Low-cost Deposition Research Articles

CuBi2O4/CuO photocathode with conformal CQD@Ni(OH)2 coating for stable solar water splitting

CuBi2O4 exhibits a high onset potential and theoretically high photocurrent density due to its well-matched bandgap for solar water splitting. However, factors such as low charge carrier mobility and severe charge recombination prevent CuBi2O4 from reaching its ideal photoelectrochemical performance, while photocorrosion of the Cu element severely compromises its stability. Herein, a convenient and low-cost chemical bath deposition method has been employed to combine carbon quantum dots (CQDs) with Ni(OH)2, resulting in the preparation of a conformal CQD@Ni(OH)2 layer-coated CuBi₂O₄/CuO heterojunction photocathode. Under AM 1.5G illumination, CuBi2O4/CuO/CQD@Ni(OH)2 illustrates a photocurrent density of −1.36 mA cm−2, which is 2.12 times higher than that of CuBi2O4/CuO. More importantly, the conformal coating of CQD@Ni(OH)2 effectively prevents photocorrosion induced by oxidation-reduction reactions of Cu2+/Cu. At 0.3 VRHE, the photocurrent of CuBi2O4/CuO/CQD@Ni(OH)2 remains at 76.4% after 10000 s of chopped light illumination, significantly outperforming the 48.9% retention observed for CuBi2O4/CuO photocathode after 3600 s of chopped light illumination. This work demonstrates that the CQDs and Ni(OH)2 are good candidates for the photoelectrode overlayer with significant synergetic effects.

Evaluation of mechanical and microstructural characteristics in different regions of wire arc additive manufactured 304L austenitic stainless steel

ABSTRACT The large structural components (304 L austenitic stainless steel) used in nuclear power plants are difficult and expensive to manufacture and machine using standard methods. Wire arc additive manufacturing (WAAM) is a low cost and high deposition method for fabricating large structural parts. Therefore, in this investigation, 304 L austenitic stainless steel (304 L ASS) cylindrical component was fabricated using WAAM technique. The mechanical and microstructural characteristics of the bottom (region ①) and top (region ②) of the WAAM 304 L ASS component are studied. The microstructure of region ① consists of austenite and ferrite with vermicular and lathy morphologies, while region ② consists of skeletal and reticular morphologies. In regions ① and ②, yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) were found to be 350 ± 7 MPa, 562 ± 10 MPa, and 75 ± 1%, respectively. The impact toughness and hardness in regions ① and ② were found to be 112 ± 2 J and 183 ± 6 (Hv0.5), respectively. From the results, it is evident that the tensile properties of the WAAM 304 L ASS component were equal/greater than the values of the forged 304 L ASS material, wrought 304 L ASS alloy, and 304 L ASS filler wire.

Producing Freestanding Single-Crystal BaTiO3 Films through Full-Solution Deposition.

Strontium aluminate, with suitable lattice parameters and environmentally friendly water solubility, has been strongly sought for use as a sacrificial layer in the preparation of freestanding perovskite oxide thin films in recent years. However, due to this material's inherent water solubility, the methods used for the preparation of epitaxial films have mainly been limited to high-vacuum techniques, which greatly limits these films' development. In this study, we prepared freestanding single-crystal perovskite oxide thin films on strontium aluminate using a simple, easy-to-develop, and low-cost chemical full-solution deposition technique. We demonstrate that a reasonable choice of solvent molecules can effectively reduce the damage to the strontium aluminate layer, allowing successful epitaxy of perovskite oxide thin films, such as 2-methoxyethanol and acetic acid. Molecular dynamics simulations further demonstrated that this is because of their stronger adsorption capacity on the strontium aluminate surface, which enables them to form an effective protective layer to inhibit the hydration reaction of strontium aluminate. Moreover, the freestanding film can still maintain stable ferroelectricity after release from the substrate, which provides an idea for the development of single-crystal perovskite oxide films and creates an opportunity for their development in the field of flexible electronic devices.

Low-cost deposition of tunable band gap Zn(O,S) as electron transport layer for crystalline silicon heterojunction solar cells

In recent years, the research on silicon heterojunction (HJT) solar cells based on dopant-free contacts has experienced rapid development. Zn(O,S) is a low work function n-type semiconductor compound with tunable band gap that can be used as the electron transport layer (ETL) in HJT solar cells. In our work, we choose Zn(O,S) as ETL and deposit it via the low-cost chemical bath deposition (CBD) method. Uniform and fast growth of Zn(O,S) films can be obtained by regulating the concentration of the complexing agent and the ratio of reactants to reduce the generation of impurities. To further achieve band matching with c-Si, the Zn(O,S) films are processed with air-annealing to modify the elemental ratios. The air-annealing lowers the interfacial electron transport barrier, which promotes charge separation and transport, thus reducing carrier recombination at the interface. Finally, the PCE of HJT solar cell based on CBD-Zn(O,S) ETL is close to 15 %, providing a new potential route for the development of low-cost HJT solar cells.

Analysis of carbon and nitrogen from atmospheric sources by bulk deposition sampling at various locations in Germany

Atmospheric deposition of particulate matter is an important indicator of air pollution and a significant factor in material surface fouling. The elemental composition of this nutrient-containing dust depends largely on the exposure region and time as well as on climate. Therefore, in this paper we report an analysis of atmospheric pollutions with a self-made low-cost bulk deposition sampler directed at sampling deposition via air transport and rainfall. We used the device in diverse environments - thus comparing an urban region, an area surrounded by forest and an area mainly dominated by agriculture. The total organic carbon (TOC) and total nitrogen (TN) amounts were selected as indicator parameters and analyzed in a biweekly rhythm for three and a half and two years, respectively. The TOC value responded to particulate matter in the urban area, especially significant were the influences of the New Year's firework in urban and pollen in the rural forest area. In contrast, the TN value was more under the influence of the nitrogen emissions in the agriculture-dominated area. However, the TN value did not correlate with the NOx values in the urban area because the atmospheric nitrogen emissions in the city might originate from various emission sources. Summarizing, the TOC and TN values of the self-made low-cost bulk deposition sampler were in good agreement with environmental events of their immediate surrounding. Moreover, the selected containers and sampling procedures are universally applicable to monitor and analyze organic as well as inorganic parameters (e.g. metal ions) of atmospheric deposition.

Chemical bath deposition of SnO2 films on PEN/ITO substrates for efficient flexible perovskite solar cells

Flexible perovskite solar cells (f-PSCs) have achieved significant success. However, high-quality tin dioxide (SnO2) electron transport layers (ETLs) fabricated via chemical bath deposition (CBD) have not been achieved on flexible PEN/ITO substrates. This limitation is primarily due to the corrosion of the poor-quality ITO layer by the strongly acidic CBD solution. Here, we analyzed the reasons for the poor corrosion resistance of ITO films on PEN substrate from multiple perspectives, such as element composition, microstructure, and crystallinity. Then, we proposed a modified CBD method for SnO2 films suitable for flexible PEN/ITO substrates. We employed SnCl2·2H2O as the tin source and regulated the pH of the CBD solution by NH3·H2O, which effectively avoided the corrosion of the ITO layer by the CBD solution and achieved high-quality SnO2 films on the ITO layers. Compared to the commercial SnO2 dispersion, the SnO2 films prepared by this method have smaller grains and higher transmittance. As a result, we achieved an unprecedented power conversion efficiency (PCE) of 20.71% for f-PSCs fabricated on PEN/ITO substrates with SnO2 ETLs by CBD method. This breakthrough facilitates the development of high-performance f-PSCs by a low-cost and large-scale chemical bath deposition of high-quality ETLs on flexible substrates.

Impact of Cu2+ precursor on physical and photoelectrochemical properties of electrodeposited nanostructured CuS thin films for biosensor applications

Nanostructured CuS films were synthesized on FTO substrates employing low-cost electro deposition technique. XRD, Raman, SEM, UV–visible spectroscopy, photocurrent, PL, Mott-Schottky, and electrochemical impedance spectroscopy (EIS) measurements were used to examine physical and photoelectrochemical properties of samples. XRD results indicated that CuS films have hexagonal crystal structure where the crystallite size raises from 32 to 53 nm with increasing the Cu2+ molarity. Raman results displayed two peaks at 270 and 450 cm−1 that related to A1g transverse optical mode (TO) and A1g longitudinal optical (LO) mode for the vibrations of the S–S stretching and Cu–S bonds, respectively. SEM images displayed that fabricated CuS cover the substrate surface entirely, where grains are distributed uniformly with increasing the Cu+2 molarity. UV–visible measurements exhibited an absorption band edge between 450 and 550 nm as a characteristic of CuS films direct band gap. PL results presented strong blue-green emission at about 500 nm for CuS thin films. The photocurrent studies demonstrated that the CuS films are p-type semiconductors where the current density increases from 0.8 mA/cm2 to 1.1 mA/cm2 with the Cu2+ molarity increasing. The EIS analysis confirmed that charge transfer resistance reduces with increasing molarity. Mott- Schottky measurements established that carrier concentrations and the flat band varied from 5 × 1019 to 6.7 × 1019 cm−3 and from 1.1 to 0.75V, respectively. The fabricated CuS film was tested as glucose biosensor where a fast response and higher stability were noticed. Our results indicated that nanostructured CuS films are gifted candidates for optoelectronics applications especially biosensors.

Aminated reduced graphene oxide-carbon nanotube composite gas sensors for ammonia recognition

Composites based on carbon nanomaterials exhibit many advantageous properties for gas sensing, such as high and fast response, room-temperature operation, and tailoring sensitivity by energy level engineering. However, only the first attempts to employ such chemosensors for gas-sensing applications have been made. In this work, an on-chip multisensor array of carboxylated carbon nanotubes (CNT), aminated reduced graphene oxide (rGO-Am), and CNT/rGO-Am nanocomposite was fabricated using a simple and low-cost spray deposition method. The CNT/rGO-Am sensor demonstrated a fast and high response to NH3 in dry air at low (25 ppm) and high (400 ppm) concentrations of 70 and 115 %, respectively. The response to NH3 in humid air increased and reached 160 % at 400 ppm. The chemosensor exhibited high sensitivity and selectivity toward ammonia with a low detection limit estimated to be below 0.2 ppb. Linear discriminant analysis of the sensor responses to different concentrations of NH3, dry and humid air revealed better discrimination when CNT/rGO-Am composites were used in combination with CNT and rGO-Am sensors in an array. This study demonstrates that composite sensors with junctions between carbon nanomaterials have great potential for practical applications in fast and selective gas detection at room temperature and different humidity.

Microstructural characteristics and properties of wire arc additive manufactured 304L austenitic stainless steel cylindrical components by different arc welding processes

Wire arc additive manufacturing (WAAM) is an advanced additive manufacturing (AM) technology that offers low cost and high deposition rates, making it suitable for building large metal parts for structural engineering applications. However, various welding procedures result in differing heat inputs and repetitive heating treatments throughout the deposition process, which can affect the microstructural and mechanical characteristics of the parts. In the current study, cylindrical parts made of 304L austenitic stainless steel (ASS) were manufactured using the WAAM technique, employing both gas metal arc welding (GMAW) and cold metal transfer (CMT) processes. This study explores the correlation between WAAM techniques and their effects on the bead geometry, microstructure and mechanical properties. The microstructure of the cylinders consisted of vertically growing austenite dendrites with residual ferrite (δ) within the austenite (γ) matrix. Compared to the bottom region (region ①), the top region (region ②) contained more residual ferrite. Although the microstructural characteristics from region ① to region ② are similar, they exhibit different ferrite morphologies. The rapid cooling rate in the CMT-AM process resulted in finer structures and a greater presence of ferrite phases in both regions compared to the GMAW-AM method. Cylinders produced by the CMT process displayed nearly uniform properties across both regions and demonstrated superior tensile properties, hardness, and impact toughness relative to those made using the GMAW technique. The WAAM 304L ASS cylinders also showed enhanced performance compared to stainless steel manufactured using traditional industrial forging standards, indicating that WAAM-processed 304L ASS cylinders are suitable for industrial applications.

Ultradurable Embedded Physically Unclonable Functions.

Physically unclonable functions (PUFs) have attracted growing interest for anticounterfeiting and authentication applications. The practical applications require durable PUFs made of robust materials. This study reports a practical strategy to generate extremely robust PUFs by embedding random features onto a substrate. The chaotic and low-cost electrohydrodynamic deposition process generates random polymeric features over a negative-tone photoresist film. These polymer features function as a conformal photomask, which protects the underlying photoresist from UV light, thereby enabling the generation of randomly positioned holes. Dry plasma etching of the substrate and removal of the photoresist result in the transfer of random features to the underlying silicon substrate. The matching of binary keys and features via different algorithms facilitates authentication of features. The embedded PUFs exhibit extreme levels of thermal (∼1000 °C) and mechanical stability that exceed the state of the art. The strength of this strategy emerges from the PUF generation directly on the substrate of interest, with stability that approaches the intrinsic properties of the underlying material. Benefiting from the materials and processes widely used in the semiconductor industry, this strategy shows strong promise for anticounterfeiting and device security applications.

Construction of branched SnS2/Te heterostructure film for self-powered high-performance photodetector application

Effective design and construction of heterostructure can conduce to charges transportation/separation and simultaneously improve light absorption ability of photoelectrochemical (PEC) photoelectrode. In this work, the p-type Te nanorods were directly grown on the surface of ultra-thin SnS2 nanoflakes via a facile and low-cost electrochemical deposition (ED) method. The PEC performance of mixed-dimensional branched SnS2/Te nanoflakes/nanorods (NFRs) heterostructure composites film was optimized by varying the ED time. Under simulated light illumination of 40 mW/cm2, the optimal photocurrent density of the SnS2/Te NFRs photoanode significantly reached up to 0.95 mA/cm2, approximately 5.2 times and 3.5 times larger than those of bare SnS2 and Te film, respectively. The improved performance was attributed to appropriate energy band matching and intensive light absorption property. In particular, it presented good stability and high light on/off ratio of about 4.1 ×106 at the 0 bias voltages, suggesting an excellent self-powered characteristic of the device. Furthermore, the SnS2/Te NFRs photodetector exhibited photoresponsivity of 127 mA/W at 0.8 V bias and photodetectivity of 1.33 ×1011 Jones, respectively. This study presents a rational strategy to improve the photodetection performance of SnS2-based PEC-type photodetector and opens a new avenue for designing high-efficiency photoelectronics device.

Modification of microstructure and mechanical properties for twin-wire directed energy deposition-arc fabricated Ti–48Al–2Cr–2Nb alloys via current regulation

Considering the advantages of low density and excellent high-temperature performance, titanium aluminide is identified as an ideal aerospace structural material. In recent years, twin-wire directed energy deposition-arc (TW-DED-arc), which possesses the characteristics of low cost but high deposition efficiency, has continuously attracted worldwide attention. However, obtaining equiaxed grains with small Al variation for titanium aluminide using TW-DED-arc method is still a key concern. In the present research, Ti–48Al–2Cr–2Nb alloy with equiaxed lamellar colonies and less than 1 at.% of Al content was successfully fabricated by regulating deposition current of TW-DED-arc. Also, the effect of deposition current on microstructure and mechanical properties was systematically investigated. The experimental results that focus on top and middle regions of as-fabricated TiAl-4822 alloys, indicate that increasing current favors in generation of equiaxed grains and γ lamellae, which leads to columnar to equiaxed transition and higher γ phase content, respectively. Also, elemental homogeneity can be significantly homogenized. As deposition current increases, tensile strength increases while degree of tensile anisotropy decreases significantly, benefiting from the equiaxed grains with satisfying size. Importantly, microstructure evolution, tensile anisotropy and fracture characteristics of TW-DED-arc fabricated TiAl-4822 alloys are discussed in detail. Generally, these findings provide an effective process method to optimize microstructure and mechanical properties of TW-DED-arc fabricated TiAl-4822 alloys.

Transparent-to-Brown-Black Patterned Electrochromic Metal-Organic Frameworks.

Metal-organic frameworks (MOFs) exhibit promising electrochromic (EC) performance owing to their porous structure, regular channel, and tunable component characteristics. However, few reports focus on MOF materials with the EC performance of a transparent to brown-black (neutral colored state) change that is more suitable for smart windows. In this work, we proposed a strategy for synthesizing MOF (named Ni-BPY) EC materials and corresponding films fabricated via a low-cost electrostatic spray deposition technique. The obtained film exhibits excellent EC performance with a neutral color change from transparent to brown-black, a large optical modulation of 70% at 430 nm, and a fast response within 10 s. Benefiting from good electrical and chemical stability, the Ni-BPY film can be cycled over 500 times. Notably, the Ni-BPY MOF film also delivers a stepwise-controlled process during the bleached state due to its porous characteristics. In addition, the unique color variation of the Ni-BPY film derives from the redox reaction of the Ni metal node between Ni2+ and Ni3+, which is verified by the in situ potential-dependent Raman and X-ray photoelectron spectroscopy (XPS) measurement. As a proof of application, the patterned Ni-BPY EC films and devices are additionally constructed to demonstrate their potential application in electronic tags and logo displays.

Multiscale Electrical Response Assessment of Metal Nanowire Transparent Electrodes: A Computational Strategy

Transparent electrodes made of random distributions of metal nanowires (NWs) are appealing for optoelectronic devices, solar cells, light emitting diodes, and transparent heaters. While these electrodes are comparable to thin films in terms of electrical conductivity and transparency, their network structure allows limiting the amount of conductive material and makes them suitable for low-cost solution-based deposition methods, contributing to an overall costs reduction. Despite these advantages, an even material utilization at different length scales is difficult to achieve. The homogeneous distribution of electric current (electrical homogeneity) is indeed not guaranteed in nanowire electrodes but is crucial for the stability of the electrode and actually desirable in most applications. Despite the relevance of this feature, it is common practice to perform qualitative assessments at the electrode scale, overlooking local effects. To address this issue, we have developed a computational strategy to aid in the design of nanowire electrodes with improved electrical homogeneity.We present a computational approach that allows an objective, quantitative, and systematic assessment of the electrical homogeneity. The approach enables a multiscale comparison of electrodes with different NW content and material properties. Nanowire electrodes are modeled as two-dimensional networks of stick and junction resistors (with resistance Rw and Rj, respectively) to simulate the electric conduction process. Electrodes are discretized into regular grids of squares and the electrical power of the network contained in each square is computed. The mismatch between the areal power density of the entire electrode and that of the squares provides a quantitative electrical homogeneity evaluation. Repeating the analysis with squares of different size yields an evaluation that spans across length scales. A scalar indicator, coined the homogeneity index, summarizes the results of the multiscale evaluation.Parametric studies are performed by varying nanowire content and nanowire-to-junction resistance ratio Rw/Rj. We show that electrical homogeneity improves as i) NW density increases, and ii) junction resistance reduces. The ideal condition of negligible junction resistance (Rw >> Rj) leads to the best-case scenario and guarantees the highest rate of improvement of electrical homogeneity with NW content. Nevertheless, we observe that under condition Rw ≈ Rj the response of the system approaches the response of a system meeting the ideal condition Rw >> Rj (15% difference at most in terms of homogeneity index). We therefore conclude that reducing the junction resistance excessively (with the aim of achieving Rw/Rj > 1) may not always be a worthwhile strategy, as it results in only a marginal improvement in terms of electrical homogeneity.The proposed strategy is employed to assess the electrical homogeneity of silver nanowire electrodes through the analysis of scanning electron microscopy images. Our results agree with the outcomes of the experimental assessment performed on the same electrodes.

Ga-polar GaN Camel diode enabled by a low-cost Mg-diffusion process

In this letter, we show that low-cost physical vapor deposition of Mg followed by a thermal diffusion annealing process increases the effective barrier height at the metal/Ga-polar GaN Schottky interface. Thus, for the first time, GaN Camel diodes with improved barrier height and turn-on voltage were realized compared to regular GaN Schottky barrier diodes. Temperature-dependent current–voltage characteristics indicated a near-homogeneous and near-ideal behavior of the GaN Camel diode. The analysis performed in this work is thought to be promising for improving the performance of future GaN-based unipolar diodes.

Study on PECVD-hetero-grown β-Ga2O3 thin film and temperature-modulated solar-blind UV photodetection

Using a convenient and low-cost plasma-enhanced chemical vapor deposition technique, uniform Ga2O3 thin films were hetero-grown on c-plane sapphire substrates at different temperatures, with a root mean square roughness as low as 2.71 nm and a growth rate of up to 1121.30 nm h−1; and then the solar-blind UV photodetection performances were discussed in detail. Metal-semiconductor-metal solar-blind UV photodetectors (PDs) based on the five Ga2O3 films prepared at different temperatures exhibit ultra-low dark currents (I dark) ranging among 22–168 fA. Under the illumination of 254 nm UV light, the PD prepared by the film grown at 820 °C possesses the highest performance, with a high photo-to-dark current ratio of 1.47 × 105, a low rise/decay time of 0.067/0.13 s, a specific detectivity (D *) of 3.56 × 1012 Jones, and a linear dynamic range of 92.89 dB. Overall, the results in this work may well provide a referable method for growing cost-effective and ultralow-noise Ga2O3 thin films, as well as achieving decent solar-blind UV sensing applications.

Indium-zinc-oxide thin films produced by low-cost chemical solution deposition: Tuning the microstructure, optical and electrical properties with the processing conditions

Indium-zinc-oxide (IZO) films were prepared by spin coating an ethanol-ethylene-glycol precursor solution with a Zn/(In + Zn) ratio of 0.36 on glass. The effects of temperature on the structure, microstructure, electrical, and optical properties of the IZO thin films were investigated by thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, electron and atomic-force microscopy, X-ray photoelectron spectroscopy and variable-angle spectroscopic ellipsometry. The prepared IZO thin films heated at 500, 600, and 700 °C in air were transparent, without long-range ordering, and with an RMS surface roughness of less than 1 nm. The lowest electrical resistivity at room temperature, 0.0069 Ωcm, was observed for the 115-nm-thick IZO thin film heated at 600 °C in air and subsequently post-annealed in Ar/H2. The thin film exhibited a microstructure characterized by grains typically 20 nm in size and had no organic residues. This film exhibits uniaxial optical anisotropy due to its ultra-thin lamellae with a high electron density. The ordinary refractive index was fitted as a Tauc-Lorentz-Urbach function, which is typical of an indirect absorption edge occurring in amorphous semiconductor materials. The principal absorption peak with an onset at about 2.8 eV and a Tauc gap energy of ∼2.6 eV is similar to those observed for In2O3. The described process of chemical solution deposition and subsequent curing is promising for the low-cost fabrication of IZO thin films for transparent electronics, and can be used to tune the structure and microstructure of IZO thin films, as well as their electrical and optical properties.

Trash to treasure: Transforming wasted polystyrene foam to conductive fibers by polymer pyrolysis deposition on glass fibers

Recycling and utilization of waste polymers is an important part of the sustainable development of fossil resources. In this work, carbon-coated glass fibers (CGFs) with high electrical conductivity were prepared through a low-cost polymer pyrolysis deposition (PPD) method by using waste polystyrene foam as carbon source. The CGFs exhibited an electrical conductivity of up to 615 S/m and the conductivity of carbon coating layer reached to 5.5 × 104 S/m. The electrical conductivity was related to the mass ratio and graphitization of the carbon layer, and the C–Si bonds provide a tight connection between the carbon layer and the glass fibers. Overall, this work found a way for transforming waste polymers to conductive fibers and this strategy would not only lower the cost of conductive fibers but also solve reutilization of the white pollution.

The Effect of substrate Nature on the properties of Tin Sulfide Nanostructured films Prepared by chemical bath deposition

The substrate's nature plays an important role in the characteristics of semiconductor films because of the thermal and lattice mismatching between the film and the substrate. In this study, tin sulfide (SnS) nanostructured thin films were grown on different substrates (polyester, glass, and silicon) using a simple and low-cost chemical bath deposition technique. The structural, morphological, and optical properties of the grown thin films were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. The XRD and FESEM results of the prepared films revealed that each film is polycrystalline and exhibits both orthorhombic and cubic structure types. In addition, the deposited films on polyester and glass showed good absorption in the UV-Vis-NIR range.

Tin Oxide Nanoparticles via Solar Vapor Deposition for Hexavalent Chromium Remediation.

Tin oxide nanoparticles optimized to capture low concentrations of hexavalent chromium from water were developed through a facile, scalable, and low-cost one-step solar vapor deposition methodology. Considering the preservation of high electron donation capacity as the key to support the reduction of mobile Cr(VI) into insoluble forms, the growth of SnO nanoparticles was favored by the co-evaporation of SnO2 with Fe powders at various mass ratios. Characterization techniques indicated that the percentage and the stability of SnO is proportional to the Fe content in the target with a requirement of at least 50% wt to inhibit the formation of a passive SnO2 surface layer. The produced particles were evaluated regarding their efficiency to capture Cr(VI) under conditions similar to water treatment for drinking purposes (pH 7). It was revealed that passivation-free SnO nanoparticles deliver significant improvement in the adsorption capacity corresponding to the residual concentration of 25 μg/L, reaching a value of 1.74 mg/g for the sample prepared with 50% wt Fe in the target. The increase of water acidity was found responsible for the activation of more reduction sites on the particle surface, as reflected through the elevation of efficiency by more than 20% at pH 6.