Hydrothermal Synthesis Research Articles

Microporosity and Catalytic Activity for Hydrodesulfurization of Pharmacosiderite Mo4P3O16 Synthesized at a Moderate Temperature.

Pharmacosiderite Mo4P3O16 (Pharma-MoPO) consists of [Mo4O4] cubane unit and [PO4] tetrahedral to form an open framework with a microporous structure similar to that of LTA-type zeolite. Although attractive applications are expected due to its microporous structure and redox-active components, its physicochemical properties have been poorly investigated due to the specificity of its synthesis, which requires a high hydrothermal synthesis temperature of 360 °C. In this study, we succeeded in synthesizing Pharma-MoPO by hydrothermal synthesis at 230 °C, which can be applied using a commercially available autoclave by changing the metal source. Through the study of the solids and liquids obtained after hydrothermal syntheses, the formation process of Pharma-MoPO under our studied synthesis conditions was proposed. Advanced characterizations provided detailed structural information on Pharma-MoPO, including the location site of a countercation NH4+. Pharma-MoPO could adsorb CO2 with the amount close to the number of cages without removing NH4+. Pharma-MoPO exhibited stable catalytic activity for the hydrodesulfurization of thiophene while maintaining its crystal structure, except for the introduction of sulfide by replacing lattice oxygens. Pharmacosiderite Mo4P3O16 was successfully obtained by hydrothermal synthesis at a moderate temperature, and its microporosity for CO2 adsorption and catalytic properties for hydrodesulfurization were discovered.

Kinetic study and advanced decomposition models of superthermite-based nitrocellulose nanocomposite

ABSTRACT Superthermites are well-known for their exceptional combustion characteristics. α ferric oxide nanoparticles (NPs) were synthesized using hydrothermal synthesis. Co-precipitation technique was employed to integrated superhermite (Al/Fe2O3) colloidal particles into nitrocellulose (NC) energetic matrix. Morphology NC nanocomposite was investigated using scanning electron microscope. The integration of superthermite particles into NC matrix experienced enhanced decomposition enthalpy by 40% using Differential Scanning Calorimetry (DSC) as the decomposition enthalpy has incresed to reach above 1640J/kg. In the mean time, superthermite particles offered decrease in NC activation energy by 17.3% and 16.0% using Kissinger-Akahira-Sunose (KAS) approach and Kissinger models, respectively. The hydrous surface of ferric NPs could secure novel catalytic action. At low temperatures, the reactive hydroxyl groups could be released; active ȮH radicals would attack the NC heterocyclic ring and abstract hydrogen atom. Addition of NPs enhanced the rapid release of different decomposition products of NC such as NO2 ,CO, NO, HCHO, and HCOOH at low temperature. Kinetic models indicated that the heterogeneous solid-state reaction and A2 nucleation model were confirmed via KAS and Kissinger models.

Gap type effect on photocatalytic degradation using newly hydrotalcite nanoposite precursor synthesized by hydrothermal method

<p>A novel technique involving hydrothermal synthesis was employed to prepare nanocomposite precursors of lamellar double hydroxide based basic mixed oxides. This method extended ongoing research on iron-impregnated hydrotalcite-supported nanomaterials. The iron-based Fe/MgAl-h nanocomposite was prepared via dry impregnation, introducing a known % by weight of Fe (NO3)3.9H2O metal salt into the hydrothermally synthesized MgAl-h structure. For comparative analysis, the photocatalytic performance of Fe/MgAl-h was compared with the coprecipitation-synthesized Fe/MgAl-c after calcination at 400°C, using various characterization techniques. Structural examination revealed a double-layered hydroxyl structure and the presence of iron oxide phase Fe2O3 in Fe/MgAl-h400. Optical assessments indicated an indirect band gap energy of 1.89 eV for solid Fe/MgAl-h400, which is suitable for visible light absorption. Photocatalytic experiments for methylene blue (MB) dye degradation in aqueous solution were performed under artificial irradiation with a tungsten lamp as the visible light source, mirroring the conditions of Fe/MgAl-c400. Using 50 mg/L MB concentration and 0.5 g/L catalyst quantity, increased MB removal efficiency with time was observed. A comparative study of hydrothermal and coprecipitation synthesis methods showed decreased photodegradation for the hydrothermally prepared solid. Fe/MgAl-h400 and Fe/MgAl-c400 exhibited reaction efficiencies of approximately 46% and 67%, respectively, possibly attributed to their distinct indirect and direct band gap characteristics. Moreover, a wider band gap in a semiconductor material offers several advantages for the degradation of dyes.</p>

Microwave-Assisted Hydrothermal Synthesis of Na3V2(PO4)2F3 Nanocuboid@Reduced Graphene Oxide as an Ultrahigh-Rate and Superlong-Lifespan Cathode for Fast-Charging Sodium-Ion Batteries.

Na3V2(PO4)2F3 (NVPF) has been regarded as a favorable cathode for sodium-ion batteries (SIBs) due to its high voltage and stable structure. However, the limited electronic conductivity restricts its rate performance. NVPF@reduced graphene oxide (rGO) was synthesized by a facile microwave-assisted hydrothermal approach with subsequent calcination to shorten the hydrothermal time. NVPF nanocuboids with sizes of 50-150 nm distributed on rGO can be obtained, delivering excellent electrochemical performance such as a longevity life (a high capacity retention of 85.6% after 7000 cycles at 10 C) and distinguished rate capability (116 mAh g-1 at 50 C with a short discharging/charging time of 1.2 min). The full battery with a Cu2Se anode represents a capacity of 116 mAh g-1 at 0.2 A g-1. The introduction of rGO can augment the electronic conductivity and advance the Na+ diffusion speed, boosting the cycling and rate capability. Besides, the small lattice change (3.3%) and high structural reversibility during the phase transition process between Na3V2(PO4)2F3 and NaV2(PO4)2F3 testified by in situ X-ray diffraction are also advantageous for Na storage behavior. This work furnishes a simple method to synthesize polyanionic cathodes with ultrahigh rate and ultralong lifespan for fast-charging SIBs.

Electrochemical Deposition and Properties of Ni Coatings with Nitrogen-Modified Graphene Oxide

In this study, a method for producing nitrogen-modified graphene oxide (NMGO) using hydrothermal synthesis in the presence of triethanolamine is presented. The composition and structure of NMGO are characterized using X-ray phase analysis (XPA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and Raman spectroscopy. Ni-based metal matrix coatings (MMCs) modified with NMGO were obtained from a sulfate-chloride electrolyte in the galvanostatic mode. The process of electrochemical deposition of these coatings was studied using chronovoltammetry. The microstructure of Ni–NMGO MMCs was studied using the XPA and SEM methods. It has been established that the addition of NMGO particles into the Ni matrix results in an increase in the microhardness of the resulting coatings by an average of 1.30 times. This effect is a consequence of the refinement of crystallites and high mechanical properties of NMGO phase. The corrosion-electrochemical behavior of studied electrochemical deposits in 0.5 M sulfuric acid was analyzed. It has been shown that the corrosion rate of Ni–NMGO MMCs in a 3.5% sodium chloride environment decreases by approximately 1.50–1.70 times as compared to unmodified Ni coatings. This is due to NMGO particles that act as a barrier preventing the propagation of the corrosion and form corrosive galvanic microelements with Ni, promoting anodic polarization.

Chiral Transfer and Evolution in Cysteine Induced Cobalt Superstructures.

Chiral organic additives have unveiled the extraordinary capacity to form chiral inorganic superstructures, however, complex hierarchical structures have hindered the understanding of chiral transfer and growth mechanisms. This study introduces a simple hydrothermal synthesis method for constructing chiral cobalt superstructures with cysteine, demonstrating specific recognition of chiral molecules and outstanding electrocatalytic activity. The mild preparation conditions allow in situ tracking of chirality evolution in the chiral cobalt superstructure, offering unprecedented insights into the chiral transfer and amplification mechanism. The resulting superstructures exhibit a universal formation process applicable to other metal oxides, extending the understanding of chiral superstructure evolution. This work contributes not only to the fundamental understanding of chirality in self-assembled structures but also provides a versatile method for designing chiral inorganic nanomaterials with remarkable molecular recognition and electrocatalytic capabilities.

A study on the optimization and functionalization of zirconia-coated multi-walled carbon nanotubes through hydrothermal process

Abstract Carbon nanotubes (CNTs) have emerged as revolutionary nanomaterials with exceptional properties. This study focuses on optimizing acid treatment conditions for functionalizing multi-walled carbon nanotubes (MWCNTs) and investigates the synthesis of zirconia-coated CNTs. Acid treatment was conducted with HNO3 and H2SO4 their combinations with different molarity concentrations. Acid oxidation, particularly with nitric acid, enhances CNT solubility and reactivity. The research explores the incorporation of acid-treated MWCNTs into ceramic composites, addressing challenges in dispersion and bonding. Additionally, a hydrothermal process is employed to coat MWCNTs with zirconia, contributing to the development of nanocomposites with unique properties. Characterization studies, including SEM, TEM, XRD, and Raman spectroscopy, provide insights into structural and chemical aspects. The findings contribute to advancing the application of CNT-based nanocomposites in various technological fields. The study's methodology, involving acid treatment optimization and hydrothermal synthesis, provides a robust foundation for further advancements in the field of nanomaterials and composites. This novel approach results in ZrO2-coated CNTs, showcasing potential applications in catalysts, oxygen sensors, fuel cells, and electronic devices.

Commercializable Naphthalene Diimide Anolytes for Neutral Aqueous Organic Redox Flow Batteries

Neutral aqueous organic redox flow batteries (AORFBs) hold the potential to facilitate the transition of renewable energy sources from auxiliary to primary energy, the commercial production of anolyte materials still suffers from insufficient performance of high‐concentration and the high cost of the preparation problem. To overcome these challenges, this study provides a hydrothermal synthesis methodology and introduces the charged functional groups into hydrophobic naphthalene diimide cores, and prepares a series of high‐performance naphthalene diimide anolytes. Under the synergistic effect of π‐π stacking and H‐bonding networks, the naphthalene diimide exhibits excellent structural stability and the highest water solubility (1.85 M for dex‐NDI) reported to date. By employing the hydrothermal method, low‐cost naphthalene diimides are successfully synthesized on a hundred‐gram scale of $0.16 g‐1 ($2.43 Ah‐1), which is also the lowest price reported to date. The constructed full battery achieves a high electron concentration of 2.4 M, a high capacity of 54.4 Ah L‐1, and a power density of 318 mW cm‐2 with no significant capacity decay observed during long‐duration cycling. These findings provide crucial support for the commercialization of AORFBs and pave the way for revolutionary developments in neutral AORFBs.

Research progress on ZnO/MoS2/rGO ternary photocatalysts

Energy shortage and environmental pollution have become one of the important global issues, and semiconductor photocatalytic technology is considered as one of the effective means to solve these problems. As a new and efficient green material, ZnO has attracted wide attention. ZnO is widely used in the field of photocatalysis due to its non-toxicity, low cost, environmental friendliness, adjustable band gap, high electron density, and chemical stability. However, the recombination of photogenerated charge carriers in ZnO hinders its practical application and lowers the utilization efficiency of visible light. On the other hand, molybdenum disulfide/reduced graphene oxide (MoS2/rGO), as a binary non-precious metal co-catalyst, has a larger specific surface area, suitable band gap width, and visible light response capability compared to single-phase graphene co-catalyst. Therefore, introducing MoS2/rGO co-catalyst into the ZnO system can provide more active sites, reduce the probability of photogenerated charge carrier recombination, and improve the utilization efficiency of visible light. In this review, we summarize the hydrothermal synthesis methods for preparing this highly demanded nanocomposite material, including one-step and stepwise methods. Subsequently, we elaborate on the mechanism of enhancing light absorption and achieving efficient electron-hole separation behavior in the ternary system heterojunction structure during the photocatalytic process. Due to its significant advantages, this ternary system heterojunction structure has been widely applied in the field of photocatalysis, including applications such as pollutant degradation, sterilization, and water splitting.

Interzeolite Transformation from FAU-to-EDI Type of Zeolite

This study reports for the first time the transformation of the pre-made FAU type of zeolite to the EDI type of zeolite. The concentration of the KOH solution controls this interzeolite transformation, which unusually occurs at both room temperature and under hydrothermal conditions. The transformation involves the amorphization and partial dissolution of the parent FAU phase, followed by the crystallization of EDI zeolite. At room temperature, the transformation (11–35 days) provides access to well-shaped nano-sized crystals and hollow hierarchical particles while the hydrothermal synthesis results in faster crystallization (6–27 h). These findings reveal an example of an interzeolite transformation to a potassium zeolite that lacks common composite building units with the parent zeolite phase. Finally, this work also demonstrates the first room-temperature synthesis of EDI zeolite from a gel precursor.

Commercializable Naphthalene Diimide Anolytes for Neutral Aqueous Organic Redox Flow Batteries.

Neutral aqueous organic redox flow batteries (AORFBs) hold the potential to facilitate the transition of renewable energy sources from auxiliary to primary energy, the commercial production of anolyte materials still suffers from insufficient performance of high-concentration and the high cost of the preparation problem. To overcome these challenges, this study provides a hydrothermal synthesis methodology and introduces the charged functional groups into hydrophobic naphthalene diimide cores, and prepares a series of high-performance naphthalene diimide anolytes. Under the synergistic effect of π-π stacking and H-bonding networks, the naphthalene diimide exhibits excellent structural stability and the highest water solubility (1.85 M for dex-NDI) reported to date. By employing the hydrothermal method, low-cost naphthalene diimides are successfully synthesized on a hundred-gram scaleof $0.16 g-1 ($2.43 Ah-1), which is also the lowest price reported to date. The constructed full battery achieves a high electron concentration of 2.4 M, a high capacity of 54.4 Ah L-1, and a power density of 318 mW cm-2 with no significant capacity decay observed during long-duration cycling. These findings provide crucial support for the commercialization of AORFBs and pave the way for revolutionary developments in neutral AORFBs.

Moisture‐Resistant Orange Emitters with Near‐Unity Quantum Yield from Mn2+ Alloyed Vacancy‐Ordered Quadruple Perovskites

AbstractMn2+‐doped metal halide perovskites present remarkable optical properties in optoelectronic applications, although the realization of high efficiency and stability is still a challenge. In this work, a series of highly efficient and stable orange‐emitting Mn2+ alloyed Cs4Cd1‐xMnxBi2Cl12 single crystals are successfully synthesized via a hydrothermal reaction. Combined with the crystal structure and spectral characterization at 7 K, the site occupation of Mn2+ and defect emission are systematically discussed. Benefiting from the effective [BiCl6]3−→[MnCl6]4− energy transfer and lattice distortion, these single crystals exhibit a maximum internal and external quantum yield of ≈97% and ≈65% at 35% heavy doping level. Interestingly, these Mn2+‐alloyed single crystals exhibit remarkably waterproof stability, no decrease in emission intensity is observed after immersion in deionized water for 4 h. After soaking in deionized water for 100 days, the internal quantum yield can still maintain 44%, implying good chemical stability and moisture resistance due to the formation of protective BiOCl layer. This work provides new insights into the optimization mechanism for Mn2+ luminescence and overcoming the downside of their waterproofing in humid conditions.

Achieving High Isotropic Figure of Merit in Cd and in Codoped Polycrystalline SnSe.

Here, we combined Cd and In codoping with a simple hydrothermal synthesis method to prepare SnSe powders composed of nanorod-like flowers. After spark plasma sintering, its internal grains inherited well the morphological features of the precursor, and the multiscale microstructure included nanorod-shaped grains, high-density dislocations, and stacking faults, as well as abundant nanoprecipitates, resulting in an ultralow thermal conductivity of 0.15 W m-1 K-1 for the synthesized material. At the same time, Cd and In synergistically regulated the electrical conductivity and Seebeck coefficient of SnSe, leading to an enhanced power factor. Among them, Sn0.94Cd0.03In0.03Se achieved a peak ZT of 1.50 parallel to the pressing direction, representing an 87.5% improvement compared with pure SnSe. Notably, the material possesses isotropic ZT values parallel and perpendicular to the pressing direction, overcoming the characteristic anisotropy in thermal performance observed in previous polycrystalline SnSe-based materials. Our results provide a new strategy for optimizing the performance of thermoelectric materials through structural engineering.

Heterointerface engineering in rGO/Ti3C2Tx/TiO2 for broad-band electromagnetic wave absorption

Multi-layer 2D material assemblies introduce numerous interfaces that would improve microwave absorbing. Here, a 3D porous rGO/Ti3C2Tx/TiO2 heterostructure was prepared using a one-step hydrothermal synthesis. Due to the presence of the 2D/2D van der Waals heterojunction in rGO/Ti3C2Tx featuring face-to-face contacts, and the 2D/0D heterojunctions in Ti3C2Tx/TiO2, the interfacial polarization is optimized. The minimum reflection loss (RLmin) achieves −37.31 dB, and the effective absorption bandwidth (EAB) extends to 6.45 GHz (with<−10 dB). These results not only shed light on understanding and enhancement of interfacial effects, but also provides an appealing mode for the implementation of heterogeneous interfacial engineering using tailored 2D hierarchical structures.

Well-Defined Supported ZnOx Species: Synthesis, Structure, and Catalytic Performance in Nonoxidative Dehydrogenation of C3-C4 Alkanes.

ConspectusZinc oxide (ZnO) is a multipurpose material and finds its applications in various fields such as rubber manufacturing, medicine, food additives, electronics, etc. It has also been intensively studied in photocatalysis due to its wide band gap and environmental compatibility. Recently, heterogeneous catalysts with supported ZnOx species have attracted more and more attention for the dehydrogenation of propane (PDH) and isobutane (iBDH) present in shale/natural gas. The olefins formed in these reactions are key building blocks of the chemical industry. These reactions are also of academic importance for understanding the fundamentals of the selective activation of C-H bonds. Differently structured ZnOx species supported on zeolites, SiO2, and Al2O3 have been reported to be active for nonoxidative dehydrogenation reactions. However, the structure-activity-selectivity relationships for these catalysts remain elusive. The main difficulty stems from the preparation of catalysts containing only one kind of well-defined ZnOx species.In this Account, we describe the studies on PDH and iBDH over differently structured ZnOx species and highlight our approaches to develop catalysts with controllable ZnOx speciation relevant to their performance. Several methods, including (i) the in situ reaction of gas-phase metallic Zn atoms with OH groups on the surface of supports, (ii) one-pot hydrothermal synthesis, and (iii) impregnation/anchoring methods, have been developed/used for the tailored preparation of supported ZnOx species. The first method allows precise control of the molecular structure of ZnOx through the nature of the defective OH groups on the supports. Using this method, a series of ZnOx species ranging from isolated, binuclear to nanosized ZnOx have been successfully generated on different SiO2-based or ZrO2-based supports as demonstrated by complementary ex/in situ characterization techniques. Based on kinetic studies and detailed characterization results, the intrinsic activity (Zn-related turnover frequency) of ZnOx was found to depend on its speciation. It increases with an increasing number of Zn atoms in a ZnmOn cluster from 1 to a few atoms (less than 10) and then decreases strongly for ZnOx nanoparticles. The latter promote the formation of undesired C1-C2 hydrocarbons and coke, resulting in lower propene selectivity in comparison with the catalysts containing only ZnOx species ranging from isolated to subnanometer ZnmOn clusters. In addition, the strategy for improving the thermal stability of ZnOx species and the consequences of mass-transport limitations for DH reactions were also elucidated. The results obtained allowed us to establish the fundamentals for the targeted preparation of well-structured ZnOx species and the relationships between their structures and the DH performance. This knowledge may inspire further studies in the field of C-H bond activation and other reactions, in which ZnOx species act as catalytically active sites or promoters, such as the dehydroaromatization of light alkanes and the hydrogenation of CO2 to methanol.

Crafting NaGd(MoO4)2 quadrilateral disks with oleic acid-assisted hydrothermal technique: Enhanced supercapacitor performance

Materials containing binary transition metals with MoO4 polyanions exhibit excellent stability, electrical storage capacity, long-term cycling resilience, and high operating voltage. In this study, an oleic acid-assisted hydrothermal synthesis method was used to control the morphology of NaGd(MoO4)2 quadrilateral disks (QuDs), and the electrodes based on the controlled morphology of NaGd(MoO4)2 QuDs were investigated for the fabrication of supercapacitors. In addition, cyclic voltammetry (CV) and constant current charge/discharge (GCD) analysis were performed to analyze the supercapacitance behavior of NaGd(MoO4)2 QuDs based electrode. The NaGd(MoO4)2 QuDs with 1.25 mL of oleic acid doped showed a good specific capacitance of ∼249.4 F∙g−1 at 0.01 V∙s−1 and excellent cycling stability, retaining up to ∼93.8% of its initial capacitance after 1000 cycles. Thus, the results indicate that the NaGd(MoO4)2 QuDs-based supercapacitor holds great potential as a high-performance option for advancing supercapacitor technology.

Highly Thermally Conductive Flexible Biomimetic APTES-BNNS/BC Nanocomposite Paper by Sol-Gel-Film Technology.

Owing to the evolution of 5G technology, new energy vehicles, flexible electronics, miniaturization and integration of microelectronic devices, high-frequency and high-power devices, and thermal management of materials must consider additional limitations such as electrical insulation, excellent transverse heat transfer, flexibility, and weight. Boron nitride nanosheets (BNNSs) are ideal insulating materials with high thermal conductivity. However, the problem of the 3D thermal conductivity pathway and toughness strength of nanocomposite paper loaded with inorganic thermal conductivity fillers remains a huge challenge. In this study, we propose a new method for preparing ultrathin, large, and uniformly thick BNNS for quantitative production. Bulk hexagonal boron nitride (hBN) layers were exfoliated using a simple and low-cost hydrothermal reaction, and large-scale fewer-layered BNNSs were efficiently prepared by ball milling with a high yield (up to 80%). Based on the aforementioned step, a flexible insulating composite film with high thermal conductivity and a natural "brick-mud" shell structure was constructed via the sol-gel-film conversion method. After prestretching and hot-pressing treatment, the hydrogels became denser, and the modified BNNS formed a three-dimensional (3D) network structure with an ordered orientation and interconnections in the bacterial cellulose (BC) matrix. After 100 folding cycles, the tensile strength of the nanofiber composite film reached 53 MPa, and the strength retention rate exceeded 42%. By optimizing the modified BNNS content, the thermal conductivity reached 24 W/(m·K). This simple approach has wide application potential in the next-generation electronic devices, providing options for designing thermal interface materials with excellent electrical insulation, high thermal stability, and flexibility.

Cs2NaGdCl6:Tb3+─A Highly Luminescent Rare-Earth Double Perovskite Scintillator for Low-Dose X-ray Detection and Imaging.

Rare-earth-based double perovskite (DP) X-ray scintillators have gained significant importance with low detection limits in medical imaging and radiation detection owing to their high light yield (LY) and remarkable spatial resolution. Herein, we report the synthesis of 3D double perovskite (DP) crystals, namely, Cs2NaGdCl6 and Tb3+-Cs2NaGdCl6 using hydrothermal reaction. Cs2NaGdCl6 DP single crystals exhibited a blue self-trapped exciton (STE) emission at 470 nm under ultraviolet (265 nm) excitation with a photoluminescence quantum yield (PLQY) of 8.4%. Introducing Tb3+ ions into Cs2NaGdCl6 has resulted in quenching of STE emission and enhancing green emission at 549 nm attributed to the 5D4 → 7F5 transition of Tb3+, suggesting efficient energy transfer (ET) from STE to Tb3+. This ET process is evidenced by the appearance of Tb3+ bands in the excitation spectra of the host, the shortening of the STE lifetimes in the presence of Tb3+ ions, and the enhancement of PLQY (72.6%). Furthermore, Cs2NaGdCl6:5%Tb3+ films of various thicknesses (0.1-0.6 mm) were synthesized and their X-ray scintillating performance has been examined. The Cs2NaGdCl6:5%Tb3+ film with 0.4 mm thickness has exhibited an excellent linear response to the X-ray dose rate with a low detection limit of 41.32 nGyair s-1, an LY of 39,100 photons MeV-1, and excellent radiation stability. Benefiting from the strong X-ray excited luminescence (XEL) of Cs2NaGdCl6:5%Tb3+, we developed a Cs2NaGdCl6:5%Tb3+ X-ray scintillator screen with a least thickness (0.1 mm), exhibiting remarkable imaging ability with a spatial resolution of 10.75 lp mm-1. These results suggest that Cs2NaGdCl6:Tb3+ can be a potential candidate for low-dose and X-ray imaging applications.

Aqua-Mediated Hydrothermal Synthesis in the Production of a g- C3N4/TiO2 Composite for Photocatalytic Degradation of RR4 Dye

Aqua-Mediated Hydrothermal Synthesis in the Production of a g- C3N4/TiO2 Composite for Photocatalytic Degradation of RR4 Dye

Zn-doped CdSSe composite quantum dots synthesized by a two-step hydrothermal ion exchange in sensitized solar cells

Metal ion doping is an effective strategy for enhancing the photoelectric properties of quantum dots (QDs). In this study, Zn-doped CdSSe composite QDs (ZnCdSSe) were synthesized using a two-step hydrothermal ion exchange method. The synthesis process involved the exchange reaction of Cd2+ with Zn2+, followed by the exchange reaction of Se2− with S2−, based on ZnS templates. The morphology, composition and crystalline phase of synthesized QDs were characterized using X-ray and electron-based techniques such as XRD, SEM, TEM, and XPS. The results indicate ZnCdSSe QDs were synthesized while preserving a similar morphology to that of ZnCdS. Performance tests demonstrated that quantum dot sensitized solar cells (QDSSCs) equipped with ZnCdSSe/TiO2 photoanodes achieved a power conversion efficiency (PCE) of 3.61% by optimizing the hydrothermal reaction temperature and time. This efficiency was 33.2% higher than that of CdSSe (2.17%) QDSSCs synthesized via a one-step hydrothermal exchange reaction using CdS templates. The significant enhancement in PCE can be attributed to improvements in light absorption and charge carrier transport. Notably, Zn doping reduced interface charge recombination and prolong electronic lifetime (τn), facilitating more effective charge collection in QDSSCs.