Tri-doped TiO2 Research Articles

Efficient photocatalytic removal of aqueous Cr(VI) by N-F-Al tri-doped TiO2

As chromium is a common heavy metal contaminant in water, we have prepared N-F-Al tri-doped TiO2 catalyst for Cr(VI) removal under visible light. The sample was prepared via a sol-gel method and was characterized by XRD, BET, UV-vis DRS, XPS and SEM techniques. In the photocatalytic experiments, effects of Al/Ti ratio, F/Ti ratio, calcination temperature and different dopants were investigated. The optimum Al/Ti molar ratio, F/Ti ratio and calcination temperature proved to be 0.01, 0.1 and 500 °C, respectively, which is in accordance with the characterization analysis. Catalysts prepared under this condition showed a high photoactivity for Cr(VI) removal in water.

Effect of co-doping and tri-doping with transition metals and a nonmetal on photocatalytic activity in visible light of TiO2 thin film

Mono, co- and tri-doped TiO2 thin films with the transition metals (vanadium and/or chrominium) and a nonmetal (nitrogen) have been fabricated by sol-gel method. X-ray diffraction results clearly reveal anatase crystal structure for all obtained samples and doping with any dopants doesn’t change the anatase phase of TiO2. Compared to TiO2, three types of doped TiO2 thin films exhibit a red-shift in the absorption edge and have much better photocatalytic properties for methylene blue degradation in visible light region. The maximum visible-photocatalytic performance was achieved for tri-doped TiO2 sample. The mechanism for enhancing visible-photocatalytic activity of co-doped and tri-doped TiO2 thin films was also examined.

Studies on up-converting Ho3+-Yb3+-F− tri-doped TiO2 nanoparticles for enhancing efficiency of dye-sensitized solar cells

Titanium dioxide (TiO2) nanoparticles (NPs) tri-doped with different concentrations of Ho3+, Yb3+ and F− ions (abbreviated as UC-F-TiO2 NPs) were synthesized for applications in dye-sensitized solar cells (DSSCs). These UC-F-TiO2 NPs were synthesized using hydrosol−hydrothermal method. The phase structure, morphology and luminescent property of UC-F-TiO2 NPs are characterized using X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and photoluminescence (PL) spectroscopy. The results indicated that the UC-F-TiO2 NPs are mixed phases of anatase and rutile with approximate sizes in the range from 10 to 15 nm. Photoluminescence (PL) measurements confirmed that the UC-F-TiO2 NPs have a good up-converting (UC) property. The prepared powders were used to make photo-anodes for DSSCs. The DSSCs assembled with a bilayer-structured UP-F-TiO2 NP photo-anode has a 15.2% enhancement in short-circuit current density and a 29.7% enhancement in conversion efficiency comparing with DSSCs assembled with un-doped TiO2 photo-anodes. The photocurrent improvement is due to an increase in the light-harvesting capacity of the photo-anodes attained through the up-converting property of UC-F-TiO2 NPs, which was demonstrated by PL and IPCE measurements. The result suggests that the incorporation of up-converting nanoparticles into photo-anode is an effective approach to improve the photovoltaic characteristics of DSSCs.

Sono-synthesis of solar light responsive S–N–C–tri doped TiO2 photo-catalyst under optimized conditions for degradation and mineralization of Diclofenac

C–N–S–tri doped TiO2 anatase phase was synthesized using a facile, effective and novel sonochemical method at low frequency (20kHz) and at room temperature. Titanium butoxide as the titanium precursor and thiourea as the dopant source were used in the synthesis of the photo-catalyst. The effects of important parameters such as thiourea/Ti molar ratio, ultrasound intensity, sonication time and temperature were studied on the synthesis of tri-doped TiO2. The XPS results confirmed the presence of N, S, and C in the photo-catalyst. The photo-catalytic efficiency of the synthesized catalyst was studied toward the removal of Diclofenac as a model pharmaceutical organic pollutant. The results confirmed that the photo-catalyst synthesized with narrower band gap energy, shorter sonication time and higher ultrasound intensity leads to a rapid removal of Diclofenac. The effect of operational variables on the photo-catalytic activity of C–N–S tri doped TiO2 nanoparticles was studied and optimized using the Taguchi method as a statistical technique. Additionally, the degradation process followed the pseudo-first-order kinetics model and the highest apparent rate constant of 0.0632min−1 achieved in 90min. Chemical oxygen demand (COD) analysis confirmed that the mineralization took place completely (100%) under the optimized conditions in 180min. Different scavengers were applied during the degradation process and active species such as OH and O2− had key roles in the photo-catalytic process.

Synthesis and up-conversion properties of Ho3+-Yb3+-F− tri-doped TiO2 nanoparticles and their application in dye-sensitized solar cells

A series of Ho3+-Yb3+-F− tri-doped TiO2 nanoparticles (abbreviated as UP-F-TiO2 NPs) were prepared using a hydrosol−hydrothermal method, and their phase structure, morphology and luminescent properties were investigated. These nanoparticles were utilized to prepare a photoanode of dye-sensitized solar cells (DSSCs). Based on the up-conversion spectra of UP-F-TiO2 NPs, an up-conversion mechanism is proposed. The results indicate that the UP-F-TiO2 NPs were a mixture of anatase and rutile nanoparticles, and the mass fraction of the anatase phase first increases and then decreases with increasing incorporation of F− ions into UC-F-TiO2 NPs, while the un-doped TiO2 nanoparticles are in the rutile phase. The average sizes of the UP-F-TiO2 NPs are estimated to be 10nm. The HRTEM shows clear lattice fringes with spacings of 0.347nm and 0.323nm that correspond to the d spacings of the (101) facets in anatase TiO2 and the (110) facets in rutile TiO2, respectively. Under the excitation of 980nm NIR light, the UP-F-TiO2 NPs exhibit a stronger emission band centered at 543nm and two relatively weaker bands located at 667nm and 751nm. The DSSC assembled with a bilayer-structured UP-F-TiO2 NP photoanode has a 35.2% enhancement in conversion efficiency compared with DSSCs assembled with un-doped TiO2 photoanodes.

Iridium, carbon and nitrogen multiple-doped TiO2 Nanoparticles with enhanced photocatalytic activity

The aim of this research is to enhance the photocatalytic activity of TiO2 nanoparticles for the UV–visible light by multiple-doping with Iridium, carbon and nitrogen. The tridoped TiO2 photocatalyst were prepared by wet chemical method, and characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible light diffuse reflection spectroscopy and room temperature photoluminescence spectroscopy. Besides, the photocatalytic H2 evolution performance of Ir-C-N tridoped TiO2 under UV–visible light irradiation was evaluated. It was found that Ir existed as Ir4+ by substituting Ti in the lattice of TiO2; meanwhile, C and N were also incorporated into the surface of TiO2 nanoparticles in interstitial mode. Meanwhile, Ir-C-N tridoping extended the absorption of TiO2 into the visible light region and narrowed its band gap to ~3.0eV, resulting in enhanced photocatalytic H2 evolution under UV–visible light irradiation. This could be attributed to narrow band gap and proper electronic structure of TiO2 after Ir-C-N tridoping.

Synthesis and characterization of Fe, N and C tri-doped polymorphic TiO2 and the visible light photocatalytic reduction of Cr(VI)

Abstract The (Fe, N and C) tri-coped polymorphic TiO2 (Fe-N-C-TiO2), containing anatase, rutile and brookite phase, were synthesized by a hydrothermal method. The tri-coped polymorphic TiO2 were characterized in detail by several techniques in terms of their structure, composition, optics, morphology, surface area, and so on. The photocatalytic activities of Fe-N-C-TiO2 nano-materials were examined under visible light illumination using Cr(VI) as target pollutant. The results showed that Fe/Ti weight ratio crucially determines the photocatalytic activity of Fe-N-C-TiO2 nano-materials. Fe-N-C-TiO2 nano-materials with Fe/Ti weight ratio of 0.30% exhibits highest photocatalytic activity than that of the other nano-materials under visible light irradiation, which can be attributed to the synergic effect of the higher BET surface area, separation rate of electron-hole pairs, more number of surface absorbed hydroxyl groups ( OH), stronger absorption in the visible-light region and optimum Fe/Ti weight ratio.

Synergetic effects of lanthanum, nitrogen and phosphorus tri-doping on visible-light photoactivity of TiO2 fabricated by microwave-hydrothermal process

Effects of La, N, and P doping on the structural, electronic and optical properties of TiO2 synthesized from TiCl4 hydrolysis via a microwave-hydrothermal process were investigated by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy, electron paramagnetic resonance, UV-vis absorbance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy. The results showed that the presence of La in the tri-doped TiO2 played a predominant role in inhibiting the recombination of the photogenerated electrons and holes. The existence of the substitutional N, interstitial N, and oxygen vacancies in TiO2 lattices led to the band gap narrowing. It was P-doping rather than La or N doping that played a key role in inhibiting both anatase-to-rutile phase transformation and crystal growth, in stabilizing the mesoporous textural properties, and in increasing the content of surface bridging hydroxyl. Moreover, the tri-doping significantly enhanced the surface Ti4+–O2––Ti4+–O−• species. All above-mentioned factors cooperated to result in the enhanced photoactivity of the tri-doped TiO2. As a result, it exhibited the highest photoactivity towards the degradation of 4-chlorophenol (4-CP) under visible-light irradiation among all samples, which was much superior to commercial P25 TiO2.

Ab initio studies of Nb–N–S tri-doped TiO2 with enhanced visible light photocatalytic activity

The electronic and optical properties of Nb–N–S tri-doped anatase TiO2 were investigated within the frame of the density functional theory (DFT) plus U method. Results show that a significant red-shift effect and improvement of visible-light absorption for Nb–N–S tri-doped TiO2 are observed with respect to pure TiO2 and S–N codoped TiO2. At the same time, the enhanced visible-light photocatalytic activity of tri-doped TiO2 is derived from the narrowing band gap, the appearance of Nb 4d state at the bottom of conduction band and the mixture of N 2p, S 3p states forming new defect levels at the top of valance band, which is excellently consistent with the previous experiment. Moreover, S ion leads to the lattice distortion and promotes the visible-light photocatalytic activity. Furthermore, the absorbance of 1.39NbNS–TiO2 accords well with the experimental result in the visible region. It is also found that the 2.78NbNS–TiO2 can be easily grown under O-rich condition and have the strongest absorbance from 2.0 to 4.2eV among four models.

Cooperation among N, F and Fe in tri-doped TiO2 photocatalyst

TiO2 photocatalysts tri-doped with N, F and Fe were synthesized by a sol–gel method. The cooperation of N, F and Fe in tri-doped TiO2 was verified by monitoring NH3 decomposition, X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet–visible (UV–Vis) absorption spectroscopy, and by the simulation based on the density functional theory (DFT). The results from NH3 decomposition revealed that the cooperation of N, F and Fe broadened the optical response of TiO2 to the visible light range and also enhanced the photocatalytic activity of TiO2 under UV light. The reusability of the tri-doped TiO2 sample after three cycles under UV and visible light irradiation was very good. XRD patterns and SEM and HRTEM images indicated that the tri-doped sample was nanometric anatase with a small amount of rutile with an average particle size of 18 nm. Tri-doping with N, F and Fe suppressed the phase transition from anatase to rutile and also resulted in some more lattice defects. XPS analysis showed that the N, F and Fe atoms were doped into the TiO2 lattice. UV–Vis absorption spectra of the tri-doped TiO2 showed that its optical absorption edge was moved up to 640 nm and its UV absorption was also enhanced. The DFT results confirmed that the cooperation of Fe 3d and N 2p orbits narrowed the band gap of TiO2 and the F 2p orbit broadened the upper valence bands. The synergistic electron density around N, F and Fe in tri-doped TiO2 was capable of enhancing the photochemical stability and reusability of TiO2.

Characterization and catalytic performance of B-doped, B–N co-doped and B–N–F tri-doped TiO2 towards simultaneous Cr(VI) reduction and benzoic acid oxidation

B-doped, B–N co-doped and B–N–F tri-doped TiO2 catalysts were prepared via a sol–gel method using H3BO3, NH4Cl and NH4F as B, N and N–F dopant precursors, respectively. N-doped, N–F co-doped and a pure TiO2 (undoped) samples were also prepared by the same method as blank samples, for comparison. The catalysts were evaluated for the simultaneous photocatalytic reduction of Cr(VI) and oxidation of benzoic acid (BA). XRD analysis shows the formation of pure TiO2 anatase phase in all cases, with crystallite size varying from 10.1nm to 14.6nm for all doped samples. UV–vis DRS spectra show narrowing of the band gap (Eg) for all doped samples, compared to the undoped TiO2. Concomitant presence of N and F ions i.e. in N–F co-doped and B–N–F tri-doped TiO2 catalysts, causes the most pronounced decrease of Eg while B–N co-doped and B–N–F tri-doped TiO2 have lower Eg values than mono B-doped but higher than N-doped and N–F co-doped TiO2. B and N doping also causes an increase of specific surface area and a decrease in mean pore diameter. Electron Paramagnetic Resonance (EPR) spectroscopy was employed for a detailed investigation of the structure and photoexcited species formed in these catalysts. The EPR data show that N-doping forms Nb photoexcited species which react as holes, Ti4+–O− oxygen vacancies (OVs) and Ti3+ lattice and surface defects. B-doping enhances the formation of Ti4+–O− oxygen vacancies and the quantities of O2H and OH radicals. In B-doped and B–N co-doped samples, boron causes the most prominent induction of Ti3+ lattice centers. Boron in interstitial sites, with oxygen atoms [BO3] behaves as a three-electron donor leading to the formation of B3+ and reduction of Ti4+ to Ti3+. Under UV–vis irradiation, Cr(VI) reduction followed the trend: TB1>TBN1>TBNF1>TNF1>TN1>undoped TiO2; while benzoic acid (BA) oxidation trend was: TB1>TBNF1>TBN1>TNF1>TN1>undoped TiO2. Cr(VI) reduction and BA oxidation rates are in agreement with EPR-detected Ti4+–O− oxygen vacancies and O2H, OH photoexcited radicals, respectively.

Synthesis of C–N–Y tri-doped TiO2 photo-catalyst for MO degradation and characterization

In this research C–N–Y tri-doped TiO2 nanopowders were synthesized by the sol–gel method. The C–N–Y TiO2 photo-catalyst was prepared using hexamine and yttrium nitrate Hexahydrate as the dopant precursors. Methyl-orange (MO) was used to study the photocatalytic performance of the doped TiO2 under UV irradiation. The synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, Transmission electron microscopy, Photoluminescence and Field emission scanning electron microscopy. The tri-doped sample with 8% N, 0.4% Y and 1.5% C exhibited enhanced photocatalytic efficiencies. After 100 min of irradiation with UV light, 87% of MO was decomposed by C–N–Y tri-doped TiO2 sample. It is suggested that the co-activity of C and N could make the intra-gap localized states above the valence band of TiO2, and carbon in TiO2 structure causes carbonate species to appear. These carbonate species acted as photosensitizer on the TiO2 surface to promote photo-catalytic activity of the as synthesized sample.

Shock-Induced C-N-S Tridoped TiO2 with Improved Photocatalytic Activity Under Visible Light

Using metatitanic acid (H2TiO3) and thiourea (CN2H4S) as titanium precursor and dopant sourcerespectively, a visible-light responsiblenon-metalC-N-S tridoped TiO2 photocatalyst is prepared by shock loading. X-ray powderdiffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-visiblediffusereflectancespectroscopy (UV-Vis DRS)are employed to characterize thecrystalline structure,morphology,chemical composition and optical property of recovered samples.The results indicate the metatitanic acid transformsto pure anatase phase by shock wave and that theaverage size of particles is3-5 nm.The as-synthesized TiO2 nano-particles are well dispersedand possess large surface area (309.02m2/g), and the edge adsorptionwavelength of the samples exhibitsslight red shifts with corresponding energy gap reduced to 3.16 eV.Carbon forms carbonate on the surface of TiO2,N may coexist inthe forms of substituted N (N-O-Ti) and interstitial N (O-Ti-N) in TiO2, and S6+is incorporated into the lattice of TiO2through substituting titanium atoms.The photocatalyticactivities of the as-synthesized samples are evaluated for the degradation of Rhodamine B under simulatedsunlight irradiation.Results revealthat these C-N-StridopedTiO2exhibit higherphotocatalyticdegradation activities than that of undoped TiO2samples and achieve an 83% removal rate for RB dye under the visible light irradiation for 70min with the thiourea-to-metatitanic acid mass of 2:1 and flyervelocity 2.52 km·s-1,whichis mainly attributed to the synergistic effects of well-formed anatase phase, high specific surface area and band gap narrowing resulting from C-N-S tridoping.

Study on P, N, and Mo Tri-Doped TiO2--Preparation and Photocatalytic Activities Under Visible Light.

Phosphorous (P), nitrogen (N), and molybdenum (Mo) tri-doped titanium dioxide ((P, N, Mo)-TiO2) were fabricated by hydrothermal method with titanyl sulfate (TiOSO4) and ammonium phosphomolybdate ((NH4)3H4[P4(Mo207)6]) as precursors. (P, N, Mo)-TiO2 was characterized by XRD, Raman, XPS and other advanced analysis devices. And the photocatalytic activites of (P, N, Mo)-TiO2 were evaluated using methylene blue (MB) and sulfosalicylic acid (SSA). Improved visible light response and photocatalytic properties were observed. The mechanism of photodegradation of MB and SSA under visible light by (P, N, Mo)-TiO2 was also proposed.

Microwave-assisted hydrothermal synthesis of Nd, N, and P tri-doped TiO2 from TiCl4 hydrolysis and synergetic mechanism for enhanced photoactivity under simulated sunlight irradiation

A novel high-performance Nd, N, and P tri-doped anatase-TiO2 (NdNPTO) nano-photocatalyst was obtained from TiCl4 hydrolysis by a rapid and energy-saving microwave-assisted hydrothermal method. The effects of Nd, N, or/and P doping on the structural, electronic and optical properties of TiO2 were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption–desorption isotherm, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, electron paramagnetic resonance, UV–vis absorbance spectroscopy, and photoelectrochemical measurements. NdNPTO exhibited excellent photoactivity for the degradation of 4-chlorophenol (4-CP) under simulated sunlight irradiation, which was much superior to commercial P25 TiO2. Scavenging experiments reveal that •OH in the solution was main reactive species, and photogenerated electrons also played a minor role by finally transformed •OH. Synergetic mechanism for the enhanced photoactivity of NdNPTO was discussed in detail. It presented good photocatalytic stability towards degradation of 4-CP under simulated sunlight irradiation, and was suitable to wide application for environment remediation.

Synthesis, characterization and photocatalytic performance of W, N, S-tri-doped TiO2 under visible light irradiation

W–S–N-tri-doped TiO 2 photocatalysts (WSNTiO 2 ) were prepared by a simple sol–gel method. Tungstic acid, sodium sulfate and urea were used as tungsten, sulfur and nitrogen sources, respectively. The morphology and microstructure characteristics of the photocatalysts were evidenced by means of XRD, BET, TEM, SEM and UV–vis DRS techniques. The XRD results show that the main crystal phase of samples is anatase. It was also found that the tri-doping of TiO 2 increases its BET specific surface area from 95 to 121 m 2 ·g −1 . Besides, it was shown that tri-doping narrows the band gap of TiO 2 effectively, which has greatly improved the photocatalytic activity in the visible light region. The photocatalytic activity of tri-doped TiO 2 powders was compared to that of bi-doped ones through the degradation of Congo Red (CR) under visible irradiation. Thus, the prepared 0.5% W–N–S–TiO 2 heat treated at 450 °C showed the best photocatalytic activity compared to the prepared pure TiO 2 , Degussa P25, and co-doped samples (WNTiO 2 and WSTiO 2 ). In particular, a Congo Red degradation rate of approximately 99% was reached after only 35 min of visible light irradiation in the presence of 0.5% of WNSTiO 2 . Total organic carbon (TOC) removal of CR was up to 72% and confirmed its significant mineralization in the presence of 0.5% of WNSTiO 2 photocatalyst.

A facile one-step electrochemical strategy of doping iron, nitrogen, and fluorine into titania nanotube arrays with enhanced visible light photoactivity

Highly ordered iron, nitrogen, and fluorine tri-doped TiO2 (Fe, (N, F)-TiO2) nanotube arrays were successfully synthesized by a facile one-step electrochemical method in an NH4F electrolyte containing Fe ions. The morphology, structure, composition, and photoelectrochemical property of the as-prepared nanotube arrays were characterized by various methods. The photoactivities of the samples were evaluated by the degradation of phenol in an aqueous solution under visible light. Tri-doped TiO2 showed higher photoactivities than undoped TiO2 under visible light. The optimum Fe3+ doping amount at 0.005M exhibited the highest photoactivity and exceeded that of undoped TiO2 by a factor of 20 times under visible light. The formation of N 2p level near the valence band (VB) contributed to visible light absorption. Doping fluorine and appropriate Fe3+ ions reduced the photogenerated electrons–holes recombination rate and enhanced visible light photoactivity. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) results indicated the presence of synergistic effects in Fe, N, and F tri-doped TiO2, which enhanced visible light photoactivity. The Fe, (N, F)-TiO2 photocatalyst exhibited high stability.

Enhanced photocatalytic activity of TiO2 assisted by Nb, N and S multidopants

A novel visible light active photocatalyst is synthesized by doping TiO2 with multiple dopants like Nb, N and S. TiO2 exists as anatase phase and the particle size is in the range of 10–25nm. A significant red shift of the absorption edge and increased visible light absorption is shown by multidoped TiO2 compared to undoped TiO2. The tri-doped TiO2 has the highest activity for the photodegradation of methyl orange and the activity shows the order: 0.6NbNS–TiO2>P25>0.6Nb–TiO2>NS–TiO2>pristine TiO2. The enhanced photocatalytic activity of tri-doped TiO2 is due to the reduction of band gap and enhancement of lifetime of photogenerated charge carriers. This multidoped catalyst is found to be stable and only a marginal decrease in the activity is observed upto 3 cycles. Experiments with quenchers suggest that all super oxide, hydroxyl radicals and photogenerated holes are active species for the oxidation reaction.

Enhanced near-infrared to visible upconversion nanoparticles of Ho³⁺-Yb³⁺-F⁻ tri-doped TiO₂ and its application in dye-sensitized solar cells with 37% improvement in power conversion efficiency.

New near-infrared (NIR)-to-green upconversion nanoparticles of Ho(3+)-Yb(3+)-F(-) tridoped TiO2 (UC-F-TiO2) were designed and fabricated via the hydrosol-hydrothermal method. Under 980 nm NIR excitation, UC-F-TiO2 emit strong green upconversion fluorescence with three emission bands at 543, 644, and 751 nm and convert the NIR light in situ to the dye-sensitive visible light that could effectively reduce the distance between upconversion materials and sensitizers; thus, they minimize the loss of the converted light. Our results show that this UC-F-TiO2 offers excellent opportunities for the other types of solar cells applications, such as organic solar cells, c-Si solar cells, multijunction solar cells, and so on. When integrating the UC-F-TiO2 into dye-sensitized solar cells (DSSCs), superior total energy conversion efficiency was achieved. Under AM1.5G light, open-circuit voltage reached 0.77 ± 0.01 V, short-circuit current density reached 21.00 ± 0.69 mA cm(-2), which resulted in an impressive overall energy conversion efficiency of 9.91 ± 0.30%, a 37% enhancement compared to DSSCs with pristine TiO2 photoanode.

Pr, N, and P tri-doped anatase TiO2 nanosheets with enhanced photocatalytic activity under sunlight

Pr, N, and P tri-doped anatase TiO2 nanosheets (PrNPTO) were synthesized by a combined sol-gel solvothermal method and characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, X-ray photoelectron spectroscopy, UV-vis absorbance spectroscopy, and photoluminescence spectroscopy. When the Pr-doping concentration was 1.75 wt% and calcination temperature employed was 550 °C, the resulting PrNPTO showed the highest photoactivity towards the degradation of methylene blue under visible and UV light irradiation. PrNPTO also displayed superior photoactivity towards the degradation of 4-chlorophenol under sunlight (kapp = 3.90 × 10−2 min−1) over the non-doped, single-doped, and co-doped samples, and P25 TiO2 (kapp = 1.17 × 10−2 min−1). The high photoactivity of PrNPTO was attributed to the increased UV and visible light absorption properties, reduced recombination of photogenerated carriers, increased surface hydroxyl content, and improved surface textural properties. PrNPTO was highly efficient and stable under simulated sunlight irradiation, which are essential attributes for practical application in environment-related remediation schemes.