnSnS4 -BiVO4 integrated tandem cell in pure natural seawater are demonstrated, and a champion STH efficiency of 2.46% is presented, while a large area (25cm2 ) TD-Cu2 ZnSnS4 -BiVO4 integrated tandem device with superior long-term stability is investigated for 1 week, which provides new insight into photoelectrochemical solar water splitting devices.

1T-phase MoS2/holey ultrathin g-C3N4 nanosheets based 2D/2D heterostructure for enhanced photocatalytic hydrogen production

Although graphitic carbon nitride (g-C3N4) is widely used for photocatalytic hydrogen production, its practical application is restricted by the high recombination rate of photoinduced electron-hole pairs and limited active sites. In this work, holey ultrathin g-C3N4 nanosheets (HCN NSs) with rich active sites are prepared, followed by the growth of 1T-MoS2 NSs on their surfaces to construct 2D/2D 1T-MoS2/HCN heterostructure. Due to the high surface area and abundant hydrogen active sites of the hybrid, large and intimate 2D nanointerface between MoS2 and HCN, hydrogen ion adsorption and charge separation/transport ability are greatly enhanced. As a result, 1T-MoS2/HCN-4 with the optimal 1T-MoS2 content of 8 wt% displays the highest H2 production rate of 2724.2 μmol−1 h−1 g−1 under simulated solar light illumination with apparent quantum efficiency of 8.1% (λ = 370 nm). Moreover, the 1T-MoS2/HCN-4 hybrid manifests improved stability after a long-time test. This study opens the door to design highly-efficient g-C3N4 based 2D/2D heterostructures for photocatalytic H2 production.

Sunlight-active hierarchical Ag@insulator@ZnO core-shell array based on natural diatoms for environmental remediation

A nature inspired plasmonic core-shell architecture was proposed by incorporating a natural siliceous insulator shell (Navicula salinicola frustules) in Ag/diatomite/ZnO hierarchical nanostructures to overcome the recombination of energetic charge carriers (e−/h+), corrosion of bare metal, and to facilitate the composite separation after reaction. The photocatalytic performance of the as-prepared composites, monitored by decomposition of methylene blue (MB), was investigated under both UV and simulated sunlight irradiation. Ag/diatomite/ZnO exhibited efficient photocatalytic performance (near 100% degradation and 95% mineralization) under simulated sunlight irradiation with apparent rate constant of 0.0246 min−1, which was found to follow pseudo-first order kinetics. The enhanced photocatalysis action of metal/insulator/semiconductor as compared to metal/semiconductor and the semiconductor alone could be ascribed to the synergistic effects of the photonic structure of regular frustules, improved sunlight harvesting efficiency, suppressed back electron transfer, and prohibited oxidization of Ag. While the as-synthesized composite was easy to separate from the reaction, however, it was in the throes of losing the photocatalytic activity after three rounds of reuse. A possible mechanism of photocatalytic degradation of MB induced by Ag/diatomite/ZnO under sunlight irradiation was proposed based on dye degradation measurements and reactive species trapping experiments. While the reusability of as-prepared composite will doubtless be much scrutinized, our study may provide a new insight into the design and fabrication of plasmonic-based nanomaterials for use in industry applications under solar light illumination.

Hydrothermal Synthesis of Cadmium Sulfide Photocatalyst for Detoxification of Azo Dyes and Ofloxacin Antibiotic in Wastewater.

The complete detoxification of harmful dyes and antibiotics from aqueous solution is essential for environmental remediation. The present work focuses on a facile hydrothermal synthesis of a cadmium sulfide (CdS) photocatalyst using thioacetamide as a sulfur source. The synthesized CdS showed a hexagonal phase with an energy gap of 2.27 eV, suggesting the promising visible-light-responsive semiconducting photocatalyst. The photoactivity of the prepared CdS was investigated by evaluating the degradation of the Reactive red 141 (RR141) dye, Congo red (CR) dye, and ofloxacin (OFL) antibiotic. After only 180 min of solar light illumination, a high performance of 98%, 97%, and 87% toward degradation of RR141, CR, and OFL was obtained. The photodegradation of the pollutants agrees well with the first-order kinetic model. The rate constant of 0.055 min-1, 0.040 min-1, and 0.026 min-1, respectively, was reported toward degradation of RR141, CR, and OFL. Photogenerated holes and hydroxyl radicals play a vital role in removing toxic organic contaminants. The chemical stability of the prepared CdS was also confirmed. The synthesized CdS photocatalyst still maintains high photocatalytic performance even after five consecutive cycles of use, indicating its excellent cycling ability. The present research shows a facile route to fabricate a CdS photocatalyst to completely detoxify harmful organic pollutants, including dyes and antibiotics, in the environment.

Boosting Photoelectrochemical Ethanol Evolution on Reduced Graphene Oxide Functionalized Photocathode

AbstractHerein, a reduced graphene oxide (rGO) functionalized photocathode is studied for selective production of solar liquid fuels depending on dark and solar light illumination condition. rGO functionalized photocathode with p–n junction at the core–shell interface of ZnO@ZnTe is prepared with a three‐step synthetic process. Preparation of ZnO nanorod, formation of ZnTe on ZnO nanorod by anion‐exchange and then, finally, rGO layers are functionalized on the surface of ZnO@ZnTe photocathode. The photoelectrochemical (PEC) system of BiVO4∥KHCO3∥ZnO@ZnTe@rGO combination is introduced for selective solar liquid fuel production by CO2 reduction reaction (CO2RR). Functionalization of rGO layers on photocathode enables the multi‐electron shuttling function for the enhanced charge transfer efficiency due to its large charge capacitance, which results in producing liquid fuels such as HCHO and EtOH selectively as solar liquid fuels. These results in this work clearly demonstrate a possibility of solar liquid fuel product selectivity by PEC CO2RR.

Spontaneous polarization of ferroelectric heterostructured nanorod arrays for high-performance photoelectrochemical cathodic protection

Corrosion is a critical global problem for the steel industry and a grand challenge toward Net-Zero clean growth. TiO2 nanorods (TNRs) have been developed for photoelectrochemical cathodic protection (PCP) of coupled metal. However, the performance was hindered by their wide bandgap, weak visible-light response, and low separation efficiency of photocarriers. In this work, a unique multilayered coaxial nanorod array (TNRs/BTO/Ag NPs) structure has been proposed to enhance ‘hot’ electrons injection via inserting a ferroelectric semiconductor BaTiO3 (BTO) nanolayer between TNRs and Ag nanoparticles (Ag NPs). The spontaneous ferroelectric BTO nanolayer built a polar charge-induced electric field (PEF), resulting in a strong spontaneous polarization. Furthermore, the as-proposed structure can negatively shift the surface potential of the coupling 304 stainless steel by 0.80 V relative to its corrosion potential under simulated solar light illumination which is the record PCP potential among reported works. Based on comprehensive electrochemical and theoretical studies, the origin of the enhanced photo-generated carriers’ separation and depletion to the coupled metals is attributed to a synergic effect between PEF (the spontaneous polarization of BTO) and internal electric field (IEF) resulting from the cascade energy band alignment. Various promising applications can be envisioned from as-proposed multilayered coaxial nanorod array photoelectrodes.

Effect of Ag-Decorated BiVO4 on Photoelectrochemical Water Splitting: An X-ray Absorption Spectroscopic Investigation.

Bismuth vanadate (BiVO4) has attracted substantial attention on account of its usefulness in producing hydrogen by photoelectrochemical (PEC) water splitting. The exploitation of BiVO4 for this purpose is yet limited by severe charge recombination in the bulk of BiVO4, which is caused by the short diffusion length of the photoexcited charge carriers and inefficient charge separation. Enormous effort has been made to improve the photocurrent density and solar-to-hydrogen conversion efficiency of BiVO4. This study demonstrates that modulating the composition of the electrode and the electronic configuration of BiVO4 by decoration with silver nanoparticles (Ag NPs) is effective in not only enhancing the charge carrier concentration but also suppressing charge recombination in the solar water splitting process. Decoration with a small number of Ag NPs significantly enhances the photocurrent density of BiVO4 to an extent that increases with the concentration of the Ag NPs. At 0.5% Ag NPs, the photocurrent density approaches 4.1 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (RHE) under solar simulated light illumination; this value is much higher than the 2.3 mA cm−2 of pure BiVO4 under the same conditions. X-ray absorption spectroscopy (XAS) is utilized to investigate the electronic structure of pure BiVO4 and its modification by decoration with Ag NPs. Analytical results indicate that increased distortion of the VO4 tetrahedra alters the V 3d–O 2p hybridized states. Additionally, as the Ag concentration increases, the oxygen vacancy defects that act as recombination centers in BiVO4 are reduced. In situ XAS, which is conducted under dark and solar illumination conditions, reveals that the significantly enhanced PEC performance is attributable to the synergy of modulated atomic/electronic structures and the localized surface plasmon resonance effect of the Ag nanoparticles.

Investigations into the Antifungal, Photocatalytic, and Physicochemical Properties of Sol-Gel-Produced Tin Dioxide Nanoparticles.

Transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and Fourier transform infrared (FTIR) spectroscopy were applied to evaluate the tin dioxide nanoparticles (SnO2 NPs) amalgamated by the sol-gel process. XRD was used to examine the tetragonal-shaped crystallite with an average size of 26.95 (±1) nm, whereas the average particle size estimated from the TEM micrograph is 20.59 (±2) nm. A dose-dependent antifun3al activity was performed against two fungal species, and the activity was observed to be increased with an increase in the concentration of SnO2 NPs. The photocatalytic activity of SnO2 NPs in aqueous media was tested using Rhodamine 6G (Rh-6G) under solar light illumination. The Rh-6G was degraded at a rate of 0.96 × 10−2 min for a total of 94.18 percent in 350 min.

Hydrogen-substituted graphdiyne encapsulated cuprous oxide photocathode for efficient and stable photoelectrochemical water reduction

Photoelectrochemical (PEC) water splitting is an appealing approach for “green” hydrogen generation. The natural p-type semiconductor of Cu2O is one of the most promising photocathode candidates for direct hydrogen generation. However, the Cu2O-based photocathodes still suffer severe self-photo-corrosion and fast surface electron-hole recombination issues. Herein, we propose a facile in-situ encapsulation strategy to protect Cu2O with hydrogen-substituted graphdiyne (HsGDY) and promote water reduction performance. The HsGDY encapsulated Cu2O nanowires (HsGDY@Cu2O NWs) photocathode demonstrates a high photocurrent density of −12.88 mA cm−2 at 0 V versus the reversible hydrogen electrode under 1 sun illumination, approaching to the theoretical value of Cu2O. The HsGDY@Cu2O NWs photocathode as well as presents excellent stability and contributes an impressive hydrogen generation rate of 218.2 ± 11.3 μmol h−1cm−2, which value has been further magnified to 861.1 ± 24.8 μmol h−1cm−2 under illumination of concentrated solar light. The in-situ encapsulation strategy opens an avenue for rational design photocathodes for efficient and stable PEC water reduction.