Steady-state Surface Photovoltage Research Articles

Anchoring AuCu alloy nanoparticles on TiO2 nanosheets: Exploiting synergistic effects and directed electron transfer for enhanced photocatalytic H2 evolution

AuCu/TiO2 composite photocatalysts were prepared by anchoring AuCu nanoparticles (NPs) on TiO2 nanosheets using a simple photoreduction method. Visible diffuse reflectance spectra indicated that the AuCu/TiO2 significantly enhanced light absorption in the visible region. Through photoluminescence spectroscopy and steady-state surface photovoltage experiments, AuCu/TiO2 exhibits an excellent photogenerated electron transfer rate. In addition, photoelectrochemical experiments showed that AuCu/TiO2 had a high photogenerated charge separation efficiency. AuCu/TiO2 (1.0 wt%) exhibited the best performance, under full spectrum, the hydrogen evolution rate is 33.94 mmol g−1 h−1, which is 1.59 times and 1.66 times higher than that of single metal Au/TiO2 (1.0 wt%) (21.28 mmol g−1 h−1) and Cu/TiO2 (1.0 wt%) (20.42 mmol g−1 h−1), respectively. The results showed that AuCu NPs greatly enhanced the photocatalytic performance of the composite photocatalysts.

AuPt bimetallic loaded defect state g-C3N4 enhances photocatalytic H2 evolution: Exploring synergistic effects and charge transfer mechanisms

AuPt alloy nanoparticles (NPs) were prepared using a simple photodeposition method to modify defective state g-C3N4 nanosheets (HCN) which contained N vacancies, B doping, and CN groups. The visible diffuse reflectance spectra (DRS) indicate that AuPt/HCN exhibits high light absorption capability. The photoluminescence spectrum (PL) and steady-state surface photovoltage (SPV) indicate that AuPt/HCN possesses a high rate of photogenerated charge separation and a high efficiency of photogenerated electron transfer. The electrochemical tests indicate that AuPt/HCN exhibits lower electrochemical impedance. AuPt/HCN (1.0 wt%) exhibits outstanding photocatalytic hydrogen evolution efficiency, producing hydrogen at a rate of 2095 μmol·g−1·h−1 under visible light, which is 2.10 times and 1.55 times higher than that of monometallic Au/HCN (1.0 wt%) (997 μmol·g−1·h−1) and Pt/HCN (1.0 wt%) (1349 μmol·g−1·h−1), respectively. The bimetallic synergistic effect of AuPt alloy NPs co-catalysts enhances the photocatalytic hydrogen evolution activity of AuPt/HCN composite photocatalysts.

Effective nitrogen doping of TiO2 polymorphs at mild temperatures for visible-light-responsive hydrogen evolution

Herein, a mild-temperature nitrogen doping route with the urea-derived gaseous species as the active doping agent is proposed to realize visible-light-responsive photocatalytic hydrogen evolution both for the anatase and rutile TiO2. DFT simulations reveal that the cyanic acid (HOCN), derived from the decomposition of urea, plays a curial role in the effective doping of nitrogen in TiO2 at mild temperatures. Photocatalytic performance demonstrates that both the anatase and rutile TiO2 doped at mild temperatures exhibit the highest hydrogen evolution rates, although the ones prepared at high temperatures possess higher absorbance in the visible range. Steady-state and transient surface photovoltage characterizations of these doped TiO2 polymorphs prepared at different temperatures reveal that harsh conditions (high temperature reaction) typically result in the formation of intrinsic defects that are detrimental to the transport of the low-energy visible-light-induced electrons, while the mild-temperature nitrogen-doping could flatten the pristine upward band bending without triggering the formation of Ti3+, thus achieving enhanced visible-light-responsive hydrogen evolution rates. We anticipate that our findings will provide inspiring information for shrinking the gap between the visible-light-absorbance and the visible-light-responsiveness in the band engineering of wide-bandgap metal-oxide photocatalysts.

Improved visible-light activities of ultrathin CoPc/g-C3N4 heterojunctions by N-doped graphene modulation for selective benzyl alcohol oxidation

The interface modulation is the key factor affecting the photoactivity of metal phthalocyanine (MPc)/g-C3N4 heterojunctions for aerobic selective alcohol oxidation. Here, we have successfully fabricated the N-doped graphene-modulated CoPc/g-C3N4 nanosheets (CoPc/NG/CN) heterojunctions. Optimal CoPc/NG/CN photocatalyst demonstrates approximately fourfold photoactivity improvement for benzyl alcohol oxidation with ∼99% selectivity toward benzyl aldehyde and of approximately ninefold 2,4-dichlorophenol degradation rate compared with bare CN, using O2 as oxidant. By means of steady-state surface photovoltage responses in N2 atmosphere, time-resolved photoluminescence spectra, single-wavelength photocurrent action spectra, and electrochemical O2 reduction measurements, it is confirmed that the exceptional photoactivities of resulting CoPc/NG/CN heterojunction are attributed to the facilitated interfacial charge transfer between CoPc and CN by the modulation of NG with favorable electron-induced capacity. In addition, more enriched hydroxyl groups of NG by N doping could induce high dispersion of CoPc molecules via H-bonding effect, resulting in the increase of exposed number of CoPc as visible-light absorption units and single Co2+ sites as catalytic centers for O2 activation so as to further benefit the photocatalytic oxidation processes. This work provides a feasible interfacial modulation strategy to fabricate efficient supported MPc-based heterojunction photocatalyst nanomaterials.

Effect of Calcination Temperature on the Photocatalytic H2 Evolution of Bronze Phase Monoclinic TiO2(B) Nanosheets

In this work, we have successfully fabricated bronze phase monoclinic TiO2 (B) nanosheets from TiCl3 under hydrothermal conditions. The fabricated samples were calcined at different annealing temperature (100, 200, 300, 400 and 500 oC) to select optimum temperature under UV light irradiation for the efficient photocatalytic water splitting. Different techniques were used for the characterization of fabricated photocatalysts. Interestingly, the sample calcined at 400 oC delivered optimum H2 evolution from water which is attributed to the relatively high surface area and effective charge separation. The characteristic anisotropic nature of TiO2(B) plays very crucial role in charge separation which is evident from photoluminescence spectra, steady-state surface photovoltage spectra, and produced hydroxyl radical amount. It has been concluded that optimum annealing temperature generally introduces charge trapping centres which help in the separation of excite charges for improved photocatalytic activity. However, high temperature results in particles aggregation to reduce the surface area and hence retards the photocatalytic efficiency. This work will direct future research to fabricate materials at optimized temperature for the improved photocatalytic activities.

One‐step hydrothermal synthesis of ZnO microtubes with an efficient photocatalytic activity

In this work, the novel rod-like ZnO microtubes were successfully synthesized via one-step simple, non-toxic, fast and economical hydrothermal route. The as-obtained microtubes were characterized in detail with X-ray diffraction, scanning electron microscope, UV–visible diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, steady-state photoluminescence spectrum and surface photovoltage spectroscopy. The photocatalytic activity of the as-obtained microtubes was evaluated by degradation of methylene blue. The results indicated that the ZnO microtubes, exhibited higher photodegradation efficiency of 95% under UV light irradiation (λ ≤ 420 nm) for 20 min. The photodegradation could be described as the pseudo-first-order kinetics with apparent rate constant of 0.126 min-1, which was based on the unique morphology of ZnO. Moreover, ZnO microtubes maintained a good photostability after three consecutive cycles. Unique microtubes can be applied practically for dye waste-water treatment.

Atomic force microscopy: Emerging illuminated and operando techniques for solar fuel research.

Integrated photoelectrochemical devices rely on the synergy between components to efficiently generate sustainable fuels from sunlight. The micro- and/or nanoscale characteristics of the components and their interfaces often control critical processes of the device, such as charge-carrier generation, electron and ion transport, surface potentials, and electrocatalysis. Understanding the spatial properties and structure-property relationships of these components can provide insight into designing scalable and efficient solar fuel components and systems. These processes can be probed ex situ or in situ with nanometer-scale spatial resolution using emerging scanning-probe techniques based on atomic force microscopy (AFM). In this Perspective, we summarize recent developments of AFM-based techniques relevant to solar fuel research. We review recent progress in AFM for (1) steady-state and dynamic light-induced surface photovoltage measurements; (2) nanoelectrical conductive measurements to resolve charge-carrier heterogeneity and junction energetics; (3) operando investigations of morphological changes, as well as surface electrochemical potentials, currents, and photovoltages in liquids. Opportunities for research include: (1) control of ambient conditions for performing AFM measurements; (2) in situ visualization of corrosion and morphological evolution of electrodes; (3) operando AFM techniques to allow nanoscale mapping of local catalytic activities and photo-induced currents and potentials.

In-situ generation of g-C3N4 on BiVO4 photoanode for highly efficient photoelectrochemical water oxidation

Constructing a heterojunction photoelectrode is an effective way to promote the photogenerated charge separation in photoelectrochemical (PEC) water oxidation. In this work, we successfully fabricated C3N4/BiVO4 hybrid electrodes by integrating g-C3N4 onto the nanoporous BiVO4 via a simple in-situ synthesis method. The as-prepared C3N4/BiVO4 photoanodes were systematically studied by Electrochemical Impedance Spectroscopy, steady-state surface photovoltage (SPV), transient SPV, Open circuit potential and Photoluminescence measurements. With an optimal loading of g-C3N4, the 2-C3N4/BiVO4 electrode showed a high photocurrent density of 4.06 mA/cm2 at 1.23 V (vs. RHE) for water oxidation, a 2.8 times enhancement over that of the BiVO4. It is found that g-C3N4 improved the PEC performance of the photoanodes by simultaneously promoting the charge separation and surface reaction kinetics. When a NiOOH co-catalyst was immobilized onto the 2-C3N4/BiVO4 electrode, both the PEC property and stability of the photoanode were enhanced. An extremely high photocurrent density of 5.44 mA/cm2 at 1.23 V was achieved. The largest half-cell solar energy conversion efficiency for NiOOH/2-C3N4/BiVO4 was 1.43% at 0.78 V, corresponding to 8.4 times that of unmodified BiVO4 (0.17% at 0.97 V). This work brings new insight into the development of C3N4-based devices for application in solar to fuel conversion.

Plasmonic Ag decorated graphitic carbon nitride sheets with enhanced visible-light response for photocatalytic water disinfection and organic pollutant removal.

Photocatalytic disinfection with high performance is thought to be a promising way for water purification. Herein, plasmonic Ag doped urea-derived graphitic carbon nitride (g-C3N4) composites were fabricated via in-situ photo-deposition at room temperature as the visible-light photocatalyst. Scan electron microscopy and transmission electron microscopy images showed the uniform dispersion of Ag nanoparticles on the surface of g-C3N4 sheet, which facilitated the synergistic effect of antibacterial performance from Ag and photocatalytic property from Ag/g-C3N4 composites. Photocatalytic water disinfection against Escherichia coli with visible light was performed to demonstrate the improved photocatalytic property with assistance of Ag. The 3-Ag/g-C3N4 exhibited the best bactericidal performance by inactivating all bacteria within 120 min with damaged cell membranes of Escherichia coli observed by scan electron microscopy and transmission electron microscopy images. Photoluminescence spectra, steady-state surface photovoltage spectra, photocurrent response, and electrochemical impedance spectra results revealed that Ag nanoparticles inhibited the recombination of photo-generated e- and h+ pairs and further reinforced the photocatalytic performance of g-C3N4. Scavenger experiments indicated that h+ produced on valence band of g-C3N4 dominated the photocatalytic disinfection process against Escherichia coli. This work further proved Ag/g-C3N4 showed great potential in photocatalytic water disinfection under visible-light irradiation.

Promoted oxygen activation of layered micro-mesoporous structured titanium phosphate nanoplates by coupling nano-sized δ-MnO2 with surface pits for efficient photocatalytic oxidation of CO

It is highly desired to fabricate efficient micro-mesoporous structured photocatalysts with strong oxygen activation ability for CO oxidation. Herein, a layered micro-mesoporous structured titanium phosphate (L-MMS-TiP) with high photocatalytic activity for CO oxidation has been successfully synthesized by a two-step solvothermal method. The photocatalytic activity of resulting L-MMS-TiP could be greatly improved by coupling a proper amount of nano-sized δ-MnO2, especially for that with surface pits. The improved activities are mainly attributed to the roles of coupled δ-MnO2 in enhancing photogenerated charge separation and promoting oxygen activation, which is revealed based on measurements of the steady-state surface photovoltage spectra, nitroblue tetrazolium absorption spectra, electron paramagnetic resonance spectra and in situ DRIFTS spectra. Interestingly, the photocatalytic activity of pitted δ-MnO2-coupled L-MMS-TiP is superior to that of P25 TiO2, even much higher than that of Au-coupled L-MMS-TiP. Significantly, δ-MnO2-coupled L-MMS-TiP also has excellent oxidation removal effect for other harmful or even mixed gases. Moreover, it is confirmed that δ-MnO2 with the two-dimensional structure is the best one to couple L-MMS-TiP for photocatalytic CO oxidation among all four kinds of crystal phases and compared with other transitional metal oxides. This work opens up a new way to develop a layered micro-mesoporous structure-based nanocomposite, and further improve the photocatalytic activity by promoting oxygen activation with two-dimensional pitted δ-MnO2.

Probing Defect States in Organic Polymers and Bulk Heterojunctions Using Surface Photovoltage Spectroscopy

We performed frequency-modulated (AC) and steady-state (DC) surface photovoltage spectroscopy (SPS) measurements on a bilayer structure consisting of an organic semiconductor (P3HT, P3HT:PC61BM, or...

Synthesis of Au-decorated three-phase-mixed TiO2/phosphate modified active carbon nanocomposites as easily-recycled efficient photocatalysts for degrading high-concentration 2,4-DCP.

It is of great significance to fabricate easily-recycled TiO2 photocatalysts with high activity. Herein, dominant-anatase three-phase (anatase/rutile/brookite)-mixed nanosized TiO2 with high photocatalytic activity for degrading a high-concentration of 2,4-DCP has been synthesized via a hydrothermal process with HCl as a phase-directing agent, and interestingly the apparent photoactivity could be greatly improved by decorating Au nanoparticles and then coupling phosphate-treated active carbon. The amount-optimized nanocomposite displays ∼12-fold enhancement in degradation rate constant (k) compared to anatase TiO2. Based on the steady-state surface photovoltage spectra, fluorescence spectra related to the produced ·OH amount, temperature-programmed desorption and O2 electrochemical reduction curves, it is confirmed that the exceptional photoactivity is mainly attributed to the greatly-enhanced charge separation from the phase-mixed composition, and from the decorated Au as electron acceptors and its promotion effects on O2 activation. Moreover, the use of phosphate-modified AC as a support is also positive for efficient photocatalytic reactions by accepting electrons and concentrating the pollutants, with recyclable features. This work provides a feasible strategy to fabricate TiO2-based nano-photocatalysts for degrading high-concentration pollutants to remediate the environment.

Numerical simulation and validity of the surface photovoltage method in amorphous silicon with a Schottky contact

The steady-state surface photovoltage technique (SPV) is widely used to evaluate minority photocarriers diffusion length for the characterization of photovoltaic device performance. This contact technique shows the difficulty to evaluate the true minority photocarriers diffusion length (Lp) of hydrogenated amorphous silicon (a-Si:H) even though the space charge region is reduced. In this work, we propose a formula to predict more accurately minority diffusion length Lp depending on apparent diffusion length (Lapp) and space charge width (W). This formula is deduced by Moore’s analytical solution in relation to other forms. All transport phenomena taken into account, a complete one-dimensional numerical simulation of the SPV on an Au/a-Si:H Schottky structure is developed. The apparent diffusion length Lapp and the space charge width W are determined using SPV simulation. The standard density of states (DOS) of the a-Si:H is used. Poisson’s equation and the two continuity equations for charge carriers are numerically solved. The SPV assumptions involving W are explored for a set of parameters of the a-Si:H DOS. This numerical simulation shows a linear dependence of Lapp up on the valence band tail energy, which agrees well with the experimental results. The Lp values obtained by the new formula are compared to Lapp and discussed for a typical DOS parameters of a-Si:H.

Improved photoelectric properties of BiOBr nanoplates by co-modifying SnO2 and Ag to promote photoelectrons trapped by adsorbed O2

It is highly desired to improve the photoelectric property of nanosized BiOBr by promoting the photogenerated charge transfer and separation. Herein, SnO2 and Ag comodified BiOBr nanocomposites (Ag-SO-BOB) have been prepared through a simple one-pot hydrothermal method. Surface photovoltage response of BiOBr nanoplates has 4.1- time enhancement after being modified with SnO2 nanoparticles. Transient-state surface photovoltage (TS-SPV) and the atmosphere-controlled steady-state surface photovoltage spectroscopy (AC-SPS) confirmed that this exceptional enhancement of the photovoltage response can be ascribed to the coupled SnO2 acting as platform for accepting the photoelectrons from BiOBr so as to prolong the lifetime and enhance charge separation. Remarkably, the surface photovoltage response can be further enhanced by synchronously introducing Ag nanoparticles, which is up to 15.4-times enhancement compared with bulk BiOBr nanoplates. The enhancement can be attributed to the improved O2 adsorption by introducing Ag to further enhance charge separation. Finally, the synergistic effect of SnO2 and Ag co-modification enhances the surface photovoltage response due to the enhanced charge separation and promoted O2 adsorption, which is also confirmed through photoelectrochemistry and photocatalytic experiment.

Improved visible-light photoactivity of Pt/g-C3N4 nanosheets for solar fuel production via pretreated boric acid modification

In this work, the photocatalytic activities of g-C3N4 nanosheets for CO2 conversion and H2 production were obviously promoted by modifying an appropriate amount of Pt as the photoelectron-acceptor and co-catalyst. The optimized 0.5Pt–CN displayed ~ 2-times higher photocatalytic activities for both CO2 reduction and H2 production than those of bare CN nanosheets. Importantly, the photocatalytic activities for solar fuel production of Pt–g-C3N4 nanosheets can be further enhanced by pretreating a suitable amount of boric acid modification on g-C3N4 nanosheets. Compared to 0.5Pt–CN and bare CN, the optimized 0.5Pt–5B–CN (5% boric acid in molar ratios) displayed ~ 2- and 9-times enhancement for reducing CO2 to CO, as well as CH4 while ~ 2- and 10-times enhancement for H2 production, respectively. By means of the steady-state surface photovoltage spectra, fluorescence spectra and fluorescence spectra related to the produced ·OH amount, the exceptional photoactivities were comprehensively attributed to the boric acid-assisted high dispersion of Pt on g-C3N4 nanosheet which enhances the charge separation and improves the co-catalytic activity. This pretreated boric acid modification strategy is also applicable for other noble metals like Ag and Au. This work provides a new strategy on developing an efficient g-C3N4-based photocatalyst for solar fuel production.

Enhanced Charge Separation of TiO2 Nanotubes Photoelectrode for Efficient Conversion of CO2

For the production of TiO2 nanotubes (TNTs) efficient photoelectrodes they must have efficient charge separation by trapping holes and transfer of electrons. In this study, MnOx and Pd codecorated TNTs photoelectrodes were successfully constructed using a simple impregnation method, followed by an electrochemical deposition process. The photocatalytic activities for CO2 conversion by the optimized TNTs photoelectrode (10Pd/0.8Mn/TNTs) were increased by 2.8 times to produce 40.3 ± 2.5 mg L–1 acetic acid, and by 2.5 times to generate 24.6 ± 1.9 mg L–1 formic acid compared to a bare TNTs photoelectrode. The optimized photoelectrode also showed the highest transient photocurrent of 1.15 mA cm–2. The improved performance was due to the elevated charge separation through bidirectional modulation of photogenerated holes and electrons, on the basis of the steady-state surface photovoltage and analysis with the formed •OH concentrations, electrochemical reduction tests with N2 or CO2 atmospheres, and electrochemical impedance spectra. The decorated MnOx effectively trapped the photogenerated holes, and the decorated Pd facilitated photogenerated electron transfer and promoted visible light absorption. The decorated MnOx and Pd also played catalytic roles in the redox reactions involved with the photogenerated charge carriers.

Localization and Stabilization of Photogenerated Electrons at TiO2 Nanoparticle Surface by Oxygen at Ambient Temperature.

Understanding the mechanism by which oxygen adsorption influences the separation behavior of charge carriers is important in photocatalytic removal of air pollutants. In this study, we performed steady-state surface photovoltage and surface photocurrent spectroscopy combined with an atmosphere control system to determine the effect of oxygen on the charge separation behavior at the surface of anatase TiO2 nanoparticles at ambient temperature. Results showed that photogenerated electrons were movable in N2 atmosphere but were localized in O2 atmosphere. O2 obviously enhanced the stabilization of the localized photogenerated electrons when the surface defects of TiO2 were fully occupied by adsorbed O2. Moreover, O2 adsorption increased the energy demand for exciting electrons from the valence band to localized surface defect states and reduced the density of band tail states. These findings suggest us that the effect of gaseous species on the mobility and stability of charge carriers should be considered to understand the photocatalytic degradation of air pollutants.

Visible-light induced electron modulation to improve photoactivities of coral-like Bi2WO6 by coupling SnO2 as a proper energy platform

It is essential to improve the activity of Bi2WO6 for the photocatalytic 2,4-dichlorophenol (2,4-DCP) degradation by modulating the visible-light excited photogenerated electrons. As for this, Bi2WO6 nanostructures have been synthesized by a mannitol assistant hydrothermal method. It is shown that the temperature-optimized Bi2WO6 exhibits high photocatalytic activity for 2,4-DCP degradation under visible-light irradiation, attributed to the coral-like structure, high crystallinity and large surface area. Interestingly, the photocatalytic activities of coral-like Bi2WO6 could be further improved by coupling ultrafine nanocrystalline SnO2. It is confirmed mainly from the steady-state and transient-state surface photovoltage responses and fluorescence spectra related to the formed hydroxyl radical amounts that the coupled SnO2 is taken as a proper energy platform to accept the visible-light excited high-energy-level photogenerated electrons from Bi2WO6, consequently enhancing the charge separation and prolonging the charge lifetime. Moreover, the optimized SnO2-coupled BWO exhibits higher photocatalytic activity under UV–vis light irradiation than the commercial P25 TiO2. This work will provide a new feasible route to prepare highly efficient Bi2WO6-based photocatalysts for purifying chlorophenol-polluted water environments.

Synthesis of ZnO/Bi-doped porous LaFeO3 nanocomposites as highly efficient nano-photocatalysts dependent on the enhanced utilization of visible-light-excited electrons

ZnO coupled Bi-doped porous LaFeO3 nanocomposites have successfully been fabricated via a wet-chemical method. It is confirmed that Bi3+ enters into the crystal lattice of PLFO and substitute La3+, while the ZnO with diameter of ∼15 nm is coupled to the Bi-doped PLFO. It is shown that the amount-optimized 5Zn/7Bi-PLFO nanocomposite exhibits greatly improved visible-light activities for 2,4-dichlorophenol (2,4-DCP) degradation and CO2 conversion, compared to the unmodified PLFO with rather high photoactivity due to its large specific surface area. Based on the measurements of valence band XPS spectra, steady-state surface photovoltage spectra, transient-state surface photovoltage responses, photoelectrochemical I–V curves, fluorescence spectra related to produced OH amount and photocurrent action spectra, it is clearly demonstrated that the significantly improved visible-light activities are attributed to the enhanced utilization of visible-light-excited high-level-energy electrons (HLEEs) by coupling with nanocrystalline ZnO to introduce a new energy platform for accepting electrons and to the extended visible-light absorption by doping Bi3+ to create surface states. Interestingly, it is proved that under UV–vis irradiation, the amount-optimized nanocomposite exhibit much higher photoactivity for 2,4-DCP degradation compared to the commercially available P25 TiO2. Moreover, it is confirmed by means of radical trapping experiments that the dominant radicals to decompose 2,4-DCP on PLFO could be modulated by doping Bi3+ and coupling ZnO. Furthermore, the possible decomposition pathways, respectively related to the OH and O2−, of 2,4-DCP over the amount-optimized Bi-doped PLFO and ZnO coupled Bi-doped PLFO samples are proposed by means of the liquid chromatography tandem mass spectrometry analysis of the intermediates, especially with the used isotopic D2O.

Synthesis of nano SnO2-coupled mesoporous molecular sieve titanium phosphate as a recyclable photocatalyst for efficient decomposition of 2,4-dichlorophenol

It is essential to develop a cheap, recyclable, and efficient photocatalyst to help degrade pollutants contaminating the environment. Herein, mesoporous molecular sieve titanium phosphate (MMS-TiP) was used as an efficient nano-photocatalyst to degrade 2,4-dichlorophenol (2,4-DCP) and to oxidize CO. The catalyst was successfully synthesized by a simple and convenient hydrothermal method in the presence of a tri-block copolymer surfactant. Exceptional photoactivity of the optimized MMS-TiP mainly depends on its porous structure, with a large surface area by means of O2 temperature-programmed desorption curves and fluorescence spectra related to the amounts of produced hydroxyl radical. Interestingly, the photocatalytic activity of the prepared MMS-TiP could be greatly improved by coupling with nanocrystalline SnO2. This is likely due to the increase in the lifetime and separation of photogenerated charges by transferring electrons to SnO2 and was observed by steady-state surface photovoltage spectra and time-resolved surface photovoltage responses. The SnO2-coupled MMS-TiP exhibits better photocatalytic performance for 2,4-DCP degradation and better self-settlement than those of the commercial catalyst P25 TiO2. Moreover, it was confirmed by radical-trapping experiments that ·O2–is the main activated species for the photocatalytic degradation of 2,4-DCP, and is photogenerated by electron transfer from MMS-TiP to SnO2. Furthermore, the main intermediates in the degradation of 2,4-DCP, like parachlorophenol superoxide and 1,2-benzenediol superoxide radicals, were detected, and a possible decomposition pathway related to ·O2–attack is proposed. These experimental results provide new strategies for developing a recyclable molecular sievebased nano-photocatalyst with high photocatalytic activity for environmental remediation.