Reduction-precipitation Method Research Articles

“Synthesis and characterization of TiO2 nanoparticles as brake fluid additives: Viscosity modulation and impact on rheological properties”

TiO2 nanoparticles were synthesized using the reduction precipitation method, verified by powder x-ray diffraction (PXRD) with an average crystallite size of 62 nm and an average particle size of 135 nm from SEM images. Rheological studies of brake fluid with nanoparticle additives revealed that while the fluid generally maintains consistent behavior, a 2 wt.% concentration showed non-Newtonian behavior at 120 °C. Viscosity increased slightly with nanoparticle addition and decreased with rising temperature, with the 0.5 wt.% sample demonstrating the most notable increase of 18.18% at 120 °C. At 30 °C, the 1 wt.% sample exhibited a 4.06% increase. The observed viscosity changes are attributed to higher internal shear stress and the need to manage dispersion solid elements. The Herschel-Bulkley model was effective in predicting sample behavior, and all samples conformed to Reynolds’ equation μ 0 = b e − aT . This research indicates that TiO2 nanoparticles can be effectively used as brake fluid additives, offering potential benefits for high-temperature applications in vehicles. Further optimization using mathematical models such as response surface methodology (RSM) is suggested for improved performance.

Comprehensive recovery of valuable elements from vanadium precipitation liquor using selective impurity removal-reduction precipitation process

The vanadium precipitation liquor produced by the vanadium slag extraction process contains various valuable elements, which are not utilized at high value. In this paper, chromium is recovered through aluminum salt impurity removal - chemical reduction precipitation method. Moreover, the ammonia nitrogen and sodium sulfur in the vanadium precipitation liquor are recovered by stripping and crystallization, thereby achieving comprehensive resource recovery and utilization. The aluminum salt slag removal reduction chemical precipitation method is used to separate Cr from Si, Ca and V impurities. As a result, the obtained Cr2O3 product has a purity of 98.20%, the chromium recovery efficiency is 97.58%, and the silicon removal efficiency reaches 99.66%. The ammonia nitrogen was recovered by stripping, which would be reused to the vanadium precipitation process, with an ammonia nitrogen stripping efficiency of 98%. The purity of NH4Cl is 99.13% and meets the 99-level national standard. The Na2SO4 was recovered by evaporation concentration - crystallization method, which would be reused to the vanadium slag roasting process, with a Na2SO4 recovery efficiency of 88.38%. And the purity of Na2SO4 is 98.85%, which meets the industrial standard for Class II Na2SO4 products. The final solution after comprehensive recovery of valuable elements would be reused to the leaching process, thereby achieving water circulation. This process realizes the high-value utilization of chromium, ammonia, nitrogen, sodium and sulfur, and has no wastewater discharge and is an environment-friendly route.

Manipulating the electronic state of ruthenium to boost highly selective electrooxidation of ethylene to ethylene glycol in acid

Electrochemical oxidation of ethylene is a novel approach to manufacture valuable ethylene glycol (EG), which is an important raw material in organic chemical industry. However, the poor EG selectivity and expensive additional purification costs hinder this method from being practically used. In this work, ultrafine iridium-ruthenium (IrRu) alloy nanoparticles are synthesized through the precipitation-reduction method and their electrocatalytic performance towards ethylene oxidation to EG has been comprehensively studied. Near 100% selectivity is achieved with a EG yield of 60.62 mmol gRu−1 h−1 at 1.475 V on an optimal Ir0.54Ru0.46 catalyst. OH-stripping, in-situ electrochemical attenuated total internal reflectance Fourier transform infrared spectra and DFT calculation reveal that the introduction of Ir can modulate the electronic structure and d-band center so as to endow the Ru with the mild binding energy with the key intermediates and small energy barrier for *HOCH2CH2OH desorption, thereby enhancing the EG generation. Simultaneously, the high energy barrier for the overoxidation of the *CH2CH2OH renders the EG formation thermodynamically favorable, thus realizing the near 100% EG selectivity. This work provides a new understanding for the high-selectivity electrosynthesis of high-value-added oxides.

Palladium doped with boron and phosphorus on activated carbon: a high-performance nanocatalyst for the hydrogenation of alkenes

Fabrication of high-performance palladium on activated carbon (Pd/AC) nanocatalysts for hydrogenation of alkenes to reduce the cost of reaction products has always been of interest to researchers and industries. Herein, the purpose was the step-by-step investigation of the simple precipitation-reduction method to determine the best chemicals usable in producing the high-performance 10%Pd/AC nanocatalyst for the hydrogenation of alkenes. Hence, different types of carbon supports, alkaline agents, and reducing agents were selected for this purpose. Catalytic hydrogenation of cinnamic acid to hydrocinnamic acid was used as a well-known standard test for evaluating the activity of the nanocatalysts. The AC prepared by pine wood, H2PdCl4, KHCO3, and NaBH4/NaH2PO2 were the most suitable materials for producing high-performance Pd/AC using the mentioned method. It was specified that activity is increased with the lower amount of oxygenated acidic functional groups on the AC, greater cation radius of the alkaline agent, weaker alkaline agent, and higher reduction power of the reducing agent. NaH2PO2 and especially NaBH4 increase the activity more than other reducing agents because of their high reduction power and adding phosphorus (P) and boron (B) to Pd, respectively. Three nanocatalysts with the most activity were chosen for more investigations by different analyses. The results of these analyses were according to the procedure obtained for their catalytic activity. The reusability test of chosen nanocatalysts indicated that the stability of Pd/AC is increased by doping the Pd with B and especially P. According to the obtained results, Pd nanocatalyst doped with both P and B is strongly recommended for application in alkenes hydrogenation.

Novel 3D Cu2O/N-CQD/ZIF-8 composite photocatalyst with Z-scheme heterojunction for the efficient photocatalytic reduction of Cr(Ⅵ)

ZIF-8 exhibits poor visible light response and rapid electron-hole recombination. To address these problems, we constructed an N-CQD/ZIF-8 framework by in-situ synthesis method, then prepared a novel Z-scheme heterostructure photocatalyst (Cu2O/N-CQD/ZIF-8) by reduction precipitation method for the efficient photocatalytic reduction of Cr(Ⅵ). Cu2O/N-CQD/ZIF-8 (with a 10% Cu2O loading) had a unique heterostructure and exhibited significantly improved performance for Cr(Ⅵ) photoreduction. This photocatalyst successfully reduced 98.99% of the Cr(Ⅵ) in a pH = 3 solution system, which was 6 times higher than that of ZIF-8. Meantime, due to its stable interfacial adhesion, the reduction efficiency of Cr(Ⅵ) by Cu2O/N-CQD/ZIF-8 still reached 97.13% after five cycles. Therefore, Cu2O/N-CQD/ZIF-8 exhibited superior photocatalytic activity and recyclability compared with unmodified ZIF-8. The charge transfer path of this Z-scheme heterojunction was verified by free radical trapping experiments and X-ray photoelectron spectroscopy. Moreover, a possible charge transfer mechanism was proposed. N-CQD provided a potential driving force for the construction of the internal Z-scheme charge transfer system. Moreover, the synergistic effect between Cu2O and ZIF-8 inhibited the rapid recombination of photogenerated electron-hole pairs. This work provides potential insights for the innovative design of high-performance photocatalysts based on metal-organic frameworks for the restoration of Cr(Ⅵ)-containing wastewater.

Enhanced Performance of nZVI/MXene@CNTs for Rapid As(III) Removal from Aqueous Solutions

Transition metal compounds demonstrated good performance in the removal of environmentally harmful contaminants, such as arsenic, while the aggregation propensity and poor chemical stability should be noticed. In this study, the nZVI/MXene@CNTs was adequately prepared by liquid reduction precipitation method for adsorption and oxidation of As(III) from the aqueous solution. The results of batch removal experiments showed that the maximum removal capacity of the nZVI/MXene@CNTs for As(III) was 443.32 mg/g with the pH = 3.0 at 25 °C. The effects of initial pH, dosage of materials and ionic strength on As(III) removal were explored. According to the various characterization analyses, the most plausible mechanisms of As(III) removal were the surface complexation, solid phase precipitation and the catalytic oxidation by the •OH. Furthermore, the nZVI/MXene@CNTs could be readily activated and reused via leaching with 0.1 M NaOH solution, due to the three-dimensional mesh intercalation structure. Therefore, it is a potential nanocomplex for removing and recovering As(III) from water with excellent capacity and environmental friendliness.

Fast and efficient single step synthesis of modified magnetic nanocatalyst for catalytic reduction of 4-nitrophenol

In this work, asparagine chitosan magnetic nanoparticles (ACMNPs) have been synthesized in single step using reduction-precipitation method. The synthesized nanoparticles were characterized using FTIR, SEM, HR-TEM, EDX, TGA, VSM, XRD and UV–Vis techniques. The shape of nanoparticles found was spherical as well as semi-spherical and the size obtained through HRTEM was 6.0–7.5 nm. EDX analysis showed the presence of elements such as carbon, nitrogen, oxygen, iron which confirmed the modification. The magnetic nanoparticles were found to be sufficiently magnetic as saturated magnetization value obtained with the help of VSM was 19.4 emu/g. The synthesized nanoparticles were applied for catalytic reduction of a toxic organic pollutant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) which has industrial and medical application. 4-Nitrophenol converted to 4-nitrophenolate ion in presence of NaBH4 as reducing agent. On addition of ACMNPs nanocatalyst the 4-nitophenolate quickly converted to 4-aminophenol as confirmed by the color change from yellow to colorless in few minutes. The effect of parameters like amount of catalyst (10–25 mg) and temperature (25–55 °C) on time of catalysis were also evaluated. The results obtained showed that increasing both the amount of catalyst and temperature enhanced the catalysis rate. Increasing the amount of catalyst from 10 to 25 mg reduces the time of catalysis from 18 min to 6 min, while increasing the temperature from 25 °C −55 °C, reduces the catalytic time from 9 min to 4 min with 20 mg of nanocatalyst. The rate constant K1 and activation energy obtained were 0.4681 min−1 and 24.03 kJ mol−1 respectively. Furthermore, the reusability of nanocatalyst was also studied and it was found that easy separation of magnetic nanocatalyst with the help of external magnet enhanced its reusability and the catalyst showed good reusability of up to 3 cycles.

CO2 hydrogenation to light olefins over mixed Fe-Co-K-Al oxides catalysts prepared via precipitation and reduction methods

A series of Fe-Co-K-Al oxides catalysts were prepared by precipitation-reduction method using NH4OH as precipitating agent and NaBH4 as reducing agent. The effect of preparation methods including one-pot preparation (C1), without the addition of NH4OH (C2), precipitation followed by reduction (C3) and doubling NaBH4 content of C3 (C4) on the physicochemical properties of the catalysts as well as their catalytic CO2 hydrogenation to light olefins was investigated. The preparation methods had a significant influence on phase, reducibility and the amount and strength of CO2 and H2 adsorption with the catalysts surface. The structure–activity relationships indicated that the CO2 conversion was proportional to the amount of medium CO2 adsorption sites, while the O/P ratio increased with decreasing the amount of weak H2 adsorption sites. The C3 catalyst exhibited the highest light olefins yield of 16.58% at 350 °C and 20 bar. This was attributed to a significant reduction of weak adsorption of H2, while maintaining a high level of medium CO2 adsorption, inhibiting the hydrogenation of olefins to paraffins products and providing the relatively high CO2 conversion, respectively. Replacing the reducing gas from H2 to a gas mixture containing H2 and CO2 of the C3 catalyst (C5) was unable to reduce the iron species to metallic Fe, resulting in the formation of Fe3C which was less active for the production of hydrocarbon compared to Fe5C2 phase formed in the C3 catalyst.

Diatomite supported nano zero valent iron with 3D network for peroxymonosulfate activation in efficient degradation of bisphenol A

• Diatomite and nZVI was effectively assembled to activate peroxymonosulfate. • nZVI/diatomite (NDA) catalyst is endowed with complex network structure. • Unique pore structure improves the activation properties of materials. • Both free radical and non-free radical pathways charged for degrading BPA. Diatomite supported nano zero valent iron (nZVI) catalyst (NDA) with complex network structure was prepared via a mild reduction precipitation method in this work. The pore structure and pore distribution of NDA can be regulated and controlled through adjusting the loading amount of nZVI. In general, the nano three-dimensional network formed by nZVI and diatomite channels greatly increase the specific surface area and pore volume of NDA, and further formed more active sites, which made NDA have better performance in activating PMS to degrade BPA than pure nZVI. The pseudo-first-order reaction rate constant of 50-NDA (50%-nZVI/diatomite) is almost 3 times higher than that of pure nZVI. Besides, the electron paramagnetic resonance (EPR) and radical quenching experiments showed that the activation process was dominated by the sulfate radical (SO 4 ·− ) and hydroxyl radical ( · OH) produced by Fe 0 oxidation. The generated electrons promote the self-decomposition of PMS to produce singlet oxygen ( 1 O 2 ), and then the valence state of iron changes to produce free radicals. In addition, the possible degradation pathway of BPA was inferred from the intermediate products identified by liquid chromatograph-mass spectrometer (LC-MS). This study provides a novel strategy for the design and preparation of three-dimensional composite catalysts derived from natural mineral.

Fast electron transfer and enhanced visible light photocatalytic activity of silver and Ag2O co-doped titanium dioxide with the doping of electron mediator for removing gaseous toluene

Volatile organic compounds (VOCs) can influence air quality and threaten human health; however, the development of an effective method to remediate toxic VOCs is still remain challenge. Herein, a novel silver and Ag2O co-doped TiO2 with fast electron transfer modified by nitrogen doping carbon dots was prepared via a facile chemical precipitation-reduction method. Under 50 min of visible light irradiation, the novel photocatalyst exhibited approximately 50% gaseous toluene degradation efficiency, which was ca. 9.7 times and 2.2 times higher than that of bare TiO2 and silver and Ag2O co-doped TiO2, respectively. Importantly, the photocatalyst also showed a stable structure and good recycling ability after 400 min of photocatalytic degradation with little amount of NCDs. Besides, the up-conversion effect of NCDs could emit high-energetic light and thus generate more e−-h+ pairs, which could facilitate the SPR effect of Ag and thus showed strong visible light response because of the localized surface plasmon resonance (LSPR) excitation. Thus, the excellent photocatalytic performance could attribute to the synergetic effect of up-conversion effect of NCDs and SPR effect of silver which could both facilitate charge carriers separation and improve visible-light response. Finally, a possible mechanism for the excellent photocatalytic activity was proposed, in which the active species including ·O2−, ·OH and h+ were generated and contributed to photocatalytic process. The successful fabrication of DACT provides a potential strategy for the treatment of VOCs in practical applications.

Optimized Pt-MnOx interface in Pt-MnOx/3DOM-Al2O3 catalysts for enhancing catalytic soot combustion

The catalysts of three-dimensionally ordered macroporous (3DOM) Al2O3-supported core-shell structured Pt@MnOx nanoparticles (3DOM-Pt@MnOx/Al2O3) were successfully prepared by the gas bubbling-assisted membrane reduction-precipitation (GBMR/P) method. Pt@MnOx core-shell nanoparticles (NPs) are highly dispersed on the inner surface of 3DOM-Al2O3 support. Pt@MnOx/3DOM-Al2O3 catalysts, which combine both advantages of high-efficiency soot-catalyst contact by 3DOM-Al2O3 structure and the abundant active sites by the optimized Pt-MnOx interface, exhibit high catalytic activities for soot combustion, and the catalytic activities are strongly dependent on the thickness of MnOx shell. Among the catalysts, 3DOM-Pt@MnOx/Al2O3-1 catalyst with optimized Pt-MnOx interface shows the highest catalytic activity for soot combustion, i.e., its values of T50 and SCO2m are 351 °C and 98.6%, respectively. The highest density of Pt-MnOx active sites for adsorption-activation of gaseous O2 is responsible for enhancing catalytic activity for soot combustion. Pt@MnOx/3DOM-Al2O3 catalysts are promising to practical applications for the emission reduction of soot particles.

A facile synthesis of Ag/Ag2O@TiO2 for toluene degradation under UV–visible light: Effect of Ag formation by partial reduction of Ag2O on photocatalyst stability

In recent years, environmental pollution caused by volatile organic compounds (VOCs) has posed a great challenge to environmental protection. This first-attempt study provided a novel facile chemical precipitation-reduction method to construct Ag/Ag2O@TiO2 (A/AO@TO) photocatalyst for the removal of gaseous toluene. The introduction of Ag in the presence of NaBH4 with N2 purging inhibited the passivation of Ag2O and thus enhanced the stability of A/AO@TO. A/AO@TO exhibited outstanding photocatalytic performance toward gaseous toluene under different light sources like UV light, simulated sunlight and natural light, which were 99.3%, 48.3% and 28.5%, respectively. The superior photocatalytic performance could be attributed to the synergy effect of p-n heterojunction between Ag2O and TiO2 and the surface plasmon resonance (SPR) effect of Ag, which facilitate the separation of charge carriers and thus suppress the recombination rate of them, and enhance the light response. The active species like ·OH, ·O2− and h+ were contributed to the excellent photocatalytic performance. The study provided a new method for the fabrication of A/AO@TO photocatalyst and introduce p-n scheme A/AO@TO as a feasible natural sunlight photocatalyst for further applications.

Chitosan-Grafted Halloysite Nanotubes-Fe3O4 Composite for Laccase-Immobilization and Sulfamethoxazole-Degradation.

A surface-engineered nano-support for enzyme laccase-immobilization was designed by grafting the surface of halloysite nanotubes (HNTs) with Fe3O4 nanoparticles and chitosan. Herein, HNTs were magnetized (HNTs-M) by a cost-effective reduction-precipitation method. The synthesized HNTs-M were grafted with 0.25%, 0.5%, 1%, and 2% chitosan (HNTs-M-chitosan), respectively. Synthesized HNTs-M-chitosan (0.25%), HNTs-M-chitosan (0.5%), HNTs-M-chitosan (1%) and HNTs-M-chitosan (2%) were linked with glutaraldehyde (GTA) for laccase immobilization. Among these formulations, HNTs-M-chitosan (1%) exhibited the highest laccase immobilization with 95.13% activity recovery and 100.12 mg/g of laccase loading. The optimized material was characterized thoroughly by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM) analysis. The immobilized laccase (HNTs-M-chitosan (1%)-GTA-Laccase) exhibited higher pH, temperature, and storage stabilities. The HNTs-M-chitosan (1%)-GTA-Laccase possesses excellent reusability capabilities. At the end of 10 cycles of the reusability experiment, HNTs-M-chitosan (1%)-GTA-Laccase retained 59.88% of its initial activity. The immobilized laccase was utilized for redox-mediated degradation of sulfamethoxazole (SMX), resulting in 41%, 59%, and 62% degradation of SMX in the presence of 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), guaiacol (GUA), and syringaldehyde (SA), respectively. Repeated SMX degradation (57.10% after the sixth cycle) confirmed the potential of HNTs-M-chitosan (1%)-GTA-Laccase for environmental pollutant degradation. Thus, we successfully designed chitosan-based, rapidly separable super-magnetic nanotubes for efficacious enhancement of laccase biocatalysis, which can be applied as nano-supports for other enzymes.

Adjustable n-p-n gas sensor response of Fe3O4-HNTs doped Pd nanocomposites for hydrogen sensors

The Fe3O4-HNTs doped Pd nanocomposites were synthesized by the reduction-precipitation method. The surface modification by Pd is utilized to enhance the selectivity of the Fe3O4-HNTs doped Pd nanocomposites. The sensor shows the normal n-type response to other interfering gases; however, it shows a concentration-dependent n-p-n transition for its gas sensor response towards H2. This unusual sensing characteristic can be described by the formation of n-Fe3O4-HNTs/p-Fe-O-Pd/n-Fe3O4 HNTs heterojunction structures. This type of gas sensors can be utilized in highly ultra-sensitive and selective H2 sensing and this work also opens up a facile way for tailoring the selectivity of gas sensors by the surface modification.

Surface tuning of halloysite nanotubes with Fe3O4 and 3-D MnO2 nanoflakes for highly selective and sensitive acetone gas sensing

Nanosized M-HNTs-MnO2 (Magnetic halloysite nanotubes-manganese dioxide) nanocomposite was synthesized by the reduction-precipitation method followed by the hydrothermal process. The existence of MnO2 nanoflakes on M-HNTs represents 3-D nanostructures without stacking of nanotubes and agglomeration. The sensor-based on M-HNTs-MnO2 nanocomposites exhibits higher sensor response (Rair/Rgas = 35.6) to 100 ppm of acetone gas at operating temperature (150 °C), with a short response-recovery time (3 s/7 s). The M-HNTs-MnO2 nanocomposite sensor shows excellent potential to act as a low cost, low-temperature sensor for acetone gas, with high acetone selectivity under high humidity conditions and with the interference of other gases. The high surface to volume ratio, three-dimensional nanostructure, and strong interactions between M-HNTs and MnO2 nanoflakes are accountable for the improvement of acetone sensing performance. Based on the high acetone selectivity, high stability and fast dynamic response, the M-HNTs and MnO2 sensor is an extremely appropriate candidate for a low-cost acetone sensor, and the projected approach offers a way to develop gas sensors that can be function at low temperatures for a wide variety of applications.

Photo-electrochemical hydrogen evolution over FTO/Ni0.98Si0.02O2-Ni electrode induced by visible and UV light irradiation

Photo-electrochemical properties of fluorine-doped tin oxide (FTO)/nickel oxide-nickel (Ni0.98Si0.02O2-Ni) with isolated Si sites are discussed. The Ni0.98Si0.02O2-Ni photo-electrocatalyst without any noble metal was prepared using a one-step chemical reduction precipitation method. Photo-electrochemical properties were investigated by cyclic voltammetry and chronoamperometry techniques in aqueous alkaline solution at pH 8.0. The photo-electrochemical response of the catalyst showed sensitivity to visible and UV light. The catalyst produced hydrogen from water at a rate of 0.5 mmol g−1 h−1 with the reduction of CO2 into CO under visible light in the absence of any light sensitizer or a noble metal. The metallic Ni amount in the catalyst system was optimized to obtain the best photo-electrocatalyst. The first principle DFT study showed that the incorporation of Si sites allowed absorbance of visible light. The catalyst was characterized by powder x-ray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma- atomic emission spectroscopy (ICP-AES), Brunauer–Emmett–Teller (BET), cyclic voltammetry, and chronoamperometry. The products were analyzed by gas chromatography- thermal conductivity detector (GC-TCD).

One‐step synthesized magnetic MIL‐101(Cr) for effective extraction of triazine herbicides from rice prior to determination by liquid chromatography‐tandem mass spectrometry

The magnetic metal-organic framework MIL-101(Cr) material-based solid-phase extraction method coupled with high-performance liquid chromatography and tandem mass spectrometry was applied to extract seven triazine herbicides in rices. Fe3 O4 /MIL-101(Cr) was synthesized using reduction-precipitation method, in which steps including pre-synthesis and modification of Fe3 O4 nanoparticles were by-passed. Various parameters including extraction solvent type and volume, ultrasonic extraction time, amount of Fe3 O4 /MIL-101(Cr) microspheres, adsorption time, desorption volume and time were investigated. Under optimal conditions, the proposed method had the limit of detection (S/N=3) and the limit of quantification (S/N=10) of 1.08-18.10 and 3.60-60.20 pg/g, respectively. Relative standard deviations calculated for all herbicides with concentrations of 2 and 20ng/g were in the range of 0.5 to 13% (n=3). In addition, at the two above-mentioned concentrations, the method achieved relative recoveries percentages of 79.3 to 116.7% when applied to determine the triazine herbicides in real samples spiked. This rapid, green, non-polluting, pre-concentrated extraction method was successfully developed and applied to analyze herbicides in rice samples.

Rapid precipitation-reduction synthesis of carbon-supported silver for efficient oxygen reduction reaction in alkaline solution

Silver has emerged as a promising electrocatalyst for oxygen reduction reaction (ORR) in alkaline membrane fuel cell for its high stability in alkaline solution. However, the electrocatalytic activity of silver-based ORR electrocatalyst is generally poor. This paper presents a rapid precipitation-reduction method to synthesize carbon-supported silver electrocatalysts, which involves precipitating AgBr compound on carbon support, and then transforming it into carbon-supported silver via an in situ electrochemical reduction process. The obtained electrocatalysts show excellent oxygen reduction performances in terms of E½ (0.84 V vs. RHE) and mass specific activity Jm (9.1 mA mgAg−1@0.85 V), outperforming most of recent reported silver-based ORR electrocatalysts. Further experiment indicates that the improved electrocatalytic performances can be assigned to the presence of lattice defects at Ag surface, which can facilitate the adsorption and further reduction of oxygen molecular on the silver surface.

SPIONs Prepared in Air through Improved Synthesis Methodology: The Influence of γ-Fe2O3/Fe3O4 Ratio and Coating Composition on Magnetic Properties.

Superparamagnetic iron oxide nanoparticles (SPIONs) have shown great potential in biomedicine due to their high intrinsic magnetization behaviour. These are small particles of magnetite or maghemite, and when coated, their surface oxidation is prevented, their aggregation tendency is reduced, their dispersity is improved, and the stability and blood circulation time are increased, which are mandatory requirements in biomedical applications. In this work, SPIONs were synthesized in air through a reduction-precipitation method and coated with four different polymers (Polyethylene glycol(PEG) 1000/6000 and dextran T10/T70). All the synthesized samples were structurally and magnetically characterized by transmission electron microscopy, Fourier transform infra-red spectroscopy, X-ray powder diffraction, Mössbauer spectroscopy, and Superconducting Quantum Interference Device (SQUID) magnetometry. SPIONs centrifuged and dried in vacuum with an average diameter of at least 7.5 nm and a composition ≤60% of maghemite and ≥40% of magnetite showed the best magnetization results, namely a saturation magnetization of ~64 emu/g at 300 K, similar to the best reported values for SPIONs prepared in controlled atmosphere. As far as SPIONs’ coatings are concerned, during their preparation procedure, surface polymers must be introduced after the SPIONs’ precipitation. Furthermore, polymers with shorter chains do not affect the SPIONs’ magnetization performance, although longer chain polymers significantly decrease the coated particle magnetization values, which is undesirable.

Facile synthesis of BiCuOS for photocatalytic application

An aqueous reduction-precipitation method was reported for the synthesis of BiCuOS nanoparticles with size of several hundred nanometers. The reaction was performed under low temperature by reducing thiourea-copper complex to [Cu2S2]2−, followed by precipitation with [Bi2O2]2+. The as-synthesized BiCuOS exhibited full spectrum absorption properties and excellent visible-light induced photocatalytic activity. This study reveals that BiCuOS is a promising candidate for photocatalytic application.