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The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. An increase in the power of industries and vehicles leads not only to atmospheric pollution by-products of incomplete fuel combustion but also to various microscopic particles that form aerosols, which carry an obvious danger to human health and also pollute the buildings' facades. An environmentally friendly building material with a hybrid method "Nano-titania gradient" was developed. This method consists of forming a gradient of n-TiO2 particles concentration in the composite since the physical properties of the composite are always inextricably linked to the geometry. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide with the use of graphene oxide was proposed, which contributed to an increase in the overall photosensitivity. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning is completed after 3 h after the irradiation start. The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. Using the theory of percolation, the concentration range of the photocatalyst content was calculated. To facilitate the material, waste cellulose was introduced. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide (SS TiO2) with the use of graphene oxide was proposed. The analysis of the experimental-statistical models of the compressive strength shows that the optimum content of TiO2 was in the range from 0.8 to 1.1%, and cellulose from 0.4 to 0.8%, the optimum content of SS TiO2 was in the range from 0.7 to 1.1%, and cellulose from 0.4 to 0.8%. Analysis of the experimental and statistical model of the bending strength shows that the optimal content of TiO2 and SS TiO2 was in the range of 0.6 to 1.0%, and cellulose from 0.4 to 0.8%. When studying the structure of composites, it was found that titanium dioxide was sorbed on the surface of swollen cellulose fibers and remained there after the process of cement hydration. The effectiveness of the method of surface sensitization of titanium dioxide by combining it with graphene oxide was shown. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning was completed after 3 h after the irradiation start. [ABSTRACT FROM AUTHOR]

The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. An increase in the power of industries and vehicles leads not only to atmospheric pollution by-products of incomplete fuel combustion but also to various microscopic particles that form aerosols, which carry an obvious danger to human health and also pollute the buildings’ facades. An environmentally friendly building material with a hybrid method “Nano-titania gradient” was developed. This method consists of forming a gradient of n-TiO2 particles concentration in the composite since the physical properties of the composite are always inextricably linked to the geometry. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide with the use of graphene oxide was proposed, which contributed to an increase in the overall photosensitivity. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning is completed after 3 h after the irradiation start. The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. Using the theory of percolation, the concentration range of the photocatalyst content was calculated. To facilitate the material, waste cellulose was introduced. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide (SS TiO2) with the use of graphene oxide was proposed. The analysis of the experimental-statistical models of the compressive strength shows that the optimum content of TiO2 was in the range from 0.8 to 1.1%, and cellulose from 0.4 to 0.8%, the optimum content of SS TiO2 was in the range from 0.7 to 1.1%, and cellulose from 0.4 to 0.8%. Analysis of the experimental and statistical model of the bending strength shows that the optimal content of TiO2 and SS TiO2 was in the range of 0.6 to 1.0%, and cellulose from 0.4 to 0.8%. When studying the structure of composites, it was found that titanium dioxide was sorbed on the surface of swollen cellulose fibers and remained there after the process of cement hydration. The effectiveness of the method of surface sensitization of titanium dioxide by combining it with graphene oxide was shown. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning was completed after 3 h after the irradiation start.

Highlights • Pure and Ni2+ sensitized a-ZTO microcubes were synthesized. • HCHO sensing performance of 0.75 at% Ni2+ sensitized a-ZTO was optimized. • This method only requires simple experimental conditions and has high yield. Abstract The pure and Ni2+ sensitized monodisperse amorphous zinc tin oxide (a-ZTO) microcubes were synthesized via an in-situ precipitation method and subsequent wet impregnation. XPS results revealed that Ni2+ sensitization increased the relative content of chemisorbed oxygen and oxygen vacancies on the surface of a-ZTO microcubes. Compared to pure a-ZTO microcubes, 0.75 at% Ni2+ sensitized a-ZTO microcubes can significantly improve the gas sensing performance to formaldehyde at 200 °C, which may be attributed to its uniform morphology and modification of Ni2+ on the surface of a-ZTO microcubes. Further, the gas sensing mechanism is briefly discussed. [ABSTRACT FROM AUTHOR]

In this work, the surface of MoS2 particles has been coated with Ni using the electroless plating method as it is relatively efficient and cost effective. Two samples were synthesised, one of them was sensitized using Sn (ultrasonically dispersed for 30 min in a 24-hour aged bath comprising 0.1 M SnCl2 and 0.1 M HCl) and the other was not sensitized. The effect of the sensitization process on nickel coating over MoS2 particle surface was studied. XRD pattern of as-deposited surface of the sensitized and non-sensitized samples shows the absence of Ni phase while the annealed samples confirm the presence of Ni in fcc structural phase along with MoS2 phase. The surface morphology of all samples is observed using FESEM and it is observed that the treatment with Sn forms a uniform coating over MoS2 particles whereas the non-sensitized sample shows an irregular coating of Ni over MoS2 particles. [ABSTRACT FROM AUTHOR]

The surface sensitization is the key to prepare negative electron affinity photocathode. The thesis emphasizes on the study of surface sensitization mechanism of p-type doping GaN nanowires utilizing first principles based on density function theory. The adsorption energy, work function, dipole moment, geometry structure, electronic structure and optical properties of Mg-doped GaN nanowires surfaces with various coverages of Cs atoms are investigated. The GaN nanowire with Mg doped in core position is taken as the sensitization base. At the initial stage of sensitization, the best adsorption site for Cs atom on GaN nanowire surface is B N , the bridge site of two adjacent N atoms. Surface sensitization generates a p-type internal surface with an n-type surface state, introducing a band bending region which can help reduce surface barrier and work function. With increasing Cs coverage, work functions decrease monotonously and the “Cs-kill” phenomenon disappears. For Cs coverage of 0.75 ML and 1 ML, the corresponding sensitization systems reach negative electron affinity state. Through surface sensitization, the absorption curves are red shifted and the absorption coefficient is cut down. All theoretical calculations can guide the design of negative electron affinity Mg doped GaN nanowires photocathode. [ABSTRACT FROM AUTHOR]

[Display omitted] • BPQDs are prepared by a sonication-assisted liquid exfoliation method. • BPQDs sensitized g-C 3 N 4 photocatalyst is used in the degradation of PVA. • Accelerated flow of photoinduced electrons can occur from g-C 3 N 4 to BPQDs. • A Z-scheme charge transfer route is supposed for the photocatalytic process. • Theoretical results for electron transfer agree well with experiment tests. To address the pollution caused by polyvinyl alcohol (PVA) waste, a composite photocatalyst is developed by sensitizing g-C 3 N 4 with black phosphorus quantum dots (BPQDs) using a simple mechanical stirring method. Both g-C 3 N 4 and BPQDs are inorganic nonmetallic semiconductors with well-matched band positions, facilitating efficient photoinduced charge transfer. The periodic table's adjacent relationship between C, N and P elements allows easy formation of P-N or P-C bonds by replacing C or N atoms with P atoms. The resulting composite shows uniform decoration of two-dimensional layered g-C 3 N 4 with BPQDs with an average size of 2.2 nm. Under solar light simulator irradiation for 20 min, the composite photocatalyst exhibits significantly enhanced photocatalytic activity, with PVA degradation efficiency increasing from 27.1% (pure g-C 3 N 4) to 85.9%. Experimental results and density functional theoretical calculations suggest the formation of a Z-scheme route at the g-C 3 N 4 /BPQDs interface. This facilitates photoinduced electron transfer from g-C 3 N 4 to BPQDs, leading to improved carrier production and separation, reduced charge-transfer resistance, and accelerated PVA degradation. The proposed composite photocatalyst holds promise for addressing PVA pollution and improving environmental sustainability. [ABSTRACT FROM AUTHOR]

ZrO 2 could be an effective catalyst to motivate H 2 O 2 as green source to generate reactive oxygen species to implement mineralization or decomposition of pollutants. In this system, simultaneously achieving structure optimization and modification is very significance for the improvement of catalytic activity of materials. Here, ZrO 2 fibers with the porous structure and surface functionalization were prepared via combination of template and water vapor treatment. It was found that the addition of small amount of H 2 O 2 as green reactive oxygen species source could further increase the removal rate of minocycline hydrochloride (MC) or dyes in the system. And the adsorption and catalytic mechanisms were proposed considering the changes of adsorption interaction types due to the polarization of water vapor and the generation of oxidizing species with existence of H 2 O 2. This study would be valuable to promote the synthesis and design of 1D materials with highly efficient applications. [Display omitted] • Surface functionalized ZrO 2 fibers with high surface area were obtained by combination of template and water promotion. • ZrO 2 fibers exhibited efficient bi-functional adsorption and degradation properties for minocycline hydrochloride and dyes. • The as-prepared ZrO 2 fibers possessed a high capacity of 492.3 mg g−1 for minocycline hydrochloride. • Plausible adsorption and degradation mechanisms of ZrO 2 fibers were proposed in detail. [ABSTRACT FROM AUTHOR]

Highly ordered titanium dioxide nanotubes (TiO 2 NTs) were prepared by a low-temperature hydrothermal process with Ti sheet as precursor in NaOH solutions. Gold nanoparticles (Au NPs) were then deposited on the surface of TiO 2 NTs by a microwave-assisted chemical reduction route. The investigation reveal that the Au NPs are well dispersed on the surface of TiO 2 NTs in metallic state, and Au NPs can effectively promote the separation of photogenerated electron-hole pairs. Besides, Au NPs also can enhance the visible light absorption of TiO 2 NTs due to their localized surface plasmon resonance (LSPR) effect. The experimental results indicate that 0.5 Au/TiO 2 NTs film with an photocurrent of 19.0 μA/cm 2 exhibits the highest photoelectrocatalytic (PEC) activity, when under a low bias of 0.5 V, in the degradation of methylene blue (MB). Additionally, the mechanism for the enhanced PEC performance of Au/TiO 2 NTs is preliminarily discussed. The Au NPs decorated TiO 2 NTs displayed a more effective separation of photogenerated electron-hole pairs. The enhanced visible light absorption was owning to the Au NPs localized surface plasmon resonance (LSPR) effect. Finally, the mechanism for the enhanced PEC performance of Au/TiO 2 NTs was also proposed. [ABSTRACT FROM AUTHOR]

TiO 2 nanorod arrays (NRAs) were hydrothermally grown on transparent fluorine-doped tin oxide (FTO) substrates, and were converted into nanotubes (NTAs) by hydrothermally in situ etching. Ag nanoparticles (NPLs) were sensitized on the NRAs and NTAs by a simple photodeposition approach (products were denoted as Ag-TiO 2 NRAs and NTAs). The Ag-TiO 2 NTAs samples possessed a large specific surface area (116 m 2 g -1 ) with Ag NPLs homogeneously dispersed among the TiO 2 NTAs. The Ag-TiO 2 NTAs exhibited significantly enhanced photocatalytic activities (98.8%) in degradation of methyl orange (MO) compared to Ag-TiO 2 NRAs (92.6%), TiO 2 NTAs (86.2%), and NRAs (81.7%). The enhanced photocatalytic activities can be attributed to the large specific surface area of TiO 2 NTAs and strong surface plasmon resonance (SPR) of Ag NPLs. In addition, Ag-TiO 2 NTAs showed easy recovery feature in the recovery process and high durability in the recycling test, which was expected to be an efficient and practical photocatalyst used for waste water treatment. [ABSTRACT FROM AUTHOR]

Copper nanoparticles (NPs) deposited on the surface of self-organized highly ordered TiO 2 nanotube arrays (Cu/TiO 2 NTs) were synthesized by electrochemical anodization and the successive ionic layer adsorption and reaction technique. The morphology, elemental composition, crystallinity, light absorption ability and photoelectrochemical property of the as-prepared Cu/TiO 2 NTs electrode were distinguished based on various characterizations. X-ray photoelectron spectroscopy showed that the Cu NPs existed as Cu(II)O and Cu(I) 2 O on the TiO 2 surface. The current–voltage curve of Cu/TiO 2 NTs electrode indicated a rectifying behavior. The surface sensitization of TiO 2 NTs by CuO and Cu 2 O NPs enhanced the absorption of visible light. Meanwhile, the enhanced charge separation was demonstrated by electrochemical impedance spectroscopy, transient photocurrent response and photovoltage measurements. Besides, Cu/TiO 2 NTs electrode showed more effective photoconversion efficiency and enhanced photoelectrocatalytic activity towards the degradation of diclofenac than pure TiO 2 NTs electrode under simulated solar light irradiation, which was attributed to the synergistic effects between nanotubular structures of TiO 2 and uniformly dispersed copper nanoparticles, as well as the small bias potential. Furthermore, the photoelectrocatalytic mechanism was proposed and the possible radical species involved in the photoelectrocatalytic degradation of diclofenac were analyzed by active species trapping. The Cu/TiO 2 NTs electrode exhibited high reusability. [ABSTRACT FROM AUTHOR]

• Tin monoxide nanobelts were decorated with Pt and Pd nanoparticles for gas sensor application. • Pristine devices are both sensitive and selective for nitrogen dioxide between 100 and 250 °C. • Both Pd- and Pt-decorated devices present excellent selectivity to H 2 at 300 and 350 °C. • Pt-decorated sensor present good selectivity for high concentrations of CO (>200 ppm) at low temperatures (100 and 150 °C). • Electronic sensitization mechanism is elucidated based on the band diagram of materials. This work reports on the gas sensor response of undecorated 1D stannous oxide nanobelts and those decorated with Pt and Pd nanoparticles. The sensor device responses to H 2 , CO and NO 2 were measured in dry air baseline atmosphere as functions of the analyte concentration (1–1000 ppm) and temperature (100-350 °C). Noble metal decorated SnO devices exhibited enhanced chemical sensitization, resulting in increased sensitivity upon exposure to reducing gases at different working temperatures. Differences in enhancement levels are attributed to strong electronic sensitization effects that are dependent on the respective Pt and Pd work functions and the unique SnO band structure, characterized by a small band gap. Gas sensing results also showed superior selectivity to H 2 for metal-decorated nanobelts. Based on the findings in this work, we propose an array based on SnO structures capable of detecting and distinguishing reducing and oxidizing gases. [ABSTRACT FROM AUTHOR]

• Surface sensitization with P3TA has improved the visible light absorption of TiO 2 in nanohybrids. • Copper doping had effectively inhibited the electron-hole recombination and promoted the generation of OH radicals. • Presence of brookite phase is an additional benefit in easy transfer of charge carriers. • Malathion was photocatalytically degraded in 75 min under visible light irradiation. A series of heterogeneous poly 3-Thenoic acid (P3TA) sensitized, Copper (Cu) doped anatase/brookite TiO 2 (Cu-TiO 2) nanohybrid photocatalysts (P3TA/Cu-TiO 2) were facilely synthesized using modified sol-gel method by taking different weight percentages (wt%) of P3TA to TiO 2 at 20 °C temperature. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Ultraviolet-Visible diffuse reflectance spectroscopy (UV–vis DRS), Field emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDX), High resolution transmission electron microscopy (HRTEM) and Brunauer-Emmet-Teller (BET) surface area analyses were performed to characterize the as prepared nanohybrids and their photocatalytic performances were then investigated by degrading an organophosphorous pesticide (malathion) under visible light irradiation. The characterization results revealed that P3TA surface sensitization and Copper doping in TiO 2 lead to formation of agglomerated multi-particle nanohybrids with good thermal stability compared to pure TiO 2. The nanohybrids exhibited a strong and broad absorption in visible range, good adsorption capacity and enhanced photocatalytic activity indicated the narrowed bang gap, decreased particle size and increased surface area of TiO 2 nanoparticles. Surface chemical composition analysis showed the presence of the constituent elements of both the P3TA and Cu-TiO 2 nanoparticles confirmed the strong interfacial interaction between the P3TA and Cu-TiO 2 ,which further supported by FT-IR results. Photoluminescence and radical scavenger experiments confirmed that hydroxyl radicals (OH) are the main reactive species responsible for the oxidative degradation of malathion. Effects of different nanohybrid/malathion operating conditions on the photocatalytic activity were investigated and a simple plausible mechanism was proposed accordingly. [ABSTRACT FROM AUTHOR]