Modification Of TiO2 Research Articles

TiO2-modified MoS2 monolayer films enable sensitive NH3 sensing at room temperature.

The research and development of high-performance NH3 sensors are of great significance for environment monitoring and disease diagnosis applications. Two-dimensional (2D) MoS2 nanomaterials have exhibited great potential for building room-temperature (RT) NH3 sensors but still suffer from relatively low sensitivity. Herein, the TiO2-modified monolayer MoS2 films with controllable TiO2 loading contents are fabricated by a facile approach. A remarkable enhancement in the RT NH3 sensing performance is achieved after the n-n hetero-compositing of the TiO2/MoS2 system. The device with 95% surface coverage of TiO2 shows enhanced sensor response, low detection limit (0.5 ppm), wide detection range (0.5-1000 ppm), good repeatability, and superior selectivity against other gases. In situ Kelvin potential force microscopy results revealed that the TiO2 modification not only improved the surface reactivity of the sensing layers but also contributed to the NH3 sensing performance by serving as the "gas-gating" layers that modulated the electron depletion layer and the conductivity of the MoS2 films. Such an n-n hetero-compositing strategy can provide a simple and cost-effective approach for developing high-performance NH3 sensors based on 2D semiconductors.

Synergistic material modification-induced optimization of interfacial charge transfer and surface hydrogen adsorption.

Being chemically stable, low cost and made from abundant resources, titanium dioxide (TiO2) possesses the most desired advantages for photocatalytic applications. However, the intrinsic limits of high surface hydrogen adsorption energy, wide band gap, low separation rate and rapid recombination of the photogenerated charge carriers greatly hamper its utilization. To address these issues, the present work combines density functional theory (DFT) calculations with rational modifications of TiO2 with nickel doping and an ultra-thin shield of fluorinated carbon (FNT) for application in the photocatalytic hydrogen evolution reaction (HER). Comprehensive studies imply that the synergistic modifications not only optimize the surface H adsorption, but also facilitate the interfacial charge transfer and simultaneously prevent the photochemical and chemical corrosion of the catalysts. In good agreement with the theoretical predictions, the resulting FNT photocatalysts demonstrate an optimal HER efficiency of 13.0 mmol g-1 h-1, nearly 33-times and over three-times beyond that of the pristine TiO2 (0.4 mmol g-1 h-1) and the Ni-doped TiO2 (4.2 mmol g-1 h-1), respectively. Moreover, the composite also exhibits excellent stability with a well-reproducible HER performance over a 66-hour cyclic HER test of 15 cycles.

The effect of cetyltrimethylammonium bromide (CTAB) addition on green synthesis of porous N-doped TiO2 for photoreduction of heavy metal ion Cr(vi).

In this study, porous TiO2 photocatalysts modified by nitrogen (NCT) were successfully synthesized using a combination of green synthesis methods by utilizing Aloe vera (L.) Burm. f. peel and hydrothermal method. In addition, TiO2 was modified by increasing the active surface area using Cetyltrimethylammonium Bromide (CTAB). The X-ray Diffraction (XRD) results indicated that the anatase phase was formed. The result of the Diffuse Reflectance Spectroscopy UV-Vis (DRS UV-Vis) using the Tauc-plot method showed that all porous N-doped TiO2 samples experienced a decrease in the energy gap. This indicates the successful modification of TiO2 by nitrogen, as confirmed by the Fourier Transform Infra-Red (FTIR) result. Field Emission Scanning Electron Microscopy (FESEM) result showed that the synthesized TiO2 had a spherical morphology of 10-30 nm diameter. The Braunauer, Emmett, and Teller (BET) result indicated that the type IV isotherm curve with a mesoporous structure was formed. The NCT0.75 sample had a surface area and pore size of 95.02 m2 g-1 and 8.021 nm, respectively, while the NTi0.75 sample had a surface area and pore size of 90.97 m2 g-1 and 5.161 nm, respectively. The photocatalytic activity of the porous N-doped TiO2 was tested on photoreduction of metal pollutant model Cr(vi). The result demonstrated that the NCT0.75 sample had the most optimal photocatalytic activity by reducing 89.42% of Cr(vi) metal ions.

Metal-Doped TiO2 Thin Film as an Electron Transfer Layer for Perovskite Solar Cells: A Review

The electron transfer layer (ETL) plays a vital role in achieving high-performance perovskite solar cells (PSCs). Titanium dioxide (TiO2) is primarily utilised as the ETL since it is low-cost, chemically stable, and has the simplest thin-film preparation methods. However, TiO2 is not an ideal ETL because it leads to low conductivity, conduction band mismatch, and unfavourable electron mobility. In addition, the exposure of TiO2 to ultraviolet light induces the formation of oxygen vacancies at the surface. To overcome these issues, doping TiO2 with various metal ions is favourable to improve the surface structure properties and electronic properties. This review focuses on the bulk modification of TiO2 via doping with various metal ions concentrations to improve electrical and optical properties, charge carrier density, and interfacial electron–hole recombination, thus contributing to enhancing the power conversion efficiency (PCE) of the PSCs.

Impact of TiO2 Reduction and Cu Doping on Bacteria Inactivation under Artificial Solar Light Irradiation.

Preparation of TiO2 using the hydrothermal treatment in NH4OH solution and subsequent thermal heating at 500-700 °C in Ar was performed in order to introduce some titania surface defects. The highest amount of oxygen vacancies and Ti3+ surface defects were observed for a sample heat-treated at 500 °C. The presence of these surface defects enhanced photocatalytic properties of titania towards the deactivation of two bacteria species, E. coli and S. epidermidis, under artificial solar lamp irradiation. Further modification of TiO2 was targeted towards the doping of Cu species. Cu doping was realized through the impregnation of the titania surface by Cu species supplied from various copper salts in an aqueous solution and the subsequent heating at 500 °C in Ar. The following precursors were used as a source of Cu: CuSO4, CuNO3 or Cu(CH3COO)2. Cu doping was performed for raw TiO2 after a hydrothermal process with and without NH4OH addition. The obtained results indicate that Cu species were deposited on the titania surface defects in the case of reduced TiO2, but on the TiO2 without NH4OH modification, Cu species were attached through the titania adsorbed hydroxyl groups. Cu doping on TiO2 increased the absorption of light in the visible range. Rapid inactivation of E. coli within 30 min was obtained for the ammonia-reduced TiO2 heated at 500 °C and TiO2 doped with Cu from CuSO4 solution. Photocatalytic deactivation of S. epidermidis was greatly enhanced through Cu doping on TiO2. Impregnation of TiO2 with CuSO4 was the most effective for inactivation of both E. coli and S. epidermidis.

Modification of TiO2 by Er3+ and rGO enhancing visible photocatalytic degradation of arsanilic acid.

As a typical wide band gap photocatalyst, titania (TiO2) cannot use the visible light and has fast recombination rate of photogenerated electron-hole pairs. Simultaneous introduction of erbium ion (Er3+) and graphene oxide (rGO) into TiO2 might overcome these two drawbacks. In this study, Er3+ and rGO were co-doped on TiO2 to synthesize Er3+-rGO/TiO2 photocatalyst through a two-step sol-gel method. Based on the UV-visible diffuse reflectance spectra and photoluminescence spectrum, the introduction of Er3+ and rGO increased the visible light absorption efficiency and enhanced the migration of photogenerated electron. Pure TiO2 has almost no photocatalytic activity for arsanilic acid (p-ASA) degradation under visible light irradiation. However, while doping with 2.0mol% Er3+ and 10.0mol% rGO, the p-ASA could be completely degraded within 50min by the Er3+-rGO/TiO2 photocatalyst under visible light irradiation, and most of produced inorganic arsenic was in situ removed by adsorption from the solution. The reactive oxygen species (ROS) reacting with p-ASA was determined and superoxide radical (O2•-) and singlet oxygen (1O2) were the dominant ROS for the oxidation of p-ASA and arsenite. This work provides an approach of introducing Er3+ and rGO to enhance the visible light photocatalytic efficiency of TiO2.

High Nitrile Yields of Aerobic Ammoxidation of Alcohols Achieved by Generating •O2– and Br• Radicals over Iron-Modified TiO2 Photocatalysts

Catalytic ammoxidation of alcohols into nitriles is an essential reaction in organic synthesis. While highly desirable, conducting the synthesis at room temperature is challenging, using NH3 as the nitrogen source, O2 as the oxidant, and a catalyst without noble metals. Herein, we report robust photocatalysts consisting of Fe(III)-modified titanium dioxide (Fe/TiO2) for ammoxidation reactions at room temperature utilizing oxygen at atmospheric pressure, NH3 as the nitrogen source, and NH4Br as an additive. To the best of our knowledge, this is the first example of catalytic ammoxidation of alcohols over a photocatalyst using such cheap and benign materials. Various (hetero) aromatic nitriles were synthesized at high yields, and aliphatic alcohols could also be transformed into corresponding nitriles at considerable yields. The modification of TiO2 with Fe(III) facilitates the formation of active •O2- radicals and increases the adsorption of NH3 and amino intermediates on the catalyst, accelerating the ammoxidation to yield nitriles. The additive NH4Br impressively improves the catalytic efficiency via the formation of bromine radicals (Br•) from Br-, which works synergistically with •O2- to capture H• from Cα-H, which is present in benzyl alcohol and the intermediate aldimine (RCH═NH), to generate the active carbon-centered radicals. Further, the generation of Br• from the Br- additive consumes the photogenerated holes and OH• radicals to prevent over-oxidation, significantly improving the selectivity toward nitriles. This amalgamation of function and synergy of the Fe(III)-doped TiO2 and NH4Br reveals new opportunities for developing semiconductor-based photocatalytic systems for fine chemical synthesis.

Photocatalytic Treatment of Emerging Contaminants with Ag-Modified Titania—Is There a Risk Arising from the Degradation Products?

Bisphenol A, bisphenol S, and fluconazole are environmental contaminants widely found in surface waters because of their extensive usage and low biodegradability. Therefore, other methods are often considered for the removal of these compounds. The present study aims at their photodegradation with the use of UV light and three different catalysts, ZnO, TiO2, and Ag-TiO2. The results obtained show that photocatalytic removal of these compounds is also problematic and the use of catalysts, such as ZnO and TiO2, at increasing concentrations mostly leads to lower degradation of the tested compounds. The modification of TiO2 with silver increases the degradation of both bisphenols up to 100%, which was achieved in 60 min by bisphenol A and in as little as 10 min by bisphenol S. Nevertheless, the degradation of fluconazole remained at the same level, not exceeding 70% in 60 min, i.e., still much lower than expected. In addition, the degradation products of bisphenols show the hydroxylation and destruction of their phenolic rings, while no degradation products were found during the test with fluconazole. Although the potentially genotoxic bisphenol A degradation product was found, the acute toxicity of the formed compounds differs little in comparison to the parent bisphenols.

Visible-Light-Active N-Doped TiO2 Photocatalysts: Synthesis from TiOSO4, Characterization, and Enhancement of Stability Via Surface Modification

This paper describes the chemical engineering aspects for the preparation of highly active and stable nanocomposite photocatalysts based on N-doped TiO2. The synthesis is performed using titanium oxysulfate as a low-cost inorganic precursor and ammonia as a precipitating agent, as well as a source of nitrogen. Mixing the reagents under a control of pH leads to an amorphous titanium oxide hydrate, which can be further successfully converted to nanocrystalline anatase TiO2 through calcination in air at an increased temperature. The as-prepared N-doped TiO2 provides the complete oxidation of volatile organic compounds both under UV and visible light, and the action spectrum of N-doped TiO2 correlates to its absorption spectrum. The key role of paramagnetic nitrogen species in the absorption of visible light and in the visible-light-activity of N-doped TiO2 is shown using the EPR technique. Surface modification of N-doped TiO2 with copper species prevents its intense deactivation under highly powerful radiation and results in a nanocomposite photocatalyst with enhanced activity and stability. The photocatalysts prepared under different conditions are discussed regarding the effects of their characteristics on photocatalytic activity under UV and visible light.

The role of titanium dioxide surface modification on UV protective properties of eco-friendly PA coating

The aim of this work is to prepare polyacrylate emulsions (PA) with the addition of modified titanium dioxide (TiO2) nanoparticles. The modifiers used in this work are the nonionic emulsifier TX-100, the cationic initiator AIBA, the silane AMPTS, and the trisilanol POSS. The results show that particles with a larger hydrodynamic diameter are formed by the addition of modified fillers and that the viscosity of the PA emulsion increases significantly due to the modification of the TiO2 surface. The morphology indicates poorer dispersibility and distribution of the modified fillers in the polymer compared to coating with unmodified fillers. The thermal stability of PA is significantly increased by the addition of modified TiO2 nanoparticles. The results have also shown that the modification of TiO2 with AMPTS increases the UV absorbing ability of TiO2, while the modification with other modifiers enhances the photocatalytic effect of TiO2.

Synthesis of visible-light-driven photocatalyst of TiO2 modified waste red mud and its application in tetracycline hydrochloride removal

Solid waste red mud (RM) was used as a raw material to obtain a composite of TiO2/RM in a green and feasible method, and the prepared catalysts exhibited excellent performance in removing tetracycline hydrochloride (TC) under visible light. The results showed that after the modification of TiO2 on the surface of RM, the catalyst still preserved a narrow band gap similar to that of RM; the photocurrent response of the prepared catalysts was significantly improved. In the photodegradation of TC, because of the lower electron transfer resistance and the promoted carrier separation, TiO2/RM showed much better performance than RM or TiO2. The catalysts also exhibited high anti-interference ability and long-term stability in the photocatalysis process. The possible catalytic mechanism of the prepared catalysts under visible light and the TC degradation pathways are presented. Toxicity assessment by cyanobacteria certified that the toxicity of TC was greatly weakened. These results demonstrate that hazardous industrial waste RM, globally produced in large amounts, could be effectively utilized in producing environmentally friendly catalysts for removing organic pollutants by using visible light.

Photocatalytic hydrogen generation using TiO2: a state-of-the-art review

Abstract This review is focusing on photocatalytic hydrogen (H2) production as a viable fuel. The limitations of different production methods for H2 generation and the importance of photocatalytic process are discussed, which renders this process as highly promising to meet the future energy crises. TiO2 is one of most effective material to generate the H2 via photocatalytic processes. Therefore, advantages of the catalyst over other semiconductors have been thoroughly analyzed. Starting from synthesis of TiO2 and factors affecting the whole process of photocatalytic H2 production have been discussed. Modifications for improvement in TiO2 and the photocatalytic reaction are critically reviewed as well as the mechanism of TiO2 modification has been described. Metal doping, non-metal doping, impurity addition and defect introduction processes have been analyzed and the comparison of experimental results is developed based on H2 production efficiency. A critical review of the literature from 2004 to 2021 concludes that H2 production as fuel using TiO2 photocatalytic method is efficient and environment friendly, which have potential for practical applications for H2 generation.

The Role of Nitrogen-Doped TiO2 Supported by Platinum Catalyst Synthesized via Various Mode Preparations for Photocatalytic Enhancement.

The limitations of TiO2 as a photocatalyst such as the larger bandgap energy, which only activates under the UV region, give a lower photocatalytic activity. This study reports the role of the N and Pt co-dopant on the modification of the TiO2 photocatalyst for photocatalytic degradation of methylene blue dye under different mode preparations, i.e., sequential and vice-versa modes. The sequential mode preparation of the N and Pt co-dopant TiO2 photocatalyst consisted of the initial preparation of the N-doped TiO2 (N-TiO2) under the calcination method, which was then further doped with platinum (Pt) through the photodeposition process labeled as NPseq-TiO2, while the vice-versa mode was labeled as PNrev-TiO2. About 1.58 wt.% of N element was found in the NPseq-TiO2 photocatalyst, while there was no presence of N element detected in PNrev-TiO2, confirmed through an elemental analyzer (CHNS-O) and (EDX) analysis. The optimum weight percentage of Pt for both modes was detected at about ±2.0 wt.%, which was confirmed by inductively coupled plasma-emission spectroscopy (ICP-OES). The photoactivity under methylene blue (MB) dye degradation of the NPseq-TiO2 photocatalyst was 2 and 1.5 times faster compared to the unmodified TiO2 and PNrev-TiO2, where the photodegradation rates were, ca., 0.065 min-1 and 0.078 min-1, respectively. This was due to the N elements being incorporated with the TiO2 lattice, which was proven by UV-Vis/DRS where the bandgap energy of NPseq-TiO2 was reduced from 3.2 eV to 2.9 eV. In addition, the N generated a stronger PL signal due to the formation of oxygen vacancies defects on the surface of the NPseq-TiO2 photocatalyst. The higher specific surface area as well as higher pore volume for the NPseq-TiO2 photocatalyst enhanced its photocatalytic activity. Moreover, the NPseq-TiO2 showed the lowest COD value, and it was completely mineralized after 7 h of light irradiation. The preparation order did not affect the Pt dopant but did for the N element. Therefore, it is significant to investigate different mode preparations of the N and Pt co-dopant for the modification of TiO2 to produce a good-quality photocatalyst for photocatalytic study under the photodegradation of MB dye.

A comprehensive review of hydrogen generation by water splitting using 2D nanomaterials: Photo vs electro-catalysis

Transition metal carbides/nitrides (MXenes) with eccentric properties are emerging 2D nanomaterials with intriguing applications in the photo and electro-catalytic water splitting (Wsp). MXenes have a regular planer structure with a large specific surface area (SSA), excellent hydrophilicity, metallic conductivity, and a wide range of functionalities and surface termination groups, making them a promising candidate for long-term hydrogen generation (H2, gen). As a result, their use as electro and photo-catalysts in Wsp to solve energy and environmental challenges has increased. MXenes were proposed to overcome major drawbacks of TiO2, the most commonly used photo-catalyst in solar-driven Wsp, such as high band gap and fast recombination of photo-induced charge carriers. MXene has been rigorously investigated based on TiO2 modification (i.e. in-situ derived MXene-TiO2 and MXene/TiO2 nanocomposite) as well as Metal-MXene co-catalyst that provides simple electron channelization to improve overall electro and photo-catalytic activity (CatA)toward Wsp and increase the hydrogen evolution reaction (HER). However, several issues must be resolved before practical applications may be considered, such as weak environmental capabilities and limited intrinsic catalytic activities. Although there have been a few review papers on the synthesis, properties, and applications of Mxenes in various fields, this present work focuses on the most current advances in the synthetic of MXene-derived TiO2 and MXene/TiO2 nanohybrid composites as well as Metals-MXene nanocomposite, clarifying the charge carrier separation mechanism in connection to the formed Schottky junction at MXene- elements interface to attaining high photo-catalytic H2, gen. Furthermore, technical challenges, and enhanced catalytic performance as well as materials design and MXenes derivative with structural features and activity were presented. MXenes' catalytic mechanism is carefully outlined, along with its photocatalytic and electrocatalytic Wsp properties. According to the literature review, Ti3C2 can be combined with a variety of materials to produce electro or photo-catalysis with distinct layered morphology (0D, 1D, 2D, 3D), abundant surface termination groups, and enhanced photo-electrical activities. MXene-derived TiO2 and MXene/TiO2 nanohybrid composites have been proposed as viable electro and photo-catalytic H2, gen alternatives. The photo-catalytic H2, gen rate from Wsp over MXene-derived TiO2 can range from 20 to 50, 000 mol.g-1h−1, with Co-Chl@Ti3C2Tx producing the most.

Enhanced Cl– electrosorptive performance of activated carbon fibre via modification by TiO2 and polyaniline

Chloride ions in reclaimed water are the main contributors to corrosion of pipelines. In this study, titanium dioxide (TiO2)-and polyaniline (PANI)-modified activated carbon fibre (ACF) electrodes were prepared using the sol–gel method and in situ polymerisation, and their Cl– electrosorptive performance in simulated reclaimed water was extensively investigated. The prepared materials were characterised using X-ray diffraction, scanning electron microscopy, N2 adsorption, and Fourier-transform infrared spectroscopy. The experimental results indicated that the optimal Cl– removal rate from the ACF/TiO2/PANI electrode reached 85.34% when the calcination temperature of TiO2 was 400 °C and the polymerisation concentration of PANI was 0.02 mol·L−1. This study demonstrated that the ACF/TiO2/PANI electrode showed an excellent equilibrium adsorption capacity of 17.1 mg·g−1, which was 1.4 times that of the parent ACF. The superior performance was attributed to the modification of TiO2 and PANI, which considerably improved the hydrophilicity, conductivity, and physical adsorption capacity of the electrode. Consequently, the electrosorption rate and adsorption capacity were enhanced. In addition, the prepared ACF/TiO2/PANI electrode exhibited a high Cl– removal rate of 80.42% (adsorption capacity of 16.88 mg·g−1) in actual reclaimed water. Based on these results, the electrosorption kinetics and mechanism of the prepared ACF/TiO2/PANI electrode were analysed further.

The Significance of Organometallic Complexes in the Photochemical Reduction of Cu2+ Onto Semiconductor Scaffolds

Metal-metal oxide nanoparticles (MMO-NP) show promise as an alternative to diffusive topical antibiotics as they are capable of slowly releasing metal ions upon contact-activated oxidation which promotes toxicity to prokaryotes. Modification of semiconducting nanoparticles with metals also has great relevance in terms of increasing the photocatalytic activity of the particles, which are inherently limited in practicality due to their large band gap energies. The use of semiconductor nanoparticles for the reduction of metal ions has been widely explored, however, more work needs to be done to make the reduction of metal ions like Cu2+ more facile. This work will focus on the mechanism and efficacy of incorporating Cu2+ into organometallic complexes for the photoreduction of Cu2+ on the surface of TiO2 and ZnO. The mechanistic contribution of bidentate complexes of Cu2+ in the complete reduction of Cu2+ will be explored. The implementation of L-serine (SER), L-arginine (ARG), and glucono-delta-lactone (GDL) as ligands will be observed. Initial results show that the coordination of Cu2+ into an organometallic complex provides an effective medium for the delivery of Cu2+ to the surface of TiO2. Spectroscopic analysis will be used to determine if the ligands contribute to the two-electron reduction via ligand to metal charge transfer (LMCT) or via non-covalent interactions that increase the effective concentration of Cu2+ at the nanoparticle surface. The surface modification of TiO2 will be observed post-reaction with scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and atomic absorption spectroscopy (AAS) to measure copper content on the surface. Antimicrobial effectiveness will be characterized via Kirby Bauer testing as well as single cell optical imaging, with E. coli being the model microbe. Photocatalytic activity will be observed via the degradation kinetics of model pollutants. Preliminary results indicate that the addition of ligands greatly increased the yield of reduced copper at low pH and that there is some extent of control over the copper ion leaching as Kirby Bauer tests showed no zones of inhibition.

Functionalization of TiO2 for Better Performance as Orthopedic Implants.

This review mainly focuses on the surface functionalization approaches of titanium dioxide (TiO2) to prevent bacterial infections and facilitate osteointegration simultaneously for titanium (Ti)-based orthopedic implants. Infection is one of the major causes of implant failure. Meanwhile, it is also critical for the bone-forming cells to integrate with the implant surface. TiO2 is the native oxide layer of Ti which has good biocompatibility as well as enriched physical, chemical, electronic, and photocatalytic properties. The formed nanostructures during fabrication and the enriched properties of TiO2 have enabled various functionalization methods to combat the micro-organisms and enhance the osteogenesis of Ti implants. This review encompasses the various modifications of TiO2 in aspects of topology, drug loading, and element incorporation, as well as the most recently developed electron transfer and electrical tuning approaches. Taken together, these approaches can endow Ti implants with better bactericidal and osteogenic abilities via the functionalization of TiO2.

Palladium-modified TiO2 films in a photocatalytic microreactor: evaluation of radiation absorption properties and pollutant degradation efficiency.

Pure (TiO2) and 0.1 nominal atomic percent of palladium-modified TiO2 (Pd-TiO2) films were synthesized via a sol-gel method and compared through their physicochemical properties and photocatalytic activity in the degradation of an emerging contaminant, 17-α-ethinylestradiol (EE2). The activity of the films was studied using a continuous flow, planar microreactor under simulated sunlight. Catalysts characterization included X-ray diffraction, UV-Visible diffuse reflectance and transmittance spectroscopy, atomic force microscopy, transmission electron microscopy, Raman spectroscopy, N2 physisorption analysis, and X-ray photoelectron spectroscopy. The modification of TiO2 with palladium confined the size of anatase phase crystallites, increased the specific surface area and improved radiation absorption. PdO domains on TiO2 were observed. In all the tested conditions, higher conversion of EE2 was achieved with the Pd-TiO2 film compared with the TiO2 film, presenting an 80% increase in the reaction rate. The performance of the catalytic films was also assessed by the calculation of two efficiency parameters: radiation absorption efficiency and quantum efficiency of reaction. The Pd-TiO2 film showed a notable enhancement of the absorption of the incident radiation and a more efficient utilization of the absorbed photons to degrade the target pollutant.

Data-driven for accelerated design strategy of photocatalytic degradation activity prediction of doped TiO2 photocatalyst

TiO2 photocatalytic degradation, as an efficient, clean technology, is widely used in the treatment of contaminated wastewater. To expand the absorption spectrum of TiO2 from UV to visible light, considerable effort has been put into the modification of TiO2. Current TiO2 studies still rely on experimental work, mainly focusing on the effects of experimental variables on photocatalytic degradation. However, multiple variables introduce the experimental complexity and increase the cost. As a result, the development of TiO2 could be time-consuming and less cost-effective. Herein, we use a machine learning (ML) approach to study the photocatalytic degradation of doped TiO2. In this study, the degradation rate of pollutant solution in the presence of doped TiO2 is simulated under various experimental conditions using a LightGBM model. The training data from experiments comprised nine inputs, namely dopant, dopant/Ti molar ratio, calcination temperature, pollutant, catalyst/pollutant mass ratio, pH, experimental temperature, light wavelength and illumination time. The predicted result from trained model shows good accuracy with a coefficient of determination (92.8 %). The importance ranking of these variables, this study may help a better design of TiO2 for wastewater treatment, thereby improving the purification efficiency and saving natural resources.

Synthesis and characterizations of Ce2Zr2O7–TiO2 for increased photocatalytic activity toward degradation of methylene blue

Herein, novel Ce2Zr2O7–TiO2 was synthesized by the green method using Annona Squamosa L. peels extract (ASE). ASE contains alkaloids as hydrolyzing and capping agents for the formation of Ce2Zr2O7–TiO2. Various characterizations were conducted to elucidate the vibrational, optical, structural, morphological, elemental composition and photocatalytic properties of Ce2Zr2O7–TiO2. The photocatalytic activity of TiO2, Ce2Zr2O7, and Ce2Zr2O7–TiO2 was evaluated for methylene blue degradation under irradiated visible light. The degradation percentage using Ce2Zr2O7–TiO2 was higher than that of both TiO2 and Ce2Zr2O7. TiO2 modification with Ce2Zr2O7 increased the photocatalytic activity due to the increased light absorption in the visible region and a low electron-hole recombination rate. The reaction kinetics of methylene blue degradation over Ce2Zr2O7–TiO2 was found to be a pseudo-first-order rate with kapp value of = 1.1 × 10−2 min−1, which was around 4-fold higher than that of TiO2. Importantly, this research suggests the preparation of a novel TiO2-based photocatalyst with good photoresponse in the visible region for potential water treatment application.