Chemical Etching Approach Research Articles

Material synthesis, crystal structure, Hirshfeld surface and physicochemical characteristics Novel Stilbazolium crystal of 4-(2-(3-ethoxy-4-hydroxy-phenyl)-vinyl)-1-methyl pyridinium iodide (MEMPI) single crystal for NLO activity

In this study, a novel cation donor group 3-ethoxy-4-hydroxy benzaldehyde has been incorporated in the Stilbazolium cation with iodide anion to generate a new NLO activity of a single crystal of 4-(2-(3-ethoxy-4-hydroxy-phenyl)-vinyl)-1-methyl pyridinium iodide (MEMPI). The MEMPI crystal was effectively formed via the solvent evaporation technique. The structure and hydrogen bond interactions found in the molecule were determined by employing single-crystal X-ray diffraction. The compound crystallizes in the space group P21/c and monoclinic crystal pattern. The crystal structures are stabilized via intramolecular, intermolecular hydrogen bond interactions, C‒H···π, cation‒π, anion‒π, π···π stacking and lone pair-π interaction. In addition, a variety of O‒H···O, O‒H···I and C‒H···O interactions are also responsible for crystal packing. The 3D Hirshfeld surface and 2D fingerprint plots were used to examine the nature of intermolecular interaction. The 2D fingerprint maps indicate that the interactions between H···H contribute to 48.9 % of the total crystal stability. The newly synthesized material was characterized by 1H NMR and 13C NMR. In addition, the vibrational study of the synthesized molecule was performed using FTIR analysis. The grown crystal in linear optical characteristics were examined via a UV–Visible-NIR study. The photoluminescence (PL) activity of a MEMPI was studied with respect to the visible area and green colour emission was observed at 536 nm. The estimated CIE coordinates on the RGB colour gamut show the MEMPI crystal's ability to emit green light. The chemical etching approach was used to analyse the etch pit density and the growth habitat of the MEMPI crystal. The closed and open aperture Z-scan tests were carried out to determine the nature of third-order NLO susceptibility of the MEMPI crystal.

MXene Synthesis and Carbon Capture Applications: Mini-Review.

MXenes, a class of two-dimensional transition metal carbides, nitrides, and carbonitrides, have garnered significant attention due to their remarkable potential for energy storage, electrocatalysis, and gas separation applications. The fabrication processes of MXene involve building up the MXene structure from constituent elements and the selective elimination of M-A bonds from the precursor MAX. However, considerable efforts are still required to design and develop efficient MXene-based technologies. This review article aims to briefly analyse the synthesis methods employed for MXene production, ranging from direct synthesis and conventional chemical wet etching approach to the more recent molten salt etching technique. The review highlights the advancements made in achieving precise control over the terminal groups, which is paramount for tailoring the properties of MXenes for specific applications. Furthermore, the potential of MXene-based materials for carbon capture applications, particularly in developing advanced adsorbents, is emphasized. The in-depth examination of MXene synthesis techniques and their implications for carbon capture applications provides a solid foundation for developing and optimizing these promising materials.

Trisodium Citrate as a Double-Edged Sword: Selective Etching Prussian Blue Analog Nanocubes into Orthogonal Frustums and Their Derivatives for Supercapacitors.

The construction of novel structured Prussian blue analogs (PBAs) by chemical etching has attracted the most attention to PBA derivatives with outstanding performance. In this work, the unprecedented PBA orthogonal frustums are first prepared from nanocubes through a selective chemical etching approach using trisodium citrate as an etchant. The citrate ions can chelate with nickel species from the edges/corners of NiCo-PBA nanocubes and then disintegrate NiCo-PBAs resulting in the generation of NiCo-PBA orthogonal frustums. The derived CoNi2S4/Co0.91S composites still inherit the original orthogonal frustum structure and possess outstanding supercapacitor performance. This study develops a popularized method to construct novel structured PBAs and brings inspiration for designing PBA-based electrodes with advanced electrochemical performance.

Optimization and test of a ring-ring typed atmospheric pressure plasma jet for optical fabrication

In recent years, the atmospheric pressure plasma jet (APPJ) has gained considerable attention in the field of optical fabrication because the chemical etching approach offers the advantage of avoiding mechanical damage to workpieces. This paper presents the development of an atmospheric pressure plasma machining system with a ring-ring typed APPJ, which exhibits several favorable characteristics. It has a relatively low processing temperature, no electrode corrosion, no plasma contamination, and a long discharge plume, etc. Optimization of the dimensional parameters and analysis of reactive gas flow rate are conducted through experimental investigations. Comparative experiments are carried out with the commonly used needle-ring typed APPJ, revealing significant improvements of the ring-ring typed APPJ, i.e., a fourfold increase in machining distance, a tenfold increase in machining efficiency, and a 58% enhancement in the stability of the material volumetric removal rate. Furthermore, on-line temperature monitoring of the footprint has been achieved due to the specific traits of the extended discharge plume. Fabrication experiments are conducted to demonstrate the significant correlation between the temperature and material removal rate, which shows the possibility of improving the accuracy of optical fabrication based on the ring-ring typed APPJ.

Large area single crystal gold of single nanometer thickness for nanophotonics

Two-dimensional single crystal metals, in which the behavior of highly confined optical modes is intertwined with quantum phenomena, are highly sought after for next-generation technologies. Here, we report large area (>104 μm2), single crystal two-dimensional gold flakes (2DGFs) with thicknesses down to a single nanometer level, employing an atomic-level precision chemical etching approach. The decrease of the thickness down to such scales leads to the quantization of the electronic states, endowing 2DGFs with quantum-confinement-augmented optical nonlinearity, particularly leading to more than two orders of magnitude enhancement in harmonic generation compared with their thick polycrystalline counterparts. The nanometer-scale thickness and single crystal quality makes 2DGFs a promising platform for realizing plasmonic nanostructures with nanoscale optical confinement. This is demonstrated by patterning 2DGFs into nanoribbon arrays, exhibiting strongly confined near infrared plasmonic resonances with high quality factors. The developed 2DGFs provide an emerging platform for nanophotonic research and open up opportunities for applications in ultrathin plasmonic, optoelectronic and quantum devices.

Surface modification of Polyether-ether-ketone for enhanced cell response: a chemical etching approach.

Polyether-ether-ketone (PEEK) is increasingly becoming popular in medicine because of its excellent mechanical strength, dimensional stability, and chemical resistance properties. However, PEEK being bioinert, has weak bone osseointegration properties, limiting its clinical applications. In this study, a porous PEEK structure was developed using a chemical etching method with 98wt% sulfuric acids and three post-treatments were performed to improve bone cell adhesion and proliferation. Four groups of PEEK samples were prepared for the study: Control (untreated; Group 1); Etched with sulfuric acid and washed with distilled water (Group 2); Etched with sulfuric acid and washed with acetone and distilled water (Group 3); and Etched with sulfuric acid and washed with 4wt% sodium hydroxide and distilled water (Group 4). Surface characterization of the different groups was evaluated for surface topology, porosity, roughness, and wettability using various techniques, including scanning electron microscopy, profilometer, and goniometer. Further chemical characterization was done using Energy-dispersive X-ray spectroscopy to analyze the elements on the surface of each group. Bone cell studies were conducted using cell toxicity and alkaline phosphatase activity (ALP) assays. The SEM analysis of the different groups revealed porous structures in the treatment groups, while the control group showed a flat topology. There was no statistically significant difference between the pore size within the treated groups. This was further confirmed by the roughness values measured with the profilometer. We found a statistically significant increase in the roughness from 7.22 × 10-3μm for the control group to the roughness range of 0.1µm for the treated groups (Groups 2-4). EDX analysis revealed the presence of a 0.1% weight concentration of sodium on the surface of Group 4, while sulfur weight percentage concentration was 1.1%, 0.1%, and 1.4% in groups 2, 3, and 4, respectively, indicating different surface chemistry on the surface due to different post-treatments. Cell toxicity decreased, and ALP activity increased in groups 3 and 4 over 7days compared with the control group. It is demonstrated that the surface modification of PEEK using a chemical etching method with post-processing with either acetone or sodium hydroxide provides a nano-porous structure with improved properties, leading to enhanced osteoblastic cell differentiation and osteogenic potential.

Silver-based SERS substrates fabricated using a 3D printed microfluidic device.

The detection of harmful chemicals in the environment and for food safety is a crucial requirement. While traditional techniques such as GC-MS and HPLC provide high sensitivity, they are expensive, time-consuming, and require skilled labor. Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical tool for detecting ultralow concentrations of chemical compounds and biomolecules. We present a reproducible method for producing Ag nanoparticles that can be used to create highly sensitive SERS substrates. A microfluidic device was employed to confine the precursor reagents within the droplets, resulting in Ag nanoparticles of uniform shape and size. The study investigates the effects of various synthesis conditions on the size distribution, dispersity, and localized surface plasmon resonance wavelength of the Ag nanoparticles. To create the SERS substrate, the as-synthesized Ag nanoparticles were assembled into a monolayer on a liquid/air interface and deposited onto a porous silicon array prepared through a metal-assisted chemical etching approach. By using the developed microfluidic device, enhancement factors of the Raman signal for rhodamine B (at 10-9 M) and melamine (at 10-7 M) of 8.59 × 106 and 8.21 × 103, respectively, were obtained. The detection limits for rhodamine B and melamine were estimated to be 1.94 × 10-10 M and 2.8 × 10-8 M with relative standard deviation values of 3.4% and 4.6%, respectively. The developed SERS substrate exhibits exceptional analytical performance and has the potential to be a valuable analytical tool for monitoring environmental contaminants.

Photo-electrochemical water splitting and electrochemical performance of silicon nanowire arrays

Silicon nanowires (SiNWs) were prepared using n-Si(100) by a simple two-step metal-assisted chemical etching (MACE) approach with different durations of 15 and 30 min. Surface morphology, structural, and optical properties of prepared SiNWs were investigated using Scanning Electron Microscope (SEM), x-ray diffraction (XRD) and UV–vis absorption, respectively. Under visible light, a photoelectrochemical cell (PEC) was used to measure the properties of a photoanode device that was fabricated based on n-SiNWs for splitting water. At 0.78 V, the SiNWs that were prepared in 30 min had a photocurrent density of 3.72 mA.cm−2 and a photoconversion efficiency (η) of 1.37%. Cyclic voltammetry (CV) measurements showed that both the n-Si(100) wafer and the n-SiNWs that were made with etching times of 15 and 30 min showed faradaic behavior with redox peaks. Electrochemical impedance spectroscopy (EIS) showed that the SiNWs photoanode prepared with 30 min of etching time had a charge transfer resistance of 3112.3. This is low enough to make it easy for charge to move across the interface. The Mott-Schottky (M-S) analysis revealed a high concentration of carriers of 4.77 × 1021 cm−3 at the working electrode/electrolyte interface,

High Gravimetric Capacitance MXene Supercapacitor Electrode Based on Etched Ti3C2Tx by Chemical Etching

Ti3C2T x MXene is one of the most promising electrode materials for supercapacitors, but it often suffers in poor experiment gravimetric capacitance, which limits practical applications in industry needs. Herein, etched Ti3C2T x MXene with high gravimetric capacitance is prepared by chemical etching of MXene with concentrated alkaline solution. The intercalation of K+ and the scissor role of OH− can simultaneously enlarge the interlayer spacing and cut the size of sheets, which lead to the high active‐site concentration and cation diffusion. As a result, the etched Ti3C2T x MXene displays high gravimetric capacitance of 368.1 F g−1 at 2 A g−1 and outstanding cycling stability without capacitance loss over 5000 cycles at 6 A g−1,and the surface capacitance contribution in etched Ti3C2T x MXene occurs to a greater extent compared with the pristine MXene. Moreover, the effect of chemical etching on the supercapacitor performance and energy‐storage mechanism indicates that the active‐size concentration and cation diffusion could be maximized when the chemical etching conditions are appropriate, leading to the highest performance of etched Ti3C2T x MXene. Herein, it is demonstrated that the chemical etching approach is applicable to design MXenes with high gravimetric capacitance to maximize their potential applications in energy‐storage applications and other fields.

Maximum spreading behavior of a water droplet on the aluminium surfaces with different wettabilities

This work demonstrates the maximum spreading behavior of water droplets on prepared surfaces: superhydrophilic (etched), hydrophilic (inherent nature), hydrophobic (treated with hexadecyltrimethoxysilane (HDTMS), and superhydrophobic (etched and HDTMS treated). Here, a simple chemical etching and immersion approach were used to modify the surfaces. Altering one surface property to the next shows a significant variation in the wetting behavior. The change in the wettability of the aluminium surface depends on its surface roughness and surface chemistry. The wettability of the fabricated surfaces was determined via water contact angle (WCA) measurement using a goniometer. A field emission scanning electron microscope (FESEM) and a 3-D optical non-contact profilometer were used to analyze the surface morphology and surface roughness of all manufactured surfaces, respectively. Additional features such as the droplet dynamics property of all surfaces were studied in detail. Finally, the experimental results for the maximum spreading factor were compared to the existing model.

Extending powder lifetime in additive manufacturing: Chemical etching of stainless steel spatter

• Chemical etching can eliminate most oxides from 316 L spatter. • A reduction in oxide coverage from 7–0.7% was possible. • Removal is thought to occur via initial dissolution of oxide-surrounding metal. • Etched spatter powder performed better in LPBF. • Reduced slag layer, and better wetting was seen for LPBF etched spatter. In laser powder bed fusion, unconsolidated metal powder on the build plate tends to comprise a proportion of oxidised powder after repeated use. This is generally caused by the generation of oxidised spatter particles during processing which can contaminate the powder bed, and be incorporated into future builds, ultimately undermining part integrity. Oxidised metal powder often results in porosity, poor layer-layer bonding and detrimental oxides in the printed part. This work uses a new chemical etching approach to remove oxides from the surface of oxidised stainless steel spatter powder. It was shown that a ten-fold reduction in oxide area coverage on spatter powder was possible through submersion in a solution of heated Ralph's etchant for one hour. Oxide removal is thought to occur mostly via dissolution of the metal surrounding and underneath oxide islands on the powder, allowing more aggressive oxide removal. LPBF processing was performed using spatter, etched and virgin powder sieved to an identical powder size range. Etched spatter showed a reduced oxide slag layer on track surfaces compared to spatter. In addition, incorporation of powder into tracks appeared improved after chemical etching of the powder. This work demonstrates that chemical etching has the potential to be used to increase the re-usability and lifetime of spatter or heavily used powder from widely used and corrosion resistant stainless steel powder.

Luminescent Silicon Nanowires as Novel Sensor for Environmental Air Quality Control.

Air quality monitoring is an increasingly debated topic nowadays. The increasing spillage of waste products released into the environment has contributed to the increase in air pollution. Consequently, the production of increasingly performing devices in air monitoring is increasingly in demand. In this scenario, the attention dedicated to workplace safety monitoring has led to the developing and improving of new sensors. Despite technological advancements, sensors based on nanostructured materials are difficult to introduce into the manufacturing flow due to the high costs of the processes and the approaches that are incompatible with the microelectronics industry. The synthesis of a low-cost ultra-thin silicon nanowires (Si NWs)-based sensor is here reported, which allows us the detection of various dangerous gases such as acetone, ethanol, and the ammonia test as a proof of concept in a nitrogen-based mixture. A modified metal-assisted chemical etching (MACE) approach enables to obtain ultra-thin Si NWs by a cost-effective, rapid and industrially compatible process that exhibit an intense light emission at room temperature. All these gases are common substances that we find not only in research or industrial laboratories, but also in our daily life and can pose a serious danger to health, even at small concentrations of a few ppm. The exploitation of the Si NWs optical and electrical properties for the detection of low concentrations of these gases through their photoluminescence and resistance changes will be shown in a nitrogen-based gas mixture. These sensing platforms give fast and reversible responses with both optical and electrical transductions. These high performances and the scalable synthesis of Si NWs could pave the way for market-competitive sensors for ambient air quality monitoring.

Bio-Inspired Hierarchical Micro-/Nanostructures for Anti-Icing Solely Fabricated by Metal-Assisted Chemical Etching.

We report a cost-effective and scalable methodology for producing a hierarchical micro-/nanostructured silicon surface solely by metal-assisted chemical etching. It involves two major processing steps of fabricating micropillars and nanowires separately. The process of producing micro-scale structures by masked metal-assisted chemical etching was optimized. Silicon nanowires were created on the micropillar’s surface via maskless metal-assisted chemical etching. The hierarchical micro-/nanostructured surface exhibits superhydrophobic properties with a high contact angle of ~156° and a low sliding angle of <2.5° for deionized water. Furthermore, due to the existence of microscale and nanoscale air trapped at the liquid/solid interface, it exhibits a long ice delay time of 2876 s at −5 °C, more than 5 times longer than that of smooth surfaces. Compared to conventional dry etching methods, the metal-assisted chemical etching approach excludes vacuum environments and high-temperature processes and can be applied for applications requiring hierarchical micro-/nanostructured surfaces or structures.

High-performance porous graphene oxide hollow fiber membranes with tailored pore sizes for water purification

Though graphene oxide (GO) membranes hold a good promise for water purification, their performance is restricted by permeation through long and tortuous diffusional pathways, leading to lower water permeance. In this study, we proposed a mild chemical etching approach to create nano-scale pores on the basal plane of GO nanosheets to make hollow fiber (HF) porous GO (PGO) membranes with improved water permeance and good dye rejection performance. Various characterization techniques were performed to monitor the pore generation and structural and compositional changes of synthesized PGO nanosheets. Results revealed that by controlling the etching time, PGO nanosheets with tunable pore size and surface chemistry as well as good solution processability were synthesized. The fabricated PGO HF membranes showed a well-stacked laminar morphology with uniform structures. The membrane made of PGO nanosheets etched for 5h (named PGO_5h) exhibited a 23-fold enhancement in pure water permeance from 0.129 LMHBar −1 for pristine GO membrane to 2.98 LMHBar −1 . Rejection tests with dyes in the molecular weights range between 200 and 900 g mol −1 were performed to prob the sieving capacity of the membranes on dye-containing wastewaters. The PGO_5h membrane showed molecular weight cut-off (MWCO) about 500 g mol −1 , demonstrating the great potential of PGO HF membranes for nanofiltration applications. • Porous graphene oxide (PGO) synthesis using mild chemical etching technique. • Controlling the pore sizes on the PGO by altering treatment times. • Processing the synthesized PGO into membranes on alumina hollow fibre support. • 23-folds enhancement in water permeation compared to pristine GO membranes. • Reject molecular of size larger than around 500 g mol −1 .

A robust superhydrophobic surface on AA3003 aluminum alloy with intermetallic phases in-situ pinning effect for corrosion protection

The tendency of AA3003 towards localized corrosion is one of the most challenging issues for its broader use. Intermetallic phases (IMPs) in AA3003 play dual contradictory roles: strengthening effect and initiating pitting. Solving this contradiction contributes to improvement of corrosion resistance and fully utilizing the potential of materials. Herein, a superhydrophobic surface with IMPs in-situ pinning effect was fabricated via a chemical etching approach combined with stearic acid (STA) modification. Thus, IMPs can provide sound support for the superhydrophobic surface and meanwhile eliminate the adverse effect of promoting localized corrosion. Formation mechanism of etching structure was attributed to the synchronous chemical reaction of IMPs and matrix phases in the etchant. Further modification with STA changed mico/nano hierarchical surface from hydrophilicity to superhydrophobicity. The as-prepared surface exhibited a maximum static contact angle of ~169° and a sliding angle of ~1°, possessing excellent superhydrophobicity. Besides, the wettability, self-cleaning, chemical stability, mechanical durability, and corrosion resistance properties of the superhydrophobic surface were comprehensively investigated. The results showed that the corrosion inhibition efficiency exceeded 99% in 3.5 wt% NaCl solution. The pinning direction of IMPs in superhydrophobic surface influenced its properties. It is anticipated that the construction of superhydrophobic surfaces will broaden its promising applications.

Simple Synthesis of Ru Decahedral Hollow Nanocages with Face-Centered Cubic Structure.

Metallic nanocrystals with specific morphologies are of great interest to various applications, in particular for nanocages with well-defined and controllable surface due to high surface-to-volume ratio with high utilization efficiency of atoms. In the present work, Ru decahedral nanocages were synthesized via a combination of seed-mediated growth and chemical etching approach over Pd decahedra seeds. To be specific, the Pd decahedra were synthesized via a standard procedure, on which the Ru out layers were grown by seed-mediated growth with a few nanometers. Subsequently, Ru decahedral nanocages were formed with selective chemical etching of Pd cores in acidic aqueous solution. The present work suggests an effective strategy towards synthesis of hollow nanocages.

Synthesis of aluminum alloy (AA) based composites TiO2/Al5083 and porphyrin/TiO2/Al5083: Novel photocatalysts for water remediation in visible region

Al5083 is an aluminium alloy with magnesium and traces of manganese and chromium. It is exceedingly resistant to attack by seawater and manufacturing chemicals. In this work, the synthesis of aluminium alloy (AA) based composites TiO2/Al5083 and Porphyrin/TiO2/Al5083 (Porphyrin = Tetrakis(4-carboxyphenyl) porphyrin (TCPP)) has been reported. We employed a chemical etching approach to activate the surface of AA. After the etching process, we successfully coated the TiO2 substrate on the Al5083 surface. In order to investigate the role of TiO2 thickness on photocatalytic efficiency, one, two and three layers of TiO2 were deposited on AA surface and three composites TCPP/TiO2(1)/Al5083, TCPP/TiO2(2)/Al5083 and TCPP/TiO2(3)/Al5083 were produced. We used these AA-composites as the new photocatalysts for degradation of the organic chloride Rhodamine B (RhB) under visible light irradiation. The role of porphyrin sensitizer in the photocatalytic degradation of RhB was investigated as well. The results showed that employing TCPP as a photosensitizer caused the redshift in TiO2/Al5083 absorption spectra reinforcing the photodegradation of RhB. Moreover, TCPP/TiO2(3)/Al5083 composite with three-layers of TiO2 has the highest performance with 29.19 percent of photodegradation efficiency in the visible region.

High-capacity CVD-grown Ge nanowire anodes for lithium-ion batteries: simple chemical etching approach for oxide removal

We demonstrated high-performance Ge nanowire (NWs) anodes for rechargeable lithium-ion batteries with high-capacity and high coulombic efficiency. The NWs were prepared using a simple chemical vapor deposition (CVD) method, which is favorable for the mass production of electrodes. The unstable oxides of Ge deteriorate the electrochemical characteristics of the batteries made from Ge-based anodes. To resolve the issue of the oxides and enhance the electrochemical performance, the oxides of the NWs were removed efficiently by a simple wet chemical etching method via a 10% HCl (aq) treatment. Transmission electron microscopy and energy-dispersive X-ray spectroscopy elemental mapping verified the removal of oxides. Charge and discharge capacity of the pristine NWs were 833.803 mAhg−1 and 650.63 mAhg−1 at first cycle. In comparison, the charge and discharge capacities after oxide removal were 1064.1 mAhg−1 and 905.6 mAhg−1 under the same conditions. The discharge capacity and coulombic efficiency of the oxide-removed NWs were 39.2% and 7.1% higher than those achieved without oxide removal. The coulombic efficiency of the oxide-removed NWs was higher than that of the pristine NWs (7.1% increase). The NWs were stable over 25 cycles at different C-rates. This approach provides an efficient and practical way to resolve the oxide issue of Ge-based anodes, and high-performance lithium-ion batteries were demonstrated using the oxide-removed NW anodes. This study presents an advance towards the realization of the commercial batteries based on Ge as an active electrode material.

Thermally induced evolution of the structure and optical properties of silicon nanowires

In the present paper, we report on the investigation of thermal annealing (TA) effect on structural and optical properties of crystalline silicon nanowires produced by metal-assisted chemical etching approach. In particular, the impact of TA on nanowire length, relative volume and size distribution of voids is described in terms of Lifshitz-Slyozov-Wagner theory considering the TA induced Oswald ripening in the SiNW arrays. It was also found that TA leads to a decrease of the SiNWs total reflection in the wide UV–VIS-IR spectral range. The reported effects can be used for tuning of crystalline SiNWs arrays in view of their further applications in photonics related fields.

Robust superhydrophobic surface with reinforced skeletons for corrosion protection

A superhydrophobic surface on AA3003 with a structure consisting of microrods and nanosheets was fabricated via a chemical etching approach combined with modification by stearic acid alcohol solution. Etching time, temperature and concentration were adjusted to optimize surface topographies and wettability. The optimized surface exhibited a static contact angle of ~167° and a sliding angle of ~1°. The surface structure consisting of microrods and nanosheets was responsible for the superhydrophobicity, the formation mechanism of which was discussed in detail. The morphology of the Al alloy surface after deep etching indicated that the intermetallic phases had a strong pinning effect, providing reinforced skeletons for the superhydrophobic surface. The upright nanosheets trapped air, inducing excellent superhydrophobicity. Mn oxide was formed on the surface after the etching treatment, which caused a brown coloration. This process provides an environment-friendly and low-cost strategy to fabricate durable and corrosion-resistant superhydrophobic surfaces on large-scale substrates, which could potentially be used in various indoor applications.