Co-doped Anatase TiO2 Research Articles

Indium-free nonmetal and Nb co-doped anatase TiO2 transparent conductive oxide materials for photovoltaic applications: From first-principles calculations to macroscopic simulation

Various researchers have attempted to design indium-free transparent conductive materials. This study first employed density functional theory combined with the Hubbard U parameter to predict the photoelectric properties of nonmetal (B, C, N, F, P, and S) and Nb co-doped anatase TiO2. The results indicate that Ti0.875Nb0.125O1.96875N0.03125, Ti0.9375Nb0.0625O1.96875F0.03125, Ti0.875Nb0.125O1.96875P0.03125 and Ti0.9375Nb0.0625O1.96875S0.03125 possess characteristics of n-type semiconductors with high transmittance, exceptional thermal stability and wide bandgap. Notably, Ti0.9375Nb0.0625O1.96875S0.03125 exhibits optimal electronic conductivity due to its lower effective mass and higher electron concentration. Then, we used the SCAPS-1D solar cell simulation software to simulate the macroscopic characteristics of the MASnI3-based perovskite solar cell with Ti0.9375Nb0.0625O1.96875S0.03125 transparent conductive oxide layer based on the microscopic properties computed at the density functional theory level. A maximum efficiency of 27.17 % is obtained by regulating the thickness, electron affinity, and defect density of Ti0.9375Nb0.0625O1.96875S0.03125 layer and the thickness of MASnI3 absorber layer. The findings highlight the tremendous potential of Ti0.9375Nb0.0625O1.96875S0.03125 as an indium-free transparent conductive oxide candidate material for photovoltaic applications.

Regulation of photoelectric properties of multi-element (Sn, Fe, Ce) co-doped anatase TiO2: The first principles study

The energy band structure, density of states and optical properties of multi-element (Sn, Fe, Ce) co-doped anatase titanium dioxide have been calculated using the first principles method. The results show that two-element (Sn, Fe, Ce) doping affects the energy band structure more than the single doping behaviour. Co-doping of two of the three elements (Sn, Fe, Ce) reduced the energy band gap values of TiO2 compared to pure anatase TiO2.The forbidden bandwidths of Sn and Ce were smaller than those of mono-doped Sn, but the co-doped system had higher bandwidth narrowing than that of the mono-doped system. The co-doping of Sn and Ce is 0.206 eV smaller than the single doping of Sn, and the co-doping of Sn and Fe is 0.56 eV smaller than the single doping of Sn. The utilization of the regional light absorption is increased, and the absorption spectra are red-shifted. It can be seen that the co-doping method is more favourable to the improvement of visible light response and visible photocatalytic activity of TiO2 than the single doping method.

Electronic and photocatalytic properties of N, V co-doped anatase TiO2

Photocatalytic technology has good stability and ecological friendliness which is used to treat organic pollutants in wastewater. In this paper, TiO2, 1.5%V–TiO2 and N, V co-doped TiO2 were synthesized by hydrothermal method for photocatalytic degradation of tetracycline. Meanwhile, XRD, HRTEM, SEM, FT-IR, XPS, UV–Vis DRS, PL and electrochemistry tests were used to characterize the catalysts. The results showed that the appropriate amount of N, V co-doped can cause structural changes of TiO2. The co-doped of N and V enhanced the photocurrent response of TiO2, increased the specific surface area, reduced the band gap, and improved the efficiency of photodegradation of tetracycline. Accordingly, the tetracycline photocatalytic degradation path was proposed. 6%N-1.5%V–TiO2 completely degraded tetracycline into CO2, H2O and NO3−. The calculation results show that an appropriate amount of N, V co-doped TiO2 decreased bandgap, improved the optical absorption performance of TiO2. This work demonstrated the potential of N, V co-doped to design efficient photocatalysts.

A mesoporous Mo and N Co-doped TiO2 nanocomposite with enhanced photocatalytic efficiency.

This study reports the synthesis of a mesoporous Mo and N codoped anatase TiO2 nanocomposite with many oxygen vacancies using a simple one-step hydrothermal method and subsequent calcination treatment. Both Mo and N were effectively co-incorporated into the anatase phase of TiO2 without MoOx phase segregation. The codoped catalyst demonstrated a mesoporous architecture with a surface area of 107.48 m2 g-1 and a pore volume of 0.2974 cm3 g-1. X-ray photoelectron spectroscopy confirmed that both Mo and N dissolved in the TiO2 lattice and created induced oxygen vacancies. The interaction of the dopants (Mo and N) and oxygen vacancies clearly affected TiO2 crystal formation. Photocatalytic performance of the nanocomposite was investigated in terms of the decomposition of methyl orange at a concentration of 50 mg L-1 in an aqueous solution. The results revealed a significant methyl orange degradation of up to 99.6% after 30 min irradiation under a UV light. The impressive performance of the nanocomposite is assigned to the synergetic effect of important factors, including the co-doping of metallic (Mo) and non-metallic (N) elements, oxygen vacancy defects, bandgap, crystallite size, mesoporous structure, and BET surface area.

First-principles study of electronic properties of Zn and La doped and co-doped anatase TiO2

Ab initio computational modeling, based on Density Functional Theory, was employed to predict the influence of metal ions Zn2+ and La3+ on structural, electronic, and photocatalytic properties of anatase TiO2. Specifically, chemical modification of TiO2 was conducted by doping and co-doping the TiO2 using these ions. Properties of the chemically modified TiO2 were computationally predicted in terms of lattice parameters, electronic band structure, density of states, charge density, and absorption spectrum. It was found that co-doping TiO2 using Zn2+ and La3+ significantly reduced the bandgap and improved relative stability, and enhanced photocatalytic activity in the visible-light region was observed in comparison with pure TiO2. This research also interprets the underlying mechanism regarding why the doping and co-doping may have such influences on the properties of the chemically modified TiO2.

Density functional theory of Ca/F co-doped anatase TiO2

In order to understand the improved photocatalytic activity of Ca/F co-doped TiO2, the lattice parameters, energy band structures, density of states and absorption spectra of pure, Ca doped, F doped and Ca/F co-doped anatase TiO2 were calculated by first principles based on the density functional theory. It was found that the doping can result in lattice distortion of TiO2, especially the biggest lattice distortion was generated by the Ca/F co-doping. The forbidden energy band width of anatase TiO2 was broadened by Ca or F doping, while it was reduced by Ca/F co-doping. The calculated electronic density of states indicated that Ca doping provided contribution to the valence band of TiO2, and F doping resulted in the highest energy level occupied by electrons appeared in the conduction band. The energy band of TiO2 almost kept unchanged after Ca/F co-doping except the reduction of forbidden band width. Therefore, the experimentally obtained photocatalytic activity improvement of TiO2 co-doped with Ca and F may have resulted from the reduction of forbidden band width of TiO2.

Hydrogenation Influences on the Structural, Optical, and Insulating Properties of (Bi+Cr) Codoped Anatase TiO2 Nanoparticles

AbstractThis paper presents the investigation results for pure and (Bi/Cr) codoped TiO2 nanoparticles (NPs) synthesized by using a hydrothermal precipitation technique. The synthesized NPs are characterized by using X‐ray diffraction (XRD) and optical spectroscopy. The XRD patterns show a single anatase phase of an average nano‐crystallite size ≈6–9 nm. In addition, it was noticed that the hydrogenation of the NPs of the ceramic samples reduced the crystallite sizes due to the creation of O‐vacancies and microstrain. The optical absorption spectra show redshift of the bandgap. Moreover, an absorption hump in the high‐wavelength range of 630–800 nm is observed and attributed to the d‐d transitions in Cr3+ ions. Then, it is studied hydrogenation's significant effect on the absorption spectrum for λ > 370 nm, which attributes to the creation of a high density of point defects and structural microstrain that enhances the redshift of bandgap. The permittivity at 1 kHz of the prepared (Bi/Cr):TiO2 ceramic is found to be of large value (≈670), which is enhanced up to ≈103 by the hydrogenation. It is concluded that the hydrogenation in the present investigation supports the effects of the Bi3+ ions on the dielectric properties rather than that of Cr3+ ions, which mostly substitute the Ti ions (TiCr) due to the similarity of Ti3+ and Cr3+ ions. Thus, the measured dielectric constant of the hydrogenated sample [(Bi/Cr):TiO2‐H] is almost equal to that value of the host TiO2 doped with only Bi ions (Bi:TiO2). Moreover, it is concluded that the hydrogenation has a negligible effect on the effective polaron hopping energy, but increases the sample maximum barrier height (WM) by ≈55% causing an increase in the measured values of the permittivity.

Hydrogenation shrinks the colossal permittivity of Sb/Co co-doped TiO2 nanoparticles-structural and optical investigations

Pristine and (Sb/Co)-codoped TiO2 anatase powders were synthesized by hydrothermal method and some of the samples were hydrogenated. The samples were characterized by the traditional techniques: X-rays, optical diffuse reflection spectroscopy (DRS), and ac-electrical measurements. It was observed that the (Sb/Co) codoping induces the growth of the anatase. The optical absorption investigation was clarified by the generation of an intermediate band in the bandgap of TiO2. The catalysis power of the Co2+ ions to the adsorbed H2-dissociation strongly supports the optical absorption strength. The Sb5+/Co2+ codoping could generate weak colossal permittivity, which was lowered by ∼50% with hydrogenation. Such important results was studied and explained.

First-principles investigation on structural and photoelectric properties of (Nb, Ta) codoped anatase TiO2

The structural and photoelectric properties of (Nb, Ta) codoped anatase TiO2 were studied by first-principles calculations based on density functional theory and the Hubbard U correction. The results demonstrated that hybridized states composed of Ta 5d and Nb 4d orbitals at the bottom of the conduction band enabled the Fermi level to enter the conduction band and facilitated (Nb, Ta) codoped anatase TiO2 to exhibit n-type metallic characteristics, and the conductivity of Ti0·875Nb0·0625Ta0·0625O2(I) is approximately 3.2 times that of Ti0·9375Nb0·0625O2. Noted that both conductivity and mobility decreased with the increase of the distance between impurity Nb and Ta atoms and the Nb doping concentration. Moreover, the calculated results of optical properties presented the shifts of the absorption edges towards the ultraviolet region, and (Nb, Ta) codoped anatase TiO2 possessed the high transmittance thanks to its low absorption and reflection of visible light.

First-principles assessments of the electronic, and magneto-optical characteristics of Fe–Mn co-doped anatase TiO2 for photo-catalysis applications

First principles modeling is conducted to scrutinize the structural, chemical, electronic structures, bonding character, and magneto-optical features of intrinsic or pure anatase TiO2, Fe or Mn single-atom doped, and Mn–Fe diatom co-doped anatase TiO2 systems, respectively. Herein, the spin-polarized density functional theory (DFT) concerted with the on-site Hubbard (U) correction scheme for the Coulomb interaction, is utilized for the exchange-correlation term, as the generalized gradient approximation (GGA)+U. The spin-polarized density of states of Mn mono-atom doped anatase TiO2 material indicated a magnetic semiconductor attribute for both down/up spin components. Conversely, the outcome spin-polarized density of states of both Fe-doped and Mn–Fe co-doped anatase TiO2 materials illustrated the emergence of an intermediate band behavior. Accordingly, three magnetic impurity bands are produced in Mn–Fe co-doped anatase TiO2, the first two spin-up bands are located just uppermost the valence states nearby the Fermi level and the third spin-up/down band is lying far from the Fermi level just below the minimum conduction band. Interestingly, the spin-polarized charge density displayed an orbital ordering between the O 2p-orbitals and 3d-orbitals of Mn–Fe doped diatoms in the host TiO2 anatase system. The valuable optical ingredients, such as the optical absorption coefficient, refractive index, reflectivity spectra, optical conductivity, and electron energy loss function, are inspected and discussed. Moreover, the optical absorption coefficient characteristics of the mono-doped Mn/Fe and Mn–Fe co-doped TiO2 anatase structure displayed a relocation in the absorption feature edges towards the visible electromagnetic radiation regime. This means that the induced impurity bands delineate the essential contributor for boosting the catalytic activity in the visible light. It is expected that the Fe–Mn co-doped anatase TiO2 system could be a compelling candidate for its ultimate use in the photo-catalysts or magnetic storage devices.

Novel environmental method for enhanced biodegradation of contaminated wastewater via immobilizing nanoparticles on a new bacterial strain isolated industrial textile

Biological processes comprising bacteria, fungi, yeast, and algae received increasing interest for dye degradation due to their cost-effectiveness and eco-friendly nature. Hence, the current study aims to investigate the ability of the photocatalytic performance of N–S co-doped anatase TiO2 (NSTO) nanoparticles immobilized on isolated industrial textile bacteria (ITB) for degradation of basic blue 41 (BB 41). To prove the effect of improving the surface area of NSTO, NSTO also was immobilized on glass balls (NSTO-GB). NSTO nanoparticles were synthesized using sol-gel methods, and characterization of NSTO and NSTO-GB were measured using SEM, TEM, XPS, and DLS analysis. The results showed that the average size of NSTO was 50–60 nm. Moreover, the morphology and surface microstructure of ITB and ITB-NSTO were determined by the SEM, XPS technique. According to the results, ITB has a rod structure, NSTO nanoparticles are placed on the surface of ITB. However, NSTO was attached to the surface of ITB with the hydroxyl group.The ITB-NSTO indicated a higher BB 41 degradation yield (99%) than pure NSTO (65%) and ITB (74%). The effect of different factors was evaluated on biodegradation by ITB-NSTO. The high biodegradation was obtained in ITB (10 mg), NSTO (50 mg), BB41 (50 ppm), and pH 11. The GC-Mass, LC-Mass, and FT-IR analysis, which monitored the BB 41 degradation efficiency, proved the degradation efficiency by 99%. In the following, the toxicities of BB 41 solution before and after degradation were accessed through the brine shrimp lethality assay (BSLA) and seed germination assay, which displayed a considerable reduction in BB 41 after degradation. Toxicity results exhibited that ITB-NSTO has potential for industrial application.

Accurate structural descriptor enabled screening for nitrogen and oxygen vacancy codoped TiO2 with a large bandgap narrowing

• An accurate structural descriptor to represent the doping configurations of N/V O -codoped anatase TiO 2 is constructed. • Machine learning assisted electronic properties screening for the optimal doping configurations is enabled by the structural descriptor. • Two types of doping configurations featured by a linear and corner-sharing TiO 5 N 1 /TiO 4 N 2 octahedron chain with a large bandgap narrowing are identified. • The spatial ordering of N-dopants has been uncovered as the intrinsic reason for a large bandgap narrowing in N/V O -codoped TiO 2 . Nitrogen (N) doping has been widely adopted to improve the light absorption of TiO 2 . However, the newly introduced N-2 p states are largely localized thus barely overlap with O-2 p states in the valence band of TiO 2 , resulting in a shoulder-like absorption edge. To realize an apparent overlap between N-2 p and O-2 p states, charge compensation between N 3− and O 2− via electron transfer from oxygen vacancies (V O ) to N dopants is one possible strategy. To verify this, in numerous doping configurations of N/V O -codoped anatase TiO 2 , we identified two types of V O position independent N-dopant spatial orderings by efficient screening enabled with a newly designed structural descriptor. Compared with others, these two types of the N-dopant spatial orderings are highly beneficial for charge compensation to produce an apparent overlap between N-2 p and O-2 p states, therefore achieving a large bandgap narrowing. Furthermore, the two types of the N-dopant spatial orderings can also be generalized to N/V O -codoped rutile TiO 2 for bandgap narrowing.

Theoretical investigation on un-doped and doped TiO2 for solar cell application

Enhancing solar cell efficiency is one of the most challenging and demanding topics for PV researchers. An ab initio study is done here on the structure of crystal, formation energies, electronic structure, the density of states, effective mass, and optical properties of pure and S-doped, Fe-doped, and Fe-/S-doped anatase TiO2. Co-doping causes a significant reduction in the bandgap, suppresses the charge carrier’s recombination rate, and shifted absorption spectra from UV to the visible region. Hence, co-doped anatase TiO2 with Fe and S is more favorable as a buffer layer of the solar cell compared to S-doped and Fe-doped TiO2. The forecasted values of all quantities will benefit researchers to examine these materials for further photovoltaic applications.

First Principle DFT + U Calculations for the Optoelectronic Properties of Cu and C-Cu co-doped TiO2 Anatase Model

The metal-cations and non-metal anions mono-doped titanium dioxide (TiO2) systems have shown limited success as an efficient photocatalyst for various photocatalytic applications. Instead, the co-doping of TiO2 with metal and non-metal dopants is transpired as an effective doping approach to reduce the wide bandgap of the TiO2 and harvest a greater amount of the visible solar spectrum. Herein, a computational study was systematically performed to develop an efficient carbon-copper (C-Cu) co-doped TiO2 anatase system and compared its optoelectronic characteristics with the copper (Cu) mono-doped TiO2 system. The structural properties simulated with Perdew–Burke–Ernzerhof assisted generalized gradient approximation (GGA + PBE) whereas the electronic and optical properties with Hubbard’s modified (GGA + U) approximation. The electronic band structure and density of states plots display reduced bandgap energy of 2.30 eV for the C-Cu co-doped TiO2 anatase model in comparison to Cu mono-doped TiO2 anatase model. Moreover, the absorption spectra display a redshift of the optical absorption edge up to 515 nm for the co-doped system. Overall, the DFT work provide clear insights and predictions that the C-Cu co-doped TiO2 anatase model has an efficient bandgap narrowing with a significant redshift of the optical absorption edge in comparison to Cu mono-doped TiO2 model.

Time-Dependent Density Functional Theory Calculations of N- and S-Doped TiO2 Nanotube for Water-Splitting Applications.

On the basis of time-dependent density functional theory (TD-DFT) we performed first-principle calculations to predict optical properties and transition states of pristine, N- and S-doped, and N+S-codoped anatase TiO nanotubes of 1 nm-diameter. The host O atoms of the pristine TiO nanotube were substituted by N and S atoms to evaluate the influence of dopants on the photocatalytic properties of hollow titania nanostructures. The charge transition mechanism promoted by dopants positioned in the nanotube wall clearly demonstrates the constructive and destructive contributions to photoabsorption by means of calculated transition contribution maps. Based on the results of our calculations, we predict an increased visible-light-driven photoresponse in N- and S-doped and the N+S-codoped TiO nanotubes, enhancing the efficiency of hydrogen production in water-splitting applications.

Mo-doped, Cr-Doped, and Mo–Cr codoped TiO2 thin-film photocatalysts by comparative sol-gel spin coating and ion implantation

Uniformly codoped anatase TiO2 thin films of varying (equal) Mo and Cr concentrations (≤1.00 mol% for each dopant) were fabricated using sol-gel spin coating and deposited on fused silica substrates. All films were annealed at 450 °C for 2 h to recrystallise anatase. Undoped anatase films have been subjected to dual ion implantation for the first time, using Mo, Cr, and sequential Mo + Cr at 1 × 1014 atoms/cm2. The films were characterised by GAXRD, AFM, SIMS, XPS, and UV–Vis and the performance was assessed by dye degradation. Despite the volumetric doping by sol-gel and the directional doping by ion implantation, neither method resulted in homogeneous dopant distributions. Both methods caused decreasing crystallinities and associated partial amorphisation. The XPS signal of the uniformly codoped films is dominated by undissolved dopant ions, which is not the case for the ion-implanted films. Increasing Ti valences are attributed to the fully oxidised condition of the Ti4+ ions that diffuse to the surface from Ti vacancy formation compared to the Ti valence of the bulk lattice, which contains Ti3+. Increasing O valence is attributed to the electronegativity of O2−, which is higher than that of Ti4+. Detailed structural mechanisms for the solubility and energetics mechanisms involve the initial formation of Mo and Cr interstitials that fill the two voids adjacent to the central Ti ion in the TiO6 octahedron, followed by integrated solid solubility (ISS) and intervalence/multivalence charge transfer (IVCT/MVCT). The sequential order of the last two is reversed for the two different doping methods. These two effects are likely to be the source of synergy, if any, between the two dopant ions. The photocatalytic performances of the uniformly codoped films are relatively poor and correlate well with the band gap (Eg). The performances of the ion-implanted films do not correlate with the Eg, where TiO2–Mo performs poorly but TiO2–Cr and TiO2–Mo–Cr outperform the undoped film. These results are interpreted in terms of the competition between the effects of Mo doping, which causes partial amorphisation and/or blockage of active sites, and Cr doping, which may cause Mo–Cr synergism, Cr-based heterojunction formation, and/or improved charge-carrier separation owing to the surface-deposition nature of ion implantation.

Structural, electronic and optical properties of S-doped, Sc-doped and Sc–S co-doped anatase TiO2: a DFT + U calculation

Defect formation energies, electronic structures and optical properties of non-metal S, lanthanide metal Sc-doped and Sc–S co-doped anatase TiO2 were systematically investigated via a GGA + U method based on density functional theory (DFT). The on-site Coulomb corrections were applied to both 3d orbitals of Ti atom (U Ti _3d ) and 2p orbitals of O atom (U O _2p ). The results show all doped TiO2 systems exhibit a certain degree of red-shift due to the presence of impurity levels in the bandgap; in particular, the S-doped and Sc–S co-doped TiO2 exhibit better light absorption properties in the visible light range than either pure or Sc-doped TiO2 . In addition, the positive synergistic effect between the Sc and S atoms not only expands the absorption edge, but also increases the light absorption coefficient in the visible region. As a result, the Sc–S co-doped anatase TiO2 shows the best optical absorption spectrum in all doping systems.

Electronic structure and optical properties of C-Pt codoped anatase TiO2 by first principles

The optical properties of TiO2 are changed while doped with impurity atoms. Among the crystal morphology of doped TiO2, systematical study of C-Pt codoped TiO2 influence on optical properties has never been reported. The paper made a systematical calculation of the band gap, density of states, optical properties for pure TiO2, doped C/Pt and codoped C-Pt anatase TiO2 according to first principle. It was shown that the structure of codoped C-Pt system is rather stable; the band gap of TiO2 was reduced; the impurity level of forbidden band is composed of C-2p and Pt-5d; red shift of optical absorption is produced and broaden to visible light region; the absorption power is improved dramatically. Among those three codoped systems, the optical properties red shift of Ti6Pt2O15C is the most obvious and optical absorption is the strongest.

New investigation of nanosized co-doped Gd-Sm anatase TiO2 structural, magnetic, optical, and first-principles study

For the time we investigated the structural, optical and magnetic properties of (Sm, Gd) co-doped TiO2 anatase nanoparticles, in addition to Sm-doped TiO2 anatase nanoparticles using sol–gel method. The X-ray diffraction confirmed the single phase of tetragonal anatase with space group I41/amd, where the crystallite size was found 7.2 nm and 8.8 nm for Ti0.99Sm0.01O2 and Ti0.99Sm0.005Gd0.005O2, respectively. The Fourier-transform infrared spectra showed the basic absorption bands in tetragonal anatase structure with a stretching vibration around 500 cm−1 assigned to Ti–O–M, M = (Gd, Sm). Raman spectroscopy demonstrated the presence of the six active vibrational modes for anatase TiO2. Scanning electron microscopy analysis revealed that the particles are spherical in nature and agglomerated. Energy-dispersive X-ray spectroscopy confirmed the high purity of the as-prepared materials. The UV–VIS analysis showed absorption in visible range, due to the electronic transition, which has been confirmed theoretically, also a slight decrease in the band gap was noticed compared to the pure TiO2 anatase. The magnetic measurements reveal the existence of weak ferro or ferrimagnetic behavior. In this work, it is the first time that experimental and theoretical results prove that rare earth ions are incorporated into the sites of the TiO2 lattice without the formation of separate phases. In addition, the experimental work carried out has revealed the importance of surface area, crystallinity, light absorption, the presence of oxygen vacancies and structural defects on the magnetic and more particularly optical properties with the highlighting of the intermediate energy level between the valence and conduction bands. This study was complemented by first-principles calculations to investigate the effects of doping anatase TiO2 with the rare-earth elements Sm and Gd on its structural, optical and magnetic properties.

Electronic and optical properties of mono and co-doped anatase TiO2: First principles calculations

Density functional theory-based calculations are adopted for clarifying the validity of mono-dopant (Co, Cr, B), co-dopant (Co/B, Cr/B), and oxygen deficiency on the photocatalytic activity of anatase TiO2. The crystal structure, formation energies, electronic, and optical properties are calculated in the framework of HSE06 hybrid functional. The impurity states appear in the band gap region, thus changing the electronic structures and resulting in red shift of the absorption edge in the defected systems. Furthermore, the main band gap is narrowed for all defected systems except for Co mono-doping and oxygen vacancy. The deep impurity states on mono-doping, could affect the recombination of photo-excited electron-hole pairs, while the charge separation efficiency could be enhanced on Cr/B co-doping by shallow receptor state. The calculated optical properties emphasize the enhanced absorption efficiency and the extended absorption edge to the visible light on Cr/B co-doping. The findings in this paper could suggest the Cr/B co-doped anatase TiO2 as a good photocatalyst with longer life of the photogenerated charge carriers.