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Rational design of earth-abundant transition metal oxides catalysts is highly desirable for developing sustainable chemical processes. Herein, we demonstrate a prospective interstitial nitrogen engineering for fabricating oxygen vacancies (OVs)-rich nitrogen-doped-MnxCo3−xO4 (N-MnxCo3−xO4) oxide catalyst, in which the ratio of OVs concentration of N-MnxCo3−xO4 to Mn species is as high as 1:1, according to the characterizations of X-ray absorption (XAS) and X-ray photoelectron (XPS) spectroscopies. The promising strategy of interstitial nitrogen engineering through lattice distortion caused by the Jahn-Teller effect can significantly increase the amount of interstitial nitrogen. The resulting catalyst enables an additive-free aerobic dehydrogenation coupling of aromatic amine to afford azo compounds with > 99% yield and > 99% selectivity at 60 °C. We observed the superb catalytic activity is promoted by the enhanced oxygen mobility in OVs, which were created by the interstitial nitrogen in the catalyst matrix. The presence of interstitial nitrogen in transition metal oxides in this study shows how the manipulation of catalyst matrix can increase the OV sites to promote aerobic oxidation reaction.

Heteroatom-doped transition-metal oxides are potential non-noble-metal-based catalysts for the aerobic oxidation of alcohols because of the synergistic effects of their multiple active sites. However, the design of efficient heteroatom-doped transition-metal oxide catalysts is hindered by the complexity of the synergistic effects of multiple active sites. We have developed a practical strategy for fabricating nitrogen-doped MnO2 (N–MnO2), in which nitrogen is selectively doped at interstitial sites in MnO2. Use of N–MnO2 as a catalyst enabled additive-free aerobic oxidation of alcohols in > 99% yield at 30 ​°C. The catalytic activity of commercial MnO2 (< 1%) was negligible. Systematic studies of a series of Mn-based oxide catalysts, namely commercial MnO2, MnNxO2−x (prepared by traditional N doping by treatment with NH3), and N–MnO2 showed that N–MnO2 with abundant interstitial nitrogen dopant (1.8 ​mol%) had the best catalytic activity. Mechanistic studies suggested that the introduction of interstitial nitrogen as a dopant in MnO2 enhanced the adsorption and dissociation of oxygen on the N–MnO2 catalyst and promoted oxidative dehydrogenation of alcohols at interstitial nitrogen and oxygen vacancy sites. In situ infrared spectroscopy showed that C–N bonds (1161 ​cm−1) were formed and broken during benzyl alcohol oxidation. This confirms the importance of interstitial nitrogen in the catalytic cycle. This work provides an alternative strategy based on interstitial nitrogen doping for designing nitrogen-doped transition-metal oxides for aerobic oxidative reactions.

Surface properties and structures of materials are essential for their adsorption of pollutants in water. Humic acids (HA)-supported CeO2 nanosheet composites are synthesised by solvothermal method. The size of CeO2 nanosheets are approximately 100–500 nm. The obtained composite exhibits superior adsorption ability for Congo Red (CR) in water, which can be attributed to its unique structure and highly dispersed CeO2 nanosheet. The composite’s adsorption behaviour of CR follows a pseudo-second-order mode and Langmuir adsorption model well, and the maximum adsorptive capacity for CR achieves 260 mg g−1. The presence of CeO2 nanosheets enhances surface area and enriches the mesoporous structure of the composites, thereby promoting CR adsorption capacity.

Condensation of 2-amino-phenols with carboxylic acid derivatives has been practically used for the production of benzoxazoles, wherein the homogeneous catalytic system including strong acids and da...

Heteroatom doping in nanomaterials can import new active sites and promote catalytic activity. Here we report that Mn-doped Co3O4 nanorods (Mnx-Co3O4) via substituting Mn3+ (t2g3-eg1) for Co3+ (t2g...

A soft template, polyethylene glycol (PEG), was used for the preparation of polydimethylsiloxane (PDMS) oil absorbent. The preparation can be finished does not involve special equipment that normally required by conventional duplicating processes base on hard template. PEG/PDMS ratio, the key synthesis parameter, was systematically optimized in terms of both oil capacity and mechanical strength. Compared with previously reported PDMS materials developed using hard template, the optimized absorbents have comparable capacities of various oils in the range of 4.5–21.5 g/g, faster absorption rate and significantly improved mechanical strength with elongation at break significantly enhanced from 60 to 97% to greater than 200%. These improved properties can be explained by the regular distribution of macropore size that exhibits a signature twin-head peak dominated at about 120 and 200 μm. That fractional distribution is not affected by increased PEG/PDMS ratio until a structural collapse occurs at the ratio of 6 suggests specific and uniform interactions between PEG soft template and PDMS. Also examined are recyclability, anti-deformation property and oil-keeping performance, which are of practical importance under realistic storage and application conditions were also examined.

The synergistic effect in multi-active site catalysts is difficult to monitor, and the effect of their intrinsic mechanism on their catalytic performance is important but very difficult to understand owing to the large quantities of active species. Based on the results of density functional theory, herein we report the design and synthesis of an oxygen vacancy-abundant spinel-structured MnCo2O4 oxide as a highly efficient catalyst for alcohol oxidation, which highlights the importance of the synergistic effect between oxygen deficiencies and bimetal species.

Approaches for the catalytic oxidation of biomass-based 5-hydroxymethylfurfural (HMF) into valuable chemicals are in great demand; however, their development is still challenging. Herein, we present nitrogen-doped manganese oxide (N-MnO2) catalysts that possess extraordinary catalytic performance (a >99.9% 2,5-diformylfuran selectivity, a 100% HMF conversion, and decent reusability) at room temperature without any additives. Structural changes, i.e. slight elongation of the Mn–O bonds and reduction of the coordination number of Mn sites, occur after doping of nitrogen into MnO2, as confirmed via characterization by extended X-ray absorption fine structure (EXAFS), H2-temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). Mechanistic studies indicate that surface defect sites and coordinatively unsaturated Mn sites induced by nitrogen doping play a key role in promoting the oxidative activity.

We proposed a low-temperature rapid pyrolysis treatment (LTRP) to modify the caking property of a sub-bituminous coal. The coal was thermally treated in a rotating furnace in the temperature range 320–500 °C at a heating rate of ca. 80 °C/min. We also conducted an integrated investigation on some physicochemical properties, which were characterized by ultimate analysis, Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, pore volume, scanning electron microscopy, and thermogravimetry, of the treated coal to determine the modification mechanism. Caking and coking properties were evaluated by caking index (G) and crucible coking experiments, respectively. The results showed that LTRP significantly increased G, which reached the maximum at 410 °C, implying the existence of an optimum temperature. Crucible coking experiments showed that structure strength and micro-strength indices of the resulting cokes were also improved by LTRP treatment. A mechanism was proposed for the modification of the caking property. Suitable upgrading degree with suitable molecular masses and low melting donor hydrogen rich species presented within the coal, which dominated the development of caking property, was important. The synergistic effect of pore volume and the contents of total acidity groups, volatile matter, hydrogen, and oxygen in the coal determined the suitable upgrading degree.

Pd-based catalysts supported on CeO2-ZrO2 (CZ) mixed oxides have been universally applied toward the oxidation of methane, a strong greenhouse gas. Herein, CZ supports of different structures were prepared using hydrothermal (ST-CZ), co-precipitation (CP-CZ), and physical mixing (Mix-CZ) methods. Subsequently, the effects of the CZ support structure on the catalytic activity of the resulting Pd/CZ catalysts toward methane combustion were evaluated. ST-CZ shows the presence of cubic and tetragonal phases of CZ solid solutions, while CP-CZ is a pure tetragonal-phase solid solution and Mix-CZ is a mixture of CeO2 and ZrO2. The CZ solid solution improved the Pd dispersion and Pd2+/Pd ratio on the catalyst surface. Furthermore, CZ oxides with a two-phase composite structure resulted in higher oxygen storage capacity and oxygen mobility in the Pd/CZ catalysts than in the pure solid solution phase. Therefore, the Pd/ST-CZ catalyst shows superior catalytic activity for methane combustion than the other two catalysts.

Two-dimensional γ-Al2O3 nanosheet with rich pentacoordinate Al3+ sites which can nicely stabilize noble metals via strong interactions between metal and support has been focused. However, the synthesis of ultrathin and highly thermal-stable Al2O3 is challenging. Herein, we report an effective approach to synthesize ultrathin Al2O3 nanosheets with regular leaf-like architecture as well as high thermal-stability. A novel intercalation-swelling-exfoliation pathway was proposed to elucidate the formation of ultrathin sheet-like structure and then its morphology/thickness could be further adjusted via a dissolution-growth induced by phosphate. Meanwhile, the presence of phosphate further enhanced thermal stability of Al2O3 nanosheets due to the occupation or depletion of high-reactive sites and surface hydroxy groups. Subsequently, the thermally stable γ-Al2O3 nanosheets with moderate anchoring sites was used as a support of Pd and investigated for catalytic combustion of propane. The Pd/Al2O3 nanosheet exhibited a superior catalytic activity for propane combustion and the complete conversion was below 300 °C, more importantly, the outstanding resistance to high temperature (1000 °C) was observed, which was ascribed to the re-dispersion of Pd particles and the occurrence of strong metal-support interaction (SMSI) at high temperature.

Aromatic nitro compounds are versatile building blocks for organic synthesis because of easy transformation of the nitro group into other diverse functional groups. Herein, hierarchical mesoporous–macroporous CuAlPO-5 was prepared and found to exhibit excellent catalytic activity and stability for the oxidation of aromatic amines to nitroarenes. For the oxidation of bulky aromatic amine molecules (e.g., 1-naphthalenamine), hierarchical CuAlPO-5 exhibited higher selectivity to the product than homogeneous Cu catalysts and higher catalytic activity than traditional microporous CuAlPO-5; the former was attributed to shape selectivity to the product and the latter was attributed to improved diffusion of bulky molecules inside the meso- and macropores. After CuAlPO-5 was used five times in the oxidation of 4-bromoaniline, >98.6 % conversion and 98.1 % selectivity to the product were obtained. This shows the potential and attractiveness of this method for the preparation of nitroarenes by the selective oxidation of organic amines.

Heterogeneous catalytic reactions of aromatic organic molecules over zeolite catalysts present many challenges because of the shape selectivity of the micropores of conventional zeolites that limits the diffusion of aromatic molecules. Herein, Ullmann coupling reactions of phenols with nitro-substituted aryl halides were catalyzed by rare-earth-doped mesoporous AlPO-5 zeolites in the absence of ligands. The AlPO-5-MAlPO-5-M zeolites had a pure AFI structure and consisted of spherical particles assembled by nanofibers. The rare-earth elements were highly dispersed in the AlPO-5-MAlPO-5-M samples. The LaAlPO-5-MAlPO-5-M zeolite is an excellent catalyst for Ullmann coupling reactions of phenols and nitro-substituted aryl halides. Mesoporous LaAlPO-5 has an excellent stability and recyclability in the Ullmann coupling of p-X-nitrobenzene (X=Cl, Br, and I) with 2-naphthol. These results are important in the exploration of attractive Ullmann coupling reactions and in the development of mesoporous zeolite catalysts for other organic reactions.

Sb-containing catalysts (SbZrOx (SbZr), SbCeOx (SbCe), SbCeZrOx (SbCeZr)) were prepared by citric acid method and investigated for the selective catalytic reduction (SCR) of NOx with NH3 (NH3-SCR). SbCeZr outperformed SbZr and SbCe and exhibited the highest activity with 80% NO conversion in the temperature window of 202&ndash, 422 &deg, C. Meanwhile, it also had good thermal stability and resistance against H2O and SO2. Various characterization methods, such as XRD, XPS, H2-TPR, NH3-TPD, and in situ diffuse reflectance infrared Fourier transform (DRIFT), were applied to understand their different behavior in NOx removal. The presence of Sb in the metal oxides led to the difference in acid distribution and redox property, which closely related with the NH3 adsorption and NO oxidation. Br&oslash, nsted acid and Lewis acid were evenly distributed on SbCe, while Br&oslash, nsted acid dominated on SbCeZr. Compared with Br&oslash, nsted acid, Lewis acid was slightly active in NH3-SCR. The competition between NH3 adsorption and NO oxidation was dependent on SbOx and metal oxides, which were found on SbCe while not on SbCeZr.

K+ was loaded onto the acid-treated Loy Yang (LY) lignite. The effects of K+ on combustion behavior of LY lignite were investigated using thermogravimetric analysis. The Fourier transform infrared spectroscopy and X-ray diffraction results showed that K+ was successfully loaded on the lignite, and it was in the form of amorphous state. Ignition temperature (Ti) values for the K+―loaded samples were higher than that for the acid-treated sample, and Ti increased with increasing K+ content. The opposite relationship was observed for peak temperature (Tp). Based on the changes in Ti, Tp, maximum combustion rate, and activation energy calculated using the Kissinger–Akahira–Sunose and Ozawa–Flynn–Wall methods, a mechanism was proposed for the catalytic combustion. K+ could enhance the release of volatiles. Moreover, K+ acted as a carrier of oxygen and promoted the oxygen transfer to char, resulting in the increase in CO2 yield.

In this study, we reported the first example of multi-functional 1-triacontanol-polymerized-octadecylsiloxane (1-triacontanol-PODS) coatings. The multi-functional 1-triacontanol-PODS coatings are formed on various substrates including cotton wool, filter paper, sponge, and glass via immersing the substrates in hot solutions (∼50 °C) of 1-triacontanol, octadecyltrichlorosilane (OTS) and ethanol. After coating, it is found that the 1-triacontanol-PODS-coated materials possess with superhydrophobicity, superoleophilicity and anti-corrosion ability. Furthermore, highly efficient oil/water separation and excellent self-cleaning ability were also observed on the 1-triacontanol-PODS-coated materials. For instance, the flux of 1-triacontanol-PODS coating modified cotton wool for ClCH 2 CH 2 Cl/H 2 O separation was ranged from 5677 to 32,157 L m −2 h −1 after 50 cycles, and the mass-based absorption capacities for the oils are in the range 15–31; Both micro (>20 μm) and nano dust particles (∼50 nm) were fully removed from 1-triacontanol-PODS coating-modified glass substrate.

Superhydrophobic and superoleophilic sponges were fabricated by immersion in an ethanol solution of octadecyltrichlorosilane. The resulting coating strongly adheres to the sponges after curing at 45 °C for 24 h. Absorption capacities of 42-68 times the polymerized octadecylsiloxane sponge weight were obtained for toluene, light petroleum, and methylsilicone oil. These adsorption capacities were maintained after 50 cycles.

Developing a low-cost route to synthesize mesoporous TS-1 (MTS-1) is of great importance because of its practical application in industry. Herein, we first synthesized a copolymer containing quaternary ammonium groups by a mesoporous template comprising inexpensive starting materials. Subsequently, waterglass (sodium metasilicate), TiCl3, and copolymer were dispersed in the preformed seeds emulsion, resulting in a gel for synthesizing MTS-1. The counterpart material (CTS-1) was also synthesized by the same procedure except for the absence of the copolymer. Compared with CTS-1, the MTS-1 exhibits good crystallinity and well-defined tetrahedral coordinated Ti species (TiIV) in the framework as well as excellent catalytic activity in the oxidation of bulky molecules, such as dibenzothiophene and benzyl phenyl sulfide. This feature may be attributed to the fact that the quaternary ammonium groups on copolymer facilitates the formation of the MFI structure and energetically incorporates the Ti species into the...

Correction for ‘Boosting the activity of catalytic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran over nitrogen-doped manganese oxide catalysts’ by Qingping Ke et al., Green Chem., 2019, DOI: 10.1039/c9gc01041f.

The mesoporous zeolite TS-1 shows high activity and high reusability in the oxidation of sulfides to sulfoxides.

Heterogeneous catalytic reactions of aromatic organic molecules over zeolite catalysts present many challenges because of the shape selectivity of the micropores of conventional zeolites that limits the diffusion of aromatic molecules. Herein, Ullmann coupling reactions of phenols with nitro-substituted aryl halides were catalyzed by rare-earth-doped mesoporous AlPO-5 zeolites in the absence of ligands. The AlPO-5-MAlPO-5-M zeolites had a pure AFI structure and consisted of spherical particles assembled by nanofibers. The rare-earth elements were highly dispersed in the AlPO-5-MAlPO-5-M samples. The LaAlPO-5-MAlPO-5-M zeolite is an excellent catalyst for Ullmann coupling reactions of phenols and nitro-substituted aryl halides. Mesoporous LaAlPO-5 has an excellent stability and recyclability in the Ullmann coupling of p-X-nitrobenzene (X=Cl, Br, and I) with 2-naphthol. These results are important in the exploration of attractive Ullmann coupling reactions and in the development of mesoporous zeolite catalysts for other organic reactions.

SO2 capacity of the obtained TMG-AlPO-5/cordierite honeycomb ceramic (CHC) adsorbent was measured to be 1.13 mol per mol TMG. More importantly, compared with literature reported supported ionic liquids, it is featured by a significantly improved adsorption rate (t0.9 reduced from >30 min to ∼0.1 min) and negligible pressure drop.

Edges often play a role as active centers for catalytic reactions in some nanomaterials. Therefore it is highly desirable to enhance catalytic activity of a material through modulating the microstructure of the edges. However, the study associated with edge engineering is less investigated and still at its preliminary stage. Here we report that Cu2MoS4 nanosheets with indented edges can be fabricated through a simple chemical etching route at room temperature, using Cu2MoS4 nanosheets with flat ones as sacrifice templates. Taking the electrocatalytic hydrogen evolution reaction (HER), photocatalytic degradation of rhodamine B (RhB) and conversion of benzyl alcohol as examples, the catalytic activity of Cu2MoS4 indented nanosheets (INSs) obtained through edge engineering was comparatively studied with those of Cu2MoS4 flat nanosheets (FNSs) without any modification. The photocatalytic tests revealed that the catalytic active sites of Cu2MoS4 nanosheets were associated with their edges rather than basal planes. Cu2MoS4 INSs were endowed with larger electrochemically active surface area (ECSA), more active edges and better hydrophilicity through the edge engineering. As a result, the as-fabricated Cu2MoS4 INSs exhibited an excellent HER activity with a small Tafel slope of 77 mV dec(-1), which is among the best records for Cu2MoS4 catalysts. The present work demonstrated the validity of adjusting catalytic activity of the material through edge engineering and provided a new strategy for designing and developing highly efficient catalysts.

Two ultra-stable Y zeolites (USY550 and USY600) with mesoporous volumes of 0.15 and 0.25 cm 3 /g were prepared by steam dealumination at 550 and 600 °C, respectively. Pd catalysts were supported on γ-Al 2 O 3 , H-forms of zeolite Y (HY), mesoporous USY for hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DM-DBT). The 4,6-DM-DBT conversions over Pd/USY550 (85.7%) and Pd/USY600 (76.9%) are higher than over Pd/HY (43.7%) due to the facilitated mass transfer of 4,6-DM-DBT in the mesopores USY. The better HDS performance of Pd/USY than Pd/γ-Al 2 O 3 is attributed to the stronger acidity of USY, as demonstrated by the stepwise temperature-programmed desorption of ammonia. Thermogravimetric and X-ray photoelectron spectroscopic analysis of the used catalysts showed that the poison of Pd particles over the supports by sulfur was responsible for the catalyst deactivation.

Design and preparation of highly active hydrodesulfurization (HDS) catalysts is very important for the removal of air pollution. Herein, we report an extraordinarily active HDS catalyst, which is synthesized by loading of Pd on mesoporous zeolite Y (Pd/HY-M). The mesoporous zeolite Y is successfully synthesized using a water glass containing N,N-dimethyl-N-octadecyl-N-(3-triethoxysilylpropyl) ammonium [(C(2)H(5)O)(3)SiC(3)H(6)N(CH(3))(2)C(18)H(37)](+) cation as a mesoscale template. Compared with mesoporous Beta and ZSM-5 supported Pd catalysts (80.0% and 73.4% for Pd/HBeta-M and Pd/HZSM-5-M, respectively) as well as commercial catalyst of γ-Al(2)O(3) supported Pd catalyst (31.4%), Pd/HY-M catalyst exhibited very high activity in HDS of 4,6-dimethyldibenzothiophene (4,6-DM-DBT, 97.3%). The higher activity of Pd/HY-M than that of Pd/HBeta-M and Pd/HZSM-5-M is assigned to the larger micropore size of zeolite Y compared to that of Beta and ZSM-5. Theoretical simulation and adsorption experimental data show that 4,6-DM-DBT has difficulty entering the micropores of ZSM-5 and Beta zeolites, but the micropores of Y zeolite are accessible.

Formation of layered nanosheets and micro-spheres from a simple self-assembly and polycondensation of n-octadecylsilane (PODS) in water and toluene is demonstrated, respectively. The structure of the micro-spheres was characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). According to the TEM images, it was firstly confirmed that the micro-spheres consist of stacks of bilayered polymerized n-octadecylsilane with head-to-head arrangements. The co-effects of water and solvent were proposed to control the octadecyltrichlsilane hydrolysis process and eventually the morphology of the micro-spheres. A micelle formation mechanism for the formation of the PODS micro-spheres under the co-effects of water and solvent were firstly proposed.

Surfaces with superhydrophobicity are important in a number of biological and industrial processes. Hierarchical film based on polydimethylsiloxane (PDMS) and SiO 2 with a water contact angle of 155° and sliding angle of 6° was prepared by a facile drop-coating method. Surface modification of SiO 2 spheres was found to improve particle dispersion and increase their compatibility with PDMS, which eventually affected the stability of the hierarchical structure. Different curing temperatures were studied for enhancing the hydrophobicity of the hierarchical structure. We examined the mechanical robustness of the superhydrophobic surface by using a shear test, and found that the hierarchical PDMS-based SiO 2 films retained superhydrophobicity after 48 KPa mechanical shears.

A superhydrophobic polymerized n-octadecylsilane (PODS) surface with a highly ordered lamellar structure was obtained via a one-step solution immersion process. The PODS surface had water contact and sliding angles of 159° and ∼0°, respectively. A hydrophilic/superhydrophobic surface was then obtained by chemically bonding nano-SiO 2 onto the PODS surface. This SiO 2 /PODS layer exhibited dew-enhancing ability, similar to that of the surface of the stenocara beetle. Vapor condensation occurring heterogeneously on the SiO 2 /PODS surface is proposed to explain the dew-enhancing property, and these hydrophilic/superhydrophobic surfaces may have applications in enhanced heat transfer.

Polymerized n -octadecylsiloxane (PODS) was prepared by coating glass substrates with liquid ocatdecyltrichlorosilane (OTS) followed by dipping-in a solvent. The morphology control of PODS was investigated by the post curing temperature as well as the use of different solvents. The resulting substrates were characterized by scanning electron microscopy (SEM), contact angle measurements, and wide angle X-ray diffractometry (XRD). It is shown that both post curing temperature and extracting solvents affect the morphology of PODS. The temperature dependent morphology was investigated and is ascribed to the physiochemical properties of PODS. For the solvent-dependent morphology, it is proposed that the solvation capability of a solvent to OTS and the presence of a hydrophilic/hydrophobic interface are critical in the PODS morphology. This paper shows the controlling parameter and possible explanation in the crystallinity and wettability of PODS films, which may be useful to other silane-based systems.

A new strategy for the synthesis of epoxides is presented. This process allows the direct synthesis of epoxides from alkenes and aldehydes through C–H functionalization and C–C/C–O bond formation.

Developing functional porous materials with highly efficient oil–water separation ability are of great importance due to the global scale of severe water pollution arising from oil spillage and chemical leakage. A solution immersion process was used to fabricate polydimethylsiloxane (PDMS)-coated cotton, which exhibited superhydrophobic and superoleophilic properties. The water contact angle of ∼157° and mass of ∼1.49 g were retained after 1000 compression cycles, indicating that the PDMS was strongly attached to the cotton fibres. The PDMS-coated cotton absorbed various oils and organic solvents with high selectivity, high absorption capacity (up to 7080 wt.%), and good recyclability (exceeding 500 cycles). Notably, the loading capacity of the PDMS-coated cotton against water exhibited a similar trend to its oil absorption capacity. These findings will further the application of superhydrophobic and superoleophilic porous materials in oil/water separation.

A new strategy for the synthesis of epoxides is presented. This process allows the direct synthesis of epoxides from alkenes and aldehydes through C–H functionalization and C–C/C–O bond formation.

The mesoporous zeolite TS-1 shows high activity and high reusability in the oxidation of sulfides to sulfoxides.

We fabricated the first superhydrophobic (SH) surface with microcavities, using a simple process. The process included an improved template method (ITM) for constructing the SH surface with cavities, using taro leaves as a pattern mask, and a dip-coating method for modifying the SH surface. The results obtained using the ITM are significantly better than those achieved using traditional template methods. In addition, the water-repellence of the microcavities surface was significantly enhanced by decorating with a layer of polymerized n-octadecylsiloxane nanosheets.

The present paper describes the simple and low-cost process for the production of a superhydrophobic surface with micronano hierarchical structure from the chemisorptions of SiO(2) nanoparticles onto polymerized n-octadecylsilane. The process was carried out under ambient conditions without the use of expensive equipment. The as-prepared micronano-binary films exhibited a very high contact angle of 179.9 degrees and a low contact hysteresis of 2.5 degrees . On the basis of the results of the characterization techniques, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and contact angle (CA) measurements, a formation mechnism of the superhydrophobic micronano structure was proposed. Drop impact experiments on the modified-glass substrate showed that the as-prepared films possess a high-impalement threshold.

Superhydrophobic nanosheet assemblies of polymerized n-octadecylsiloxane (PODS) were obtained on glass using n-octadecyltricholorsilane (OTS) as a starting material and acetone as the extracting agent. The coating layers were characterized by infrared spectroscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, and contact angle measurements. It was shown that the PODS nanosheets consist of stacks of bilayered polysilsequioxane of OTS in a head-to-head arrangement. The relative humidity of the environment was found to control the self-assembly and eventually the morphology of the final coating. A coating-formation mechanism was proposed to describe the formation of OTS nanosheets on the basis of quick OTS hydrolysis, fast self-assembly, and slow polycondensation (i.e., after OTS hydrolysis, nanosheets can be formed only when the self-assembly process proceeds at a faster rate than polycondensation, which implies critical controlling factors in the formation of well-ordered OTS self-assembled monolayers (SAMs)).