TiO2 Particles Research Articles

Preparation of TiO2 nanoparticles decorated porous carbon via a pseudo co-templating strategy and their application as substrates for high performance cathode of Li[sbnd]S batteries

Lithium‑sulfur batteries (LSBs) with a high theoretical specific capacity are considered as one of the most promising energy storage devices for next-generation. However, issues such as the insulation of pristine sulfur, the shuttle effect of polysulfides (LiPSs), and the volume change of sulfur cathode during cycling hinder their commercial applications. In this work, composite microspheres of TiO2@p-C consisting of porous carbon decorated with TiO2 nanoparticles, have been designed and synthesized aiming to confine and trap the polysulfides inside the porous substrates and to improve the kinetics of the electrochemical reaction therein. TiO2 particles with size of a few nanometers are prepared by a tetraethyl ammonium hydroxide assisted sol-gel method. Composite microspheres of TiO2@p-C are created through spray drying technique using chitosan as carbon source, and nanoparticles of SiO2 with TiO2 as co-template while selectively etching of the former. The confinement effects via the pores in the TiO2@p-C microspheres and the affinity between the polar TiO2 moieties and the polysulfide species work synergistically, alleviating the effusion of the polysulfides and promoting the conversion reaction of them as well. As a result, the shuttle effect of polysulfides can be inhibited obviously. Significantly, the S@TiO2@p-C-2 composite cathode exhibits excellent cyclic performance of 1263 mAh g−1 at 0.2C and maintains still a discharge capacity of 809 mAh g−1 after 100 charge and discharge cycles. At a current density of 2C, it still delivers an outstanding specific capacity of 772 mAh g−1. In the case of high sulfur load up to 90 wt%, the discharge capacity of S@TiO2@p-C-2 composite electrode could still maintain at 469.5 mAh g−1 after 100 cycles under current density of 0.2C.

Improvement of the microstructure and corrosion behavior of Ni-TiO2 composite coatings electrodeposited at various amounts of TiO2 powder

The purpose of this study was to produce efficient Ni-TiO2 composite coatings at different concentrations of TiO2 particles to enhance BS2 microstructure and corrosion resistance in 3.5 wt. % NaCl. % NaCl solution. EDS analysis shows that the Ti and O content increases by increasing the amount of TiO2. XRD results reveal that the preferential growth plane of pure Ni is (100), which corresponds to the (111) and (100) planes for Ni-TiO2 composite coatings. SEM shows that the substrates are coated homogeneously. In addition to the microstructural improvements, the corrosion resistance efficiency was enhanced significantly with the inclusion of TiO2 particles. Specifically, the study showed that 10 g/L of TiO2 provided the optimal balance, achieving a corrosion resistance efficiency of 74.6%, along with a marked reduction in porosity. Furthermore, the surface morphology confirmed a uniform and defect-free distribution of the TiO2 particles, contributing to the overall anti-corrosion properties. These findings suggest that Ni-TiO2 composite coatings are a promising candidate for industrial applications, particularly in environments where materials are exposed to harsh conditions, such as marine environments. The outcomes of this research have the potential to inform the development of advanced anti-corrosion strategies for various industries.

Size-dependent anatase to rutile phase transition under acoustic shocked conditions – A case study of TiO2 bulk and nanoparticles

In the present work, we attempt to explore the size-dependent structural stability of bulk (0.28 µm) and nano-sized (25 nm) anatase TiO2 particles under acoustic shocked conditions. Based on the observed X-ray diffractometric, Raman spectroscopic and transmission electron microscopic results with respect to the number of shock pulses, at the 90-shocked condition, the nano-size particles undergo the anatase to the rutile phase transition, whereas the bulk size TiO2 particles remain to be in the anatase phase. From the comprehensive assessment, it is demonstrated that the bulk TiO2 samples have higher structural stability compared to the nano-size samples. The nano-sized anatase-TiO2particles have values of lower thermal conductivity compared to the bulk-sized particles such that the value of lower thermal conductivity is a prominent crucial factor in initiating the dynamic recrystallization which results in the anatase-to-rutile phase transition. Based on the observed present experimental results and previous reports, it has been authenticated that, while increasing the particle size from nano-scale to micro-scale, the critical shock number for the anatase to rutile phase transition is significantly increased.

Spray-Deposited TiO2 Layers on Aluminum Foil for Sustainable Water Remediation

In this study, we developed TiO2-coated aluminum (TiO2/Al) surfaces using eco-friendly methods to create efficient and environmentally friendly photoactive materials with the potential to enhance water purification systems. TiO2 particles were deposited onto aluminum foil surfaces via a spray method, followed by heat treatment at 200 °C for 15 min. The morphology of the TiO2/Al surfaces, both before and after photocatalytic treatment, was characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The photocatalytic properties of these modified surfaces were evaluated through the degradation of rhodamine B (RB), methylene blue (MB), and methyl orange (MO) under simulated solar and UV–LED irradiation. Among the dyes tested, MO exhibited the highest degradation, influenced by factors such as absorption maximum, molecular structure, charge, and the number of condensed rings. The computational study of interactions between dye molecules and the combined nanoparticle revealed that the binding was the strongest in the case of MO dye. This study also explored the influence of varying the number of TiO2/Al surfaces in solution (one, five, and ten) on the photodegradation efficiency. The solution with five TiO2/Al surfaces demonstrated optimal performance, achieving a 16% degradation of RB. The reusability of the TiO2/Al surfaces was confirmed through five successive runs of RB degradation. The results indicate that TiO2/Al surfaces are a promising solution for addressing water contamination challenges and advancing sustainable water treatment practices.

Synthesis, characterization, and photocatalytic performance of gold ions implanted TiO2/graphene nanocomposites for efficient dye photodegradation

The suggested work provides a hydrothermal technique for the synthesis of TiO2/graphene nanocomposites with different weight percentages of graphene (0.0 %, 5.0 %, 10.0 %, and 15.0 %). These composites were implanted with gold ions at a fluence of 1 × 1013 ions/cm2 by using a pelletron accelerator. The structural and physical properties were investigated by utilizing XRD, FESEM, FTIR, EDX, and UV–Vis spectroscopy. The XRD data verified the existence of TiO2 with a rutile crystal phase. FESEM morphology showed that TiO2 particles had aggregated on graphene layers and had a semi-spherical shape. The functional groups present in the sample were identified using FTIR for TiO2 and TiO2/graphene nanocomposites. The stoichiometric ratios of all the constituent elements and the homogeneous composition were confirmed using EDX analysis. The UV–Vis spectroscopy revealed that the optical bandgap decreased from 3.15 eV to 2.80 eV. Additionally, the photocatalytic activity for the degradation of methylene blue (MB) under UV light was investigated. The photocatalytic performance was improved with increased graphene content. The evaluated data reveals that the sample with 10 % graphene has the maximum photocatalytic activity and rate constant. These findings suggest that gold-implanted TiO2/graphene nanocomposites favor photocatalytic applications and use in dye-sensitized solar cells.

Acidic phosphonium-based ionic liquid encapsulated on titania particles with enhanced electrorheological response

Research on electrorheological (ER) fluids has led to significant advancements in the development of smart materials that adjust their viscosity in response to applied electric fields. This study focused on synthesizing titania ionogel-based particles (TiO2-IL) using an environmentally friendly sol-gel process involving tetrabutoxy-titanium (TBT) combined with an ionic liquid (IL), specifically 11-carboxyundecyl-triphenyl-phosphonium bromide. The successful incorporation of the IL into the TiO2 particles was confirmed through thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and zeta potential analysis. The electrorheologial properties of TiO2-IL ionogel suspension in silicone oil were compared with those of pure TiO2 suspension. The addition of the ionic liquid (IL) significantly enhanced the electrorheological (ER) properties of the fluid, achieving a shear stress of approximately 1340Pa at an electric field strength of 5kV/mm. The fluid also exhibited excellent reversibility and a rapid response to changes in the electric field, which is attributed to the higher polarizability by the IL. Furthermore, the study observed low current density during operation, which helps maintain the fluid’s integrity and longevity under high electric fields. The fluids demonstrated stable ER effect across a temperature range of 40 to 70 ℃ and a reasonable sedimentation stability of around 80%. These characteristics, combined with the moderate conditions for particle preparation, make the TiO2-IL fluid a promising candidate for ER applications.

Porous TiO2 microspheres containing MgO nanoparticles/epoxy composite with superior thermal conductivity, EMI shielding, and electrical insulation

With the continuous advancement of electronic devices, the amounts of heat as well as electromagnetic (EM) waves generated have increased. Materials with high thermal conductivity and excellent EM interference shielding effectiveness (EMI SE) can be utilized to address this issue. In this work, we synthesized hollow anatase TiO2 microspheres. Through a reaction, MgO nanoparticles were incorporated into the interior of TiO2 microspheres. (H-TiO2/MgO). The heterostructure of the fillers contributed to performance enhancement. TiO2 and MgO particles formed a dual thermal-conduction pathway. H-TiO2/MgO effectively weakened the energy of EM waves upon contact. Additionally, TiO2, MgO, and epoxy all exhibited hydrophilicity. Consequently, the interfacial compatibility between H-TiO2/MgO and epoxy was excellent. They formed strong interfacial interactions by hydrogen bonding. Because of the excellent electrical insulation properties of H-TiO2 and MgO, the composites exhibited superior insulation performance (over 1010 Ω·cm). Our H-TiO2/MgO/Epoxy composites exhibited a maximum thermal conductivity of 7.52 W/m·K, an EMI SE of 64.92 dB, and a tensile strength of 79.10 MPa. Our composites are expected to effectively manage heat and EM waves generated by electronic devices

A UV-resistant porous composite film for radiative cooling and enhanced hydrophobicity

Passive Daytime Radiative Cooling (PDRC) offers a promising strategy to reduce surface heat by reflecting solar radiation and emitting long-wave infrared radiation into space. However, the widespread application of PDRC is currently limited by challenges such as complex fabrication processes, high costs, and the materials’ susceptibility to outdoor aging. In this work, we fabricated a cost-effective, ultraviolet (UV)-resistant porous composite (UPC) film by phase separation technology. UPC films achieve high solar reflectance (0.92) and outstanding broadband longwave infrared thermal emissivity (0.975) by adjusting particle size and mass fractions of TiO2 particles embedded in Poly (methyl methacrylate) (PMMA). When applied to a drone, the films achieve a cooling effect of 12.6°C. Notably, the mid-infrared emissivity of UPC films remained stable after prolonged exposure to UV radiation (360 hours at an irradiance of 1 W/m2), with the reflectance decreasing by only 1.3 %. Software simulations were employed to evaluate the energy savings performance of UPC films in various urban environments, showing significant energy-saving benefits. Furthermore, after treatment with the modified solution, the surface contact angle of UPC films reaches 152.5°, providing excellent resistance to contamination. This work contributes to the advancement of low-cost, durable, and energy-efficient cooling solutions.

Oxidation mechanism and kinetics of TiB2 submicron powders in air

AbstractHigh‐activity TiB2 submicron powders were synthesized via microwave‐assisted carbothermal reduction, and their oxidation behavior at 550°C–1000°C for 0.5–1.5 h in air atmosphere was carried out by the isothermal oxidation test. The phase composition and microstructure evolution of the oxidation products were performed by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). It was established that TiB2 submicron powders had been significantly oxidized at 550°C, and the oxidation products were TiO2 and B2O3. Hexagonal plate‐like TiB2 grains had been completely disappeared, and fragmented into uniform nano‐scale spherical TiO2 particles after being oxidized at 1000°C for 1 h, accompanied by the violent evaporation of B2O3 products at temperatures above 1000°C. In addition, the corresponding oxidation kinetics was investigated by using a non‐isothermal thermogravimetric (TG)–differential scanning calorimetry (DSC) technique. The results showed that the Mample power law (n = 1) was the most probable mechanism function, and the oxidation activation energy E of TiB2 submicron powders was 640.58 kJ/mol.

Research of two kinds of PANI@semiconductor based photocathodic coating corrosion protection effect and mechanism

PurposeThis study aims to report the development and experimental evaluation of two kinds of PANI@semiconductor based photocathodic anti-corrosion coating, for application on stainless steel substrates.Design/methodology/approachPANI was in situ chemical polymerized on TiO2 and BiVO4 particles, and FT-IR and SEM/EDS were used to understand the characteristics and elemental distribution of the composite particles. Composite coatings, which consisted of epoxy, PANI@TiO2 or PANI@BiVO4 and graphene, were prepared on the 304L stainless steel. Photoelectrochemical response measurement, electrochemical tests and immersion tests were used to assess the anti-corrosion performance of the prepared coatings in 45°C 3.5 wt.% NaCl solution. And the corrosion protection mechanism was further explained by combining with surface observation.FindingsThe photoelectrochemical response tests revealed the good photocathodic effect of the coatings, and the reversible oxidation-reduction properties of PANI (pseudocapacitive effect) leading to the repeated usage of the coatings. Consequently, the anti-corrosion mechanism of the composite coating is attributed to the physical barrier effect of the coating, the anodic protection effect of PANI and the photocathodic and energy store effect.Originality/valueThese kind coatings could prevent corrosion from day to night for stainless steel, which has great engineering application prospects on stainless steel corrosion protection.

Coating of Refractory Surfaces with Fine TiO2 Particles via Gas-Dynamic Cold Spraying

Refractory materials are used worldwide in process equipment. However, gaseous and liquid process products penetrate the surface layer and deep into the volume of refractories, destroying rather expensive constructions that are complicated to repair. To address this challenge, there is a need to develop protective coatings for refractory materials that can limit the penetration of working media and extend their operational lifespan. In this work, the application of gas-dynamic cold spraying (CGDS) to produce a coating on the refractory materials using fine titanium dioxide (TiO2) particles is explored. These particles are accelerated within a nitrogen flow, passing through a Laval nozzle, and then sprayed onto a fireclay surface. The mechanisms of particle deposition and layer formation on porous surfaces through experiments and numerical simulations were investigated. The geometry of a typical refractory pore was determined, which was then incorporated into computational fluid dynamics (CFD) simulations to model the cold spraying process of porous substrates. As a result, the influence of the particle size on its velocity and angle of penetration into pores was established. Experimental findings demonstrate the effective closure of pores and the formation of a particle layer on the refractory surface. Furthermore, the nanoindentation tests for the refractory samples showcase capabilities for checking coating thickness for porous materials.

P19-31 Comaparison of TiO2 particle size distribution in artificial digestion solutions using single-particle ICP-MS

P19-31 Comaparison of TiO2 particle size distribution in artificial digestion solutions using single-particle ICP-MS

Effect of titanium dioxide nanoparticles on the dielectric, thermal, and corrosion resistance properties of polyimide (PI) nanocomposites

In the present study, the effect of varying titanium dioxide (TiO2) nanoparticles on the dielectric, thermal, and corrosion characteristics of PI-based composites prepared by spark plasma sintering was investigated. The results obtained revealed that the TiO2 nanoparticles were uniformly dispersed within the PI matrix. Addition of TiO2 into the neat PI markedly reduced its dielectric constant and electrical conductivity by 72.7% and 82.3%, respectively, as well as enhancing its breakdown strength by 16.7% at 8 wt% TiO2 loading. The nanocomposites depict better thermal stability and heat-resistance index characteristics when compared to the PI. Additionally, the produced nanocomposites exhibit improved corrosion resistance than that of the neat PI. The remarkable improvement in the dielectric, thermal stability, and corrosion resistance of the nanocomposites is achieved by better dispersion of the TiO2 particles in the polymer matrix. The enhancement in properties suggests TiO2/PI-based nanocomposites potential for a variety of applications in electrical insulation, thermal management, and harsh environment.

Pd Catalysts Supported on Mixed Iron and Titanium Oxides in Phenylacetylene Hydrogenation: Effect of TiO2 Content in Magnetic Support Material.

Recently, Pd catalysts supported on magnetic nanoparticles (MNPs) have attracted a great attention due to their ability of easy separation with an external magnet. Modification of MNPs is successfully used to obtain Pd magnetic catalysts with enhanced catalytic activity. In this work, we discussed the effect of titania content in TiO2/MNPs support materials on catalytic properties of Pd@TiO2/MNPs catalysts in phenylacetylene hydrogenation. TiO2/MNPs composites were prepared by simple ultrasound-assisted mixing of TiO2 and MNPs, synthesized by co-precipitation method. This was followed by deposition of palladium ions on the mixed metal oxides using NaOH as precipitant. The supports and catalysts were characterized using XRD, BET, STEM, EDX, XPS, and a SQUID magnetometer. Pd nanoparticles (5-6 nm) formed were found to be homogeneously distributed on support materials representing the well-mixed metal oxides with TiO2 content of 10, 30, 50, or 70%wt. Testing of the catalysts in phenylacetylene hydrogenation showed that their activity increased with increasing TiO2 content, and the process was faster in alkali medium (pH = 10). The hydrogenation rates of triple and double C-C bonds on Pd@70TiO2/MNPs achieved 9.3 × 10-6 mol/s and 23.1 × 10-6 mol/s, respectively, and selectivity to styrene was 96%. The catalyst can be easily recovered with an external magnet and reused for 12 runs without significant degradation in the catalytic activity. The improved catalytic properties of Pd@70TiO2/MNPs can be explained by the fact that the surface of the support is mainly composed of TiO2 particles, affecting the state and size of Pd species.

Fluorescent, multifunctional anti-counterfeiting, fast response electrophoretic display based on TiO2/CsPbBr3 composite particles

Traditional optical anti-counterfeiting (AC) is achieved by static printed images, which makes them susceptible to lower levels of security and easier replication. Therefore, it is essential to develop AC device with dynamic modulation for higher security. Electrophoretic display (EPD) has the advantages of low power consumption, high ambient contrast ratio, and capability of showing dynamic images which is suitable for dynamic AC applications. Herein, we prepared a dynamical AC device based on a fluorescent EPD, and achieving the image switch between black, white, and green fluorescence states under the dual-mode driving (electronic field and UV light). We loaded perovskite quantum dots (CsPbBr3) onto the TiO2 particles and further prepared fluorescent electrophoretic particles TiO2/CsPbBr3-3-PLMA (TiO/CPB-3) by grafting and polymerizing method. In addition, we fabricated the AC devices based on the fluorescent EPD, which exhibits the multifunctional AC, where the fluorescent EPD has a fast response time of 350 ms, a high contrast ratio of 17, and bright green fluorescence. This prototype demonstrates a new way for future dynamic AC and identification.

Piezoelectric assisted boosting photocatalytic hydrogen evolution over a finely prepared Pt/TiO2/g-C3N4 composite system using lactic acid as sacrificial agent

A one-step calcination method was employed to fabricate a new TiO2/g-C3N4(TCN) composite catalyst. The therein TiO2 nanoparticles with good dispersion were synthesized through a sol-gel method and followed by additional heat treatment. The ultra-thin and flat g-C3N4(CN) nanosheets were synthesized by calcining a mixture of urea and melamine. The obtained TCN exhibited significantly excellent performance, especially when 3 wt% Pt was added and lactic acid (HL) was used as a sacrificial agent, achieving a rate of 32.5 mmol/h/g. This improvement can be attributed to the uniform dispersion of nano TiO2 particles on g-C3N4, the flat ultra-thin layer structure of CN, and the constructed heterojunctions between two, which promote the separation of photogenerated electron-hole pairs. Measurements of PL and photocurrent response confirmed enhanced efficiency in interface charge separation and transfer. Additionally, it demonstrated lower internal resistance in EIS tests. Notably, owing to the piezoelectric properties of CN, when the reaction liquid was subjected to additional ultrasonic treatment, the hydrogen production rate further increased to 43.57 mmol/h/g and 2.9 mmol/h/g, respectively, in simulated sunlight and visible light response. The piezoelectric effect of CN induced by ultrasound regulated the bandgap width of the catalysts, broadening their response to visible light.

Study on the Relationship between Electron Transfer and Electrical Properties of XLPE/Modification SR under Polarity Reversal.

The insulation of high-voltage direct-current (HVDC) cables experiences a short period of voltage polarity reversal when the power flow is adjusted, leading to sever field distortion in this situation. Consequently, improving the insulation performance of the composite insulation structure in these cables has become an urgent challenge. In this paper, SiC-SR (silicone rubber) and TiO2-SR nanocomposites were chosen for fabricating HVDC cable accessories. These nanocomposites were prepared using the solution blending method, and an electro-acoustic pulse (PEA) space charge test platform was established to explore the electron transfer mechanism. The space charge characteristics and field strength distribution of a double-layer dielectric composed of cross-linked polyethylene (XLPE) and nano-composite SR at different concentrations were studied during voltage polarity reversal. Additionally, a self-built breakdown platform for flake samples was established to explore the effect of the nanoparticle doping concentration on the breakdown field strength of double-layer composite media under polarity reversal. Therefore, a correlation was established between the micro electron transfer process and the macro electrical properties of polymers (XLPE/SR). The results show that optimal concentrations of nano-SiC and TiO2 particles introduce deep traps in the SR matrix, significantly inhibiting charge accumulation and electric field distortion at the interface, thereby effectively improving the dielectric strength of the double-layer polymers (XLPE/SR).

Thin-shelled hollow mesoporous TiO2 spheres with less tortuosity as fast-charging anode

TiO2 is a stable and abundantly available material that is a promising alternative to graphite anodes. However, compact stacking of TiO6 octahedra induces repulsion between the inserted Li ions, reducing rate performance and achievable capacity. Herein, we propose mesoporous hollow TiO2 spheres composed of nanosized anatase to mitigate these issues. The hollow structure allows for ion transport both inward and outward. The empty-core material is obtained by depositing sub-20 nm TiO2 particles synthesized through the sol–gel process onto a carbon nanosphere support, followed by scaffold elimination. Thin TiO2 shells facilitate ion migration via a reduced tortuosity with minimizing isolated pore formation, allowing DLi+ of 3.22 × 10−11 cm2 s−1 to be attained, which is 40 times higher than that of bulk-type TiO2. The facile Li-ion transport enables the insertion of 0.66 mol Li ions per mol of TiO2 at 0.5C and 67 % rate performance (10C vs. 0.5C). The designed hollow TiO2 exhibits stable capacity retention of 85.9 % for 1000 cycles at a fast charging rate of 20C. A full cell with a LiFePO4 cathode exhibits 60 % rate capability (2000 vs. 50 mA g−1). Thin mesoporous hollow TiO2 facilitates the Li-ion transport and enable fast charging, confirming the potential of this anode for fast-charging applications.

Electrodeposited Ni-Fe-TiO2 Alloy Composites for the Hydrogen Evolution Reaction

Hydrogen is a carbon-free alternative energy source that is environmentally friendly, has high energy density, and is a promising fuel for future generations. Water splitting is an efficient way to produce hydrogen, requiring a catalyst with a small overpotential and Tafel slope, and good stability. However, only 4 % of global hydrogen is produced by water electrolysis due to high cost and lack of inexpensive replacements of the active platinum electrocatalyst.1 However, replacing these noble metal electrocatalysts with those comprised of lower, earth-abundant elements remains challenging as these materials impart a higher overpotential and thus require higher energy. Guided by the recognised enhancements of TiO2 particles in Co-Mo alloys for HER, earth-abundant, low-cost Ni and Fe metals are examined as composite electrocatalysts Ni-Fe-TiO2 towards HER.2 Nano-scale TiO2 particles were embedded into Ni-Fe alloys by using galvanic and pulse-reverse electrodeposition, onto rotating cylinder electrodes. Pulse-reverse electrodeposition considerably increased the concentration of the particles incorporated into the alloy. The composition and morphology were characterized by X-ray fluorescence (XRF) spectroscopy and scanning electron microscopy (SEM), respectively. The addition of particles to the electrolyte affected both the deposit composition and morphology. The alloy composites were then used as electrocatalysts in 1 M KOH to characterize HER via linear sweep voltammetry on the resulting hydroxide surface. The surface area was examined in a ferri/ferrocyanide electrolyte. The polarization data in 1 M KOH shows a significant reduction in the HER overpotential when TiO2 particles are present in the Ni-Fe deposit. The surface analysis of Ni-Fe and Ni-Fe-TiO2 confirmed that the improvement in HER activity is not due to surface roughness but an intrinsic one. The stability of the electrocatalysts under an electrolysis for HER was examined at -10 mA/cm2 for 24 hr and the working electrode potential remained stable over time; Tafel polarization curves after electrolysis were similar to those prior to electrolysis. References Le, P. A., Trung, V. D., Nguyen, P. L., Phung, T. V. B., Natsuki, J., & Natsuki, T. RSC advances, 13(40), 28262-28287 (2023).C. Wang, H. K. Bilan, and E. J. Podlaha. J. Electrochem. Soc. 166 F661 (2019). C. Wang and E. J. Podlaha, J. Electrochem. Soc. 167, 132502 (1~4) (2020).

Radiation and nanoparticle interaction for enhanced light absorption and heat conversion

The photo-thermal conversion performance (PTCP) of water-based nanofluids in a volumetrically heated solar collector (VHSC) is evaluated. The influences of nanoparticle volume concentration (NVC), particle size, Reynolds number, operating temperature, and collector geometry on the PTCP are numerically investigated. The utilization of nanoparticles and improving their concentration is found to enhance the photo-thermal conversion efficiency (PTCE) of the collector by augmenting the energy from the sun of the working fluid due to the radiation-nanoparticle interactions. The PTCE enhancement of Graphite, TiO2 and Ag nanoparticles dispersed in water is respectively 1.37, 1.33 and 1.29 times better, compared to that of water. This is further augmented by adding MgO nanoparticles to TiO2, Graphite and Ag particles, resulting in 1.69, 1.67 and 1.59x improved efficiency. Enhancing the flow rate of the fluids also contributes to the PTCE by reducing the losses of thermal from the collector to the ambient. Besides, the enhanced nanoparticle size increases the overall PTCP as it enables the nanofluid to absorb more solar energy. Enhancing the collector length accelerates the thermal loss to the ambient, as a result the system performance diminishes. It is also regarded that the heat absorption of the nanofluid declines with improving inlet temperature of the working fluid.