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A series of Cu-doped ZnO (Cu-ZnO) photocatalysts have been synthesized by a simple hydrothermal method. X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) confirmed that Cu ions have been effectively incorporated into the ZnO lattice, and as the doped Cu amounts increased to 1.5%, the Cu2O will be formed. Under the effect of Cu ions and the Cu2O/ZnO heterojunction, the prepared 1.5% Cu-ZnO nanocomposites exhibited superior catalytic activity in photodegradation of Rhodamine B (RhB) dye under UV light irradiation. RhB could be degraded 99.9% after the irradiation time of 21 min. The photodegradation rate constant achieved 0.2429 min−1, which was 2 times than that of pure ZnO. The results of photoluminescence (PL) and photoacoustics (PA) spectroscopy studies indicated that the recombination efficiency of photogenerated electrons and holes was decreased for 1.5% Cu-ZnO nanocomposites as compared to that of samples. The surface photovoltage (SPV) and the transient photovoltage (TPV) measurements directly demonstrated that separation efficiency was improved, and the recombination time of electrons and holes in 1.5% Cu-ZnO nanocomposites was prolonged due to the synergistic effect of the impurity level and p-n heterojunction. Finally, the possible mechanism is proposed to illuminate the photogenerated charge behavior under UV light irradiation，and the roles of doped Cu and precipitated Cu2O in the photodegradation process were discussed. This work opens a novel avenue to preparing the metal doping photocatalysts with efficiently charge separation and charge transfer.

The construction of oxygen vacancies, as one of defects engineering, is a promising strategy to boost the electrocatalytic activity. Herein, CuO nanoflakes enriched with oxygen vacancies were successfully synthesised via a simple one-pot method with stirring. High-angle annular dark-field scanning, X-ray photoelectron spectroscopy and electron spin resonance spectroscopy were performed to confirm the existence of enriched oxygen vacancies. The as-synthesised CuO nanoflakes enriched with oxygen vacancies and exhibited an excellent performance for glucose detection with a lower onset-potential of +0.22 V, ultrahigh sensitivity of 4870 μA mM−1 cm−2 and low detection limit of 0.5 μM. The superior performance of the CuO nanoflakes may be attributed to surface oxygen vacancies, which accelerate the adsorbed hydroxyl ions to promote the formation of Cu3+ species, thereby, reducing the one-potential and facilitating the glucose oxidation. This work would serve the guide for the rational design of other efficient catalysts for glucose detection via constructing oxygen vacancies.

X-ray photoelectron spectroscopy (XPS) is an efficient technique for recognizing the state of elements. However, the effects of X-ray irradiation on change in the chemical state are sometimes ignored, which may impair the understanding of the environmental behavior of these elements. This study determined the change in the U 4f spectra induced by X-ray irradiation during XPS detection. For U(VI) on non-semiconductors, X-ray irradiation led to a negative shift of U 4f7/2 to ∼ 380.8 eV due to the break of the uranyl molecules, but not resulting in U(IV) species. However, owing to the photocatalytic reduction of U(VI), the irradiation of U(VI) loaded semiconductors rapidly induced the negative shift of U 4f7/2 peak to ∼ 379.8 eV, which is the characteristic of U(IV). Moreover, apparent photo-reduction occurred even if the samples were far from the center of the X-ray beam (>3971 μm). Based on these findings, methods for reducing potential error due to X-ray irradiation are suggested, including using the minimum scan time, measuring uranium-containing samples first or independent of other samples, and using X-ray of lower intensity. The results indicated that X-ray induced alteration to the chemical states must be considered when using X-ray techniques.

The carrier concentration of the indium tin oxide (ITO) thin films can be enhanced by supplying extra conducting electrons with tin dopants. However, defects and impurities, which are rich around grain boundaries, result in strong carrier scattering. In this work, ITO films prepared by magnetron sputtering were subjected to supercritical carbon dioxide (SCCO2) fluid treatment with different concentrations of InCl3 solutions, In3+ ions were introduced in the grain boundaries for the purpose of regulating defects and impurities there. The photoelectric performance of ITO films was improved significantly after the SCCO2 fluid treatments, which was interpreted for the effects of SCCO2 on as-deposited ITO microstructures based on the experimental results of X-ray photoelectron spectroscopy and positron annihilation lifetime spectroscopy. Upon the SCCO2 fluid treatment, the dehydration effect passivated the dangling bonds around the grain boundaries, meanwhile, the indium ions diffused into the grain boundaries, resulting in the formation of ITO-like lattice structure there.

With the ever-increasing oil spillages, oil-water separation has attracted widespread concern in recent years. In this work, a nature-inspired polyphenol method has been developed to fabricate the durable superhydrophobic surfaces for the oil-water separation. Inspiring from the adhesion of polyphenol and reducing capacity of free catechol/pyrogallol groups in polyphenol, firstly, the simple immersion of commercial materials (melamine sponge, PET, and nonwoven cotton fabrics) in tannic acid (TA) solution allows to form a multifunctional coating on the surface of sponge or fabrics, which was used as reducing reagent to generate Ag nanoparticles (NPs). Then, decoration of 1H, 1H, 2H, 2H-perfluorodecanethiol (PFDT) molecules produced superhydrophobic surfaces. The surface topological structure, chemical composition, and superhydrophobic property of the as-prepared surface are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), and water contact angle (WCA) measurements. The WCAs of as-prepared sponge and fabrics were higher than 150°. The stability, absorption capacity, and recyclability of as-prepared sponge and fabrics were investigated. The as-prepared sponge demonstrates high oil/water selectivity and high absorption capacity (66–150 g/g) for a broad variety of oils and organic solvents, and was chemically resistant, robust against abrasion, and long-term durability in harsh environments. Most important of all, it can continuously separate various kinds of oils or organic pollutants from the surface of water. This study presents a facile strategy to fabricate superhydrophobic materials for continuous oil-water separation, displaying great potential in large-scale practical application.

In this paper, mesoporous Cu2O–CeO2 nanospheres were fabricated via a facile, low-temperature solution route in the presence of poly(2-vinylpyridine)-b-poly(ethylene Oxide) (P2VP-b-PEO) block copolymers. The prepared mesoporous Cu2O–CeO2 nanospheres were characterized systematically by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption/desorption. The formation mechanism of mesoporous Cu2O–CeO2 nanospheres was discussed. The results show that the molar ratios of Ce3+/Cu2+ and the reaction time have an important influence on the nanostructure of Cu2O–CeO2 composite spheres. The resultant Cu2O–CeO2 nanospheres exhibit superior catalytic activities in the reduction of 4-nitrophenol to 4-aminophenol by NaBH4. The activity factor (K = k/m) for the Cu2O–CeO2 nanospheres prepared with the molar ratio of Ce3+/Cu2+ of 5/1 is 3006.6 s−1 g−1, which is much higher than reported values. This paper demonstrates a highly controllable approach to the production of mesoporous Cu2O–CeO2 nanospheres, which have potential applications in the areas of catalysis, adsorption, sensors and so on.

A series of epoxy resin (EP) composite coatings reinforced with functionalized cubic boron nitride (FC-BN) and functionalized hexagonal boron nitride (FH-BN) were fabricated successfully on 316L stainless steel by hand lay-up technique. The structure properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The morphologies were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, UMT-3 tribometer and surface profiler were used to investigate tribological behaviors of as-prepared composite coatings under dry friction and seawater conditions respectively. The results demonstrated that the presence of FC-BN or FH-BN fillers could greatly decrease the friction coefficient (COF) and wear rate of epoxy, in addition, composite coatings possess better tribological properties under seawater condition which was attributed to the lubricating effect of seawater. Moreover, FC-BN endows the composite coatings the highest wear resistance, and FH-BN /EP composite coatings exhibited the best friction reduction performance which is attributed to the self-lubricating performance of lamella structure for FH-BN sheet.

Graphene oxide is modified by diethylenetriamine through a one-step route to prepare GO-NH(CH 2 ) 2 NH(CH 2 ) 2 NH 2 (GO-DETA), which has primary and secondary amino groups and carboxyl groups. GO-DETA is characterized by Fourier transform-infrared spectrum (FT-IR), X-ray diffraction spectroscopy (XRD), thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The catalytic performance of obtained GO-DETA is investigated in Knoevenagel condensation and Michael addition in water; the results show it can be used as an efficient and stable catalyst. In addition, it has other features, such as simple preparation, good recyclability and environmental friendliness.

Herein, we reported a Z-scheme 0D/2D Ag6Si2O7/CN composite photocatalyst via simple precipitation method, where the electron structure and optical properties of Ag6Si2O7 and CN materials were studied by theoretical computation. The XPS, TEM, radical trapping experiments and ESR measurement results illustrated the formation of the Z-scheme 0D/2D Ag6Si2O7/CN heterostructure. The crystal structure and surface composition of the prepared materials were characterized by XRD, SEM and FT-IR. The UV–vis DRS, PL, I-t, and EIS demonstrated that all composites have improved light absorption ability and enhanced photo-generated charge separation rate. The construction of 0D/2D Ag6Si2O7/CN Z-scheme heterojunction is helpful to improve photodegradation ability, which can not only enhance the separation and transmission efficiency of the photogenerated carriers, but also retain the strong redox ability of photocatalysts. This paper provides a novel comprehension of the mechanism of Z-scheme composites by combining theoretical calculations and experiments.

Facile construction of multifunctional fabrics with durability still remains a challenge in the past decade. In this work, we report a facile fabrication of non-fluorinated superhydrophobic and antibacterial cotton fabric surfaces via in situ growing zeolitic imidazolate framework-8 (ZIF-8) nanocrystals on cotton fibers under room temperature condition and subsequently coating with polydimethylsiloxane (PDMS). The surface morphology and chemical composition of treated fabric have been characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS). The as-prepared cotton fabric showed superhydrophobic property with a water contact angle (WCA) of 151.36° and a sliding angle of 3.6° and excellent antibacterial properties against E. coli and S. aureus. The durability of the superhydrophobic and antibacterial fabrics was evaluated by repeated washing and abrasion cycles. The as-prepared fabrics retained their excellent antibacterial property and superhydrophobicity after 300 cycles of abrasion and 5 cycles of washing. The robustness of superhydrophobicity and antibacterial activity made this method has wild application prospects in biomedical field in the future.

The nanocomposite nc-ZrCN/a-CNx films with a carbon content varying from 34 to 61 at.% were deposited by filtered cathodic vacuum arc technique (FCVA) under different C2H2/N2 reactive gas flows. The effect of different carbon contents on compositional, nanostructural characteristics of nanocomposite nc-ZrCN/a-CNx films was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM), Raman scattering spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS). Results showed that nanocomposite nc-ZrCN/a-CNx films were composed of about 8 nm sized ZrCN nanocrystalline embedded in different amount of a-CNx amorphous matrix. Mechanical properties of nanocomposite nc-ZrCN/a-CNx films showed a significant dependency on thickness of a-CNx matrix. Nanocomposite nc-ZrCN/a-CNx film reached the highest hardness (41 GPa) and reduced modulus (320 GPa) when the thickness of a-CNx matrix was around 0.4 nm. Nanocomposite nc-ZrCN/a-CNx film at higher carbon content has lower friction coefficient (0.2) and better wear resistance. The nanocomposite films possess lower Icorr and higher Rp values than the single phase film.

P25 or self-prepared TiO 2 coated polypyrrole (PPy/P25 or PPy/TiO 2 ) composites as novel adsorbents were prepared. Their adsorption–desorption characteristics for Methylene Blue (MB) were comparatively investigated. X-ray photoelectron spectroscopy (XPS) showed that PPy/TiO 2 possessed higher doping level than PPy/P25. Thermogravimetric analysis (TGA) indicated that PPy/TiO 2 contained more PPy than PPy/P25. The results of water vapor adsorption suggested that the PPy/TiO 2 composite was more hydrophobic than PPy/P25. The adsorption results revealed that the composites pretreated in the solution with higher pH value exhibited larger adsorption capacities. The ionic concentration in MB solution slightly impacted the removal of MB by the PPy/TiO 2 composite. The adsorption equilibrium results showed that the adsorption of MB was completed in a short time of 30 min. Pseudo-second-order and Langmuir isotherm models were effectively employed to describe the adsorption behavior of MB. PPy/TiO 2 and PPy/P25 were found to have better removal ability for MB compared with pure PPy; especially PPy/TiO 2 , on which the maximum adsorption amount was about 3.6 or 5.5 times higher than that of PPy/P25 or pure PPy, respectively. The thermodynamic analysis indicated that the adsorption of MB was spontaneous and endothermic in nature. The regeneration experiments exhibited that PPy/TiO 2 can be reused at least seven times without obvious loss of its original adsorption capacity. Electrostatic interaction, hydrogen bonding and hydrophobic interaction played the roles in MB adsorption performance. It is expected that the PPy/TiO 2 composite can be considered as a stable adsorbent for dye removal.

Bi-doped hollow titania spheres were prepared using carbon spheres as template and Bi-doped titania nanoparticles as building blocks. The Bi-doped titania nanoparticles were synthesized at low temperature. The prepared hollow spheres were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV–vis diffuse reflectance spectrum (DRS) and X-ray photoelectron spectroscopy (XPS). The effects of Bi content on the physical structure and photocatalytic activity of doped hollow titania sphere samples were investigated. Results showed that there was an optimal Bi-doped content (4%) for the photocatalytic degradation of methylene blue (MB).

A novel photocatalyst (Ce, C-codoped titania) was synthesized through a modified sol–gel method under mild condition. The as-prepared sample was investigated by XRD, SEM, DRS and XPS. It was found that the as-prepared photocatalyst was composed of spheroidal particles, which were smaller than undoped ones. The absorbance spectrum of Ce, C-codoped TiO2 exhibited significant red-shift to visible region. It can be ascribed to appearance of a new electronic state in the middle of the TiO2 band-gap. Furthermore, cerium doping could slow the radiative recombination process of photogenerated electrons and holes in TiO2. Accordingly, for degradation of dye Reactive Brillint Red X-3B (C.I. reactive red 2) under visible light, the photocatalytic activity of Ce, C-codoped TiO2 improved much compared to other samples (C-doped TiO2, undoped TiO2 and P25).

Bi2O3–TiO2 composite films were synthesized by a sol–gel method under mild condition (i.e. low temperature and ambient pressure). The as-prepared films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, infrared spectra and fluorescence spectra. The results showed that Bi2O3–TiO2 composite films were composed of anatase titania and Bi2O3. TiO2 particles were deposited on the surface of Bi2O3 to form uniform film. Incorporating Bi2O3 with TiO2 leads to increased surface OH group density. All Bi2O3–TiO2 composite films exhibited higher photocatalytic activity compared with pure TiO2 under solar irradiation, while the film with Bi/Ti atomic ratio of 1.25% showed the highest photocatalytic activity. Furthermore, the as-prepared films can be reused with little photocatalytic activity decreasing. Without any further treatment besides rinsing, the photocatalytic activity of Bi2O3–TiO2 (1.25%) films was still higher than 77% after six-cycle utilization.

A novel and simple method for preparing F-doped anatase TiO 2 (defined as FTO) film with high photocatalytic activity was developed using titanium- n -butoxide and NH 4 F as TiO 2 and fluorine precursors under mild condition, i.e. low temperature (lower than 373 K) and ambient pressure. The prepared samples were characterized by XRD, SEM, X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectrum (DRS), photoluminescence spectrum (PL) and TG–DSC analysis. The photocatalytic activity was evaluated by decomposing X-3B under artificial solar light. The results showed that the crystallinity of TiO 2 was improved by F-doping. F − ions can prevent the grain growth, and the transformation of anatase to rutile phase was also inhibited. The doped fluorine atoms existed in two chemical forms, and the ones incorporated into TiO 2 lattice might take a positive role in photocatalysis. Compared with surface fluorination samples, FTO film exhibited better photocatalytic activity. The high photocatalytic activity of FTO may due to extrinsic absorption through the creation of oxygen vacancies rather than the excitation of the intrinsic absorption band of bulk TiO 2 . Furthermore, the FTO can be recycled with little photocatalytic activity depression. Without any further treatment besides rinsing, after 6 recycle utilization, the photocatalytic activity of FTO film was still higher than 79%.