Synthesis and applications of carbon nanomaterials for energy generation and storage

• Marco Notarianni,
• Jinzhang Liu,
• Kristy Vernon and
• Nunzio Motta

Beilstein J. Nanotechnol. 2016, 7, 149–196, doi:10.3762/bjnano.7.17

• 15 and a conductivity of 300 S/cm with HI acid. Derivative approaches of the chemical method have also been employed to reduce GO: photocatalyst reduction where the GO mixed with TiO2 particles is exposed to ultraviolet (UV) irradiation [131]; electrochemical reduction with an inert electrode placed

Impact of ultrasonic dispersion on the photocatalytic activity of titania aggregates

• Hoai Nga Le,
• Frank Babick,
• Klaus Kühn,
• Minh Tan Nguyen,
• Michael Stintz and
• Gianaurelio Cuniberti

Beilstein J. Nanotechnol. 2015, 6, 2423–2430, doi:10.3762/bjnano.6.250

• effectiveness of photocatalytic materials increases with the specific surface area, thus nanoscale photocatalyst particles are preferred. However, such nanomaterials are frequently found in an aggregated state, which may reduce the photocatalytic activity due to internal obscuration and the extended diffusion

• promising photocatalyst because of its commercial availability, chemical and biological inertness, and because it has no known adverse health effects on humans [5][6]. Due to its large active surface area, the suspended TiO2 powder is favored [6]. Most slurry photocatalysts have been implemented in

• experimental setup, which defines the process parameters. In addition, ultrasonic dispersion was used to disintegrate the P25 nano-photocatalyst as well as vary the size. The photocatalytic activity was examined by the discoloration of MB under UV irradiation. Experimental Materials All experiments were

Effect of SiN_x diffusion barrier thickness on the structural properties and photocatalytic activity of TiO₂ films obtained by sol–gel dip coating and reactive magnetron sputtering

• Mohamed Nawfal Ghazzal,
• Eric Aubry,
• Nouari Chaoui and
• Didier Robert

Beilstein J. Nanotechnol. 2015, 6, 2039–2045, doi:10.3762/bjnano.6.207

• presence of an uncoated SLG under UV–vis illumination or in the dark in the presence of the TiO2 photocatalyst. Thus, the OII was not photobleached by photolysis nor was it adsorbed at the surface of the photocatalyst, which suggests a neglected effect of the specific surface area of the film on the

• the adsorption/bleaching of the azo molecule [18]. This means that even the dye molecule OII could absorb visible light to produce the excited singlet and/or triplet state of the OII molecule [19], the OII may be able to sensitize the TiO2 photocatalyst. However, the degradation of the OII dye via the

• increasing the SiNx diffusion barrier thickness affects the interfacial electron transfer rate [20]. The photo-generated electron–hole pair produced in the bulk of the photocatalyst during the illumination diffuses faster to reach the surface, since the distance traveled is reduced by the smaller crystallite

High photocatalytic activity of V-doped SrTiO₃ porous nanofibers produced from a combined electrospinning and thermal diffusion process

• Panpan Jing,
• Wei Lan,
• Qing Su and
• Erqing Xie

Beilstein J. Nanotechnol. 2015, 6, 1281–1286, doi:10.3762/bjnano.6.132

• /bjnano.6.132 Abstract In this letter, we report a novel V-doped SrTiO3 photocatalyst synthesized via electrospinning followed by a thermal diffusion process at low temperature. The morphological and crystalline structural investigations reveal not only that the V-doped SrTiO3 photocatalyst possesses a

• photocatalytic activity with excellent endurance. Results and Discussion The morphology and microstructure are very important for the development of an excellent photocatalyst. In Figure 1a, the pure SrTiO3 nanofibers appear to be tens of micrometers in length, with a porous surface and uniform diameter

• distribution. The pore size and diameter distributions were measured to be about 10–32 nm and 90–240 nm, respectively. Such a long fibrous and porous structure is beneficial to electron transfer, dye molecular absorption and the light utilization efficiency for a photocatalyst. In Figure 1b, the morphological

Effects of swift heavy ion irradiation on structural, optical and photocatalytic properties of ZnO–CuO nanocomposites prepared by carbothermal evaporation method

• Sini Kuriakose,
• D. K. Avasthi and
• Satyabrata Mohapatra

Beilstein J. Nanotechnol. 2015, 6, 928–937, doi:10.3762/bjnano.6.96

• of CuO. This helps to inhibit the recombination of photogenerated electrons and holes and improves the charge separation efficiency. The oxygen molecules adsorbed on the photocatalyst form superoxide anion radicals (•O2−) due to their interaction with electrons in the conduction band of ZnO. Surface

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

• Desiré M. De los Santos,
• Javier Navas,
• Teresa Aguilar,
• Antonio Sánchez-Coronilla,
• Concha Fernández-Lorenzo,
• Rodrigo Alcántara,
• Jose Carlos Piñero,
• Ginesa Blanco and
• Joaquín Martín-Calleja

Beilstein J. Nanotechnol. 2015, 6, 605–616, doi:10.3762/bjnano.6.62

• semiconductors used as a photocatalyst for the degradation of organic compounds. This is due to its high chemical and biological stability, low cost, excellent electronic and optical properties, and the strong oxidation capacity of its photogenerated holes [1][2]. Photocatalytic activity depends on several

• catalytic properties, such as band gap energy, specific surface area, the extent of crystallinity, the structure of the material, etc. [3]. In general, a good photocatalyst should efficiently absorb photons with an energy equal to or higher than its band gap, thus generating an electron–hole pair. These

• photodegradation of methylene blue (MB) was performed using a set of five actinic lamps emitting at around 360 nm. The initial concentration of the aqueous solution of MB (purity 82%, Panreac) was 1.56 · 10−5 M, and the concentration of the photocatalyst was 0.3 g·L−1. The photocatalyst/MB mixture was kept in

Palladium nanoparticles anchored to anatase TiO₂ for enhanced surface plasmon resonance-stimulated, visible-light-driven photocatalytic activity

• Kah Hon Leong,
• Hong Ye Chu,
• Shaliza Ibrahim and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2015, 6, 428–437, doi:10.3762/bjnano.6.43

• Lumpur, Malaysia 10.3762/bjnano.6.43 Abstract Freely assembled palladium nanoparticles (Pd NPs) on titania (TiO2) nano photocatalysts were successfully synthesized through a photodeposition method using natural sunlight. This synthesized heterogeneous photocatalyst (Pd/TiO2) was characterized through

• ; nano photocatalysts; noble metal; photodeposition; sunlight; Introduction Heterogeneous photocatalysts that employ TiO2 as metal oxide photocatalyst have raised the interest of many researchers since the discovery of the photocatalytic splitting of water under UV light irradiation by Fujishima and

• collective oscillation of conduction electrons that are induced by the incident electromagnetic radiation [9]. Moreover, the formation of Schottky barriers caused by the contact of noble metal NPs with the semiconductor photocatalyst further enhance the separation of electrons and holes, which in turn reduce

Inorganic Janus particles for biomedical applications

• Isabel Schick,
• Steffen Lorenz,
• Dominik Gehrig,
• Stefan Tenzer,
• Wiebke Storck,
• Karl Fischer,
• Dennis Strand,
• Frédéric Laquai and
• Wolfgang Tremel

Beilstein J. Nanotechnol. 2014, 5, 2346–2362, doi:10.3762/bjnano.5.244

• und the excitation of charge carriers within the photocatalyst [48]. Upon conjugation of semiconductor nanoparticles, such as TiO2 to metal nanoparticles, charge equilibration takes place when the composite material is photoexited (Figure 6c). As a direct consequence, the Fermi level of semiconductor

Synthesis of hydrophobic photoluminescent carbon nanodots by using L-tyrosine and citric acid through a thermal oxidation route

• Venkatesh Gude

Beilstein J. Nanotechnol. 2014, 5, 1513–1522, doi:10.3762/bjnano.5.164

• quantum yield of the mixture of CNDs [37]. Another interesting optical property of these tyrosine-passivated CNDs is upconversion photoluminescence (UCPL) when irradiated with wavelengths above 500 nm, which is very important for applications as photocatalyst and for light harvesting applications [2][5

Characterization and photocatalytic study of tantalum oxide nanoparticles prepared by the hydrolysis of tantalum oxo-ethoxide Ta₈(μ₃-O)₂(μ-O)₈(μ-OEt)₆(OEt)₁₄

• Subia Ambreen,
• N D Pandey,
• Peter Mayer and
• Ashutosh Pandey

Beilstein J. Nanotechnol. 2014, 5, 1082–1090, doi:10.3762/bjnano.5.121

• thermal stability of the as-prepared (dried) photocatalyst with α-Al2O3 as the reference. Figure 6 shows the TG/DTA/DSC curves obtained from the dried gel of Ta2O5. The TGA graph shows a weight loss up to a temperature of 200 °C that is essentially attributed to dehydration. The decomposition of organic

• degradation of rhodamine B Figure 12 shows the degradation of dye for different of the catalyst loadings. It is clear that the optimum (89%) degradation of the dye was achieved (after 150 minutes) when 0.8 mg/mL of the photocatalyst was used in the experiment. However, when the used amounts of photocatalyst

• were 0.2 mg/mL, 0.5 mg/mL and 1.1 mg/mL, the degradation of dye occurred up to 55%, 68% and 74%, respectively. The amount of the photocatalyst was changed in each experiment while keeping the other factors invariable to study the optimum degradation of dye with respect to the amount of Ta2O5. By

DFT study of binding and electron transfer from colorless aromatic pollutants to a TiO₂ nanocluster: Application to photocatalytic degradation under visible light irradiation

• Corneliu I. Oprea,
• Petre Panait and
• Mihai A. Gîrţu

Beilstein J. Nanotechnol. 2014, 5, 1016–1030, doi:10.3762/bjnano.5.115

• ; density functional theory; photocatalytic degradation; titanium dioxide; visible light irradiation; Introduction Titania, TiO2, has been widely used as photocatalyst for environmental applications [1][2][3][4][5][6], particularly for waste water purification. Due to its large band gap TiO2 absorbs only

• UV radiation, a fact that limits the efficiency and keeps the costs of the photocatalytic degradation of environmental pollutants high. To be used under visible light irradiation, in the range of wavelengths where the solar spectrum has its maximum, the electronic band structure of the photocatalyst

• has to be modified in various ways [6]. Alternative approaches to the modification of the TiO2 photocatalyst are the self-sensitized degradation of dyes which absorb visible light [7][8] and the photocatalytic degradation of colorless organic compounds by formation of a charge-transfer-complex, CTC [9

Functionalized nanostructures for enhanced photocatalytic performance under solar light

• Liejin Guo,
• Dengwei Jing,
• Maochang Liu,
• Yubin Chen,
• Shaohua Shen,
• Jinwen Shi and
• Kai Zhang

Beilstein J. Nanotechnol. 2014, 5, 994–1004, doi:10.3762/bjnano.5.113

• production under visible light [19]. We have also investigated the visible-light-driven photocatalytic performance over a nanosized WS2-sensitized mesoporous TiO2 photocatalyst [20]. Compared to bulk TiO2 without mesopores, more WS2 can be loaded in the mesoporous TiO2. Moreover, the mesoporous channels can

• efficient hydrogen evolution. Generally, MCM-41 is not photo-reactive. But it can be activated by coupling with a semiconductor or doping a transitional metal. Figure 3 shows the proposed charge separation mechanism within a representative transitional metal-containing molecular sieve photocatalyst [21]. In

• platinum was demonstrated to be more efficient than metallic platinum as cocatalyst for hydrogen production [23][24]. Taking into account the cost of the designed photocatalyst for commercial purposes, the development of noble-metal free cocatalysts is still valued. Alternative cocatalysts such as MoS2

Enhancement of photocatalytic H₂ evolution of eosin Y-sensitized reduced graphene oxide through a simple photoreaction

• Weiying Zhang,
• Yuexiang Li,
• Shaoqin Peng and
• Xiang Cai

Beilstein J. Nanotechnol. 2014, 5, 801–811, doi:10.3762/bjnano.5.92

• characterized by a high activity for H2 evolution under visible light irradiation. Recently, to improve the photocatalytic activity for hydrogen evolution in the visible light region, EY has been employed to sensitize RGO, and the sensitized photocatalyst displays an increased photoactivity for hydrogen

• −2 mol L−1 TMA, pH 10.0; irradiation 2 h. (C) The effect of the RGO24 concentration on the photocatalytic H2 evolution over EY-RGO24/Pt. Conditions: 5.0 × 10−4 mol L−1 EY; 4.6 × 10−6 mol L−1 H2PtCl6; 7.7 × 10−2 mol L−1 TMA, pH 10.0; irradiation 2 h. AQY of the EY-RGO24/Pt photocatalyst plotted as a

Antimicrobial properties of CuO nanorods and multi-armed nanoparticles against B. anthracis vegetative cells and endospores

• Pratibha Pandey,
• Merwyn S. Packiyaraj,
• Himangini Nigam,
• Gauri S. Agarwal,
• Beer Singh and
• Manoj K. Patra

Beilstein J. Nanotechnol. 2014, 5, 789–800, doi:10.3762/bjnano.5.91

• a photocatalyst, the CuO nanoparticles do not need any assistance of light, to attain their decontamination performance. Therefore these nanoparticles can be used for decontamination of indoor settings and for decontamination of water without UV light irradiation. Sporicidal activity against B

Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications

• Hua Bing Tao,
• Hong Bin Yang,
• Jiazang Chen,
• Jianwei Miao and
• Bin Liu

Beilstein J. Nanotechnol. 2014, 5, 770–777, doi:10.3762/bjnano.5.89

• performance. The construction of heterojunctions is a simple and effective way to enhance charge carrier separation, in which the build-in electric field across the junction could drive electrons and holes moving towards different parts of the photocatalyst, and thus improving the lifetime of charge carriers

• [11]. Numerous CN-based heterojunctions have been constructed by coupling CN with various types of photocatalysts, e.g., oxides and chalcogenides, which have shown improved photocatalytic performances [12][13][14][15][16][17][18]. However, the formation of interfacial defects at the CN/photocatalyst

• benefiting the interfacial charge transfer [19]. The formation of a smooth crystal transition would be expected at the interface of an all CN-based heterojunction. However, it is still challenging to synthesize a composite CN photocatalyst which is solely based on CN with different band structures [20

Visible light photooxidative performance of a high-nuclearity molecular bismuth vanadium oxide cluster

• Johannes Tucher and
• Carsten Streb

Beilstein J. Nanotechnol. 2014, 5, 711–716, doi:10.3762/bjnano.5.83

• enhanced by the presence of photocatalyst 1. After tirradiation = 80 min and under anaerobic conditions, virtually full dye degradation in the presence of 1 is observed ([Ind]/[Ind]0 < 3%), see Figure 2. In the absence of any photocatalyst, the dye concentration after an identical irradiation time is [Ind

• data suggest that in the 400–450 nm region, compound 1 might be employed as a homogeneous polyoxometalate photocatalyst with promising efficiencies for this compound class [5]. Recyclability of 1 To demonstrate the long-term stability and recyclability of 1, three consecutive photooxidative indigo

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• . (1) Firstly, the incident light is absorbed by the semiconductor material, known as photocatalyst. If the incident light energy is larger than the bandgap of the photocatalyst, it can absorb light energy and further excite the electrons from the valence band (VB) to the conduction band (CB), leaving

• photocatalysis, the photo-response of the transition metal oxides would be required to be within the visible light spectrum. Visible light accounts for around 43% of the electromagnetic radiation on the planet’s surface compared to approximately 5% for UV light. Therefore, an appropriate photocatalyst should

• photosensitization of semiconductors for potential applications in solar cells and photocatalysis. Another interesting phenomenon related to plasmonic metal nanoparticles is that the metal themselve may also be used as a photocatalyst for photo-oxidation or even water splitting. Carbon nanostructure as the

A visible-light-driven composite photocatalyst of TiO₂ nanotube arrays and graphene quantum dots

• Donald K. L. Chan,
• Po Ling Cheung and
• Jimmy C. Yu

Beilstein J. Nanotechnol. 2014, 5, 689–695, doi:10.3762/bjnano.5.81

• light irradiation. Keywords: anodic oxidation; graphene quantum dots; photocatalyst; photodegradation; TiO2 nanotube arrays; Introduction Semiconductor-mediated photocatalysis is a promising technique for the conversion of solar energy as well as degradation of organic pollutants in air and water [1

• photoelectrochemical water splitting [38]. In the present work, a composite photocatalyst of graphene quantum dots and TiO2 nanotube arrays (GQDs/TNAs) was fabricated by the coupling reaction between carboxyl-containing GQDs and amine-functionalized TNAs (Scheme 1). The experimental data revealed that sensitization of

• interfacial electron transfer from GQDs to TNAs is possible. Meanwhile, such a directional charge transfer promotes charge separation and reduces the probability of charge recombination, then further increases the activity of the photocatalyst. Conclusion In summary, a visible-light-driven photocatalyst was

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag₂CrO₄

• Difa Xu,
• Shaowen Cao,
• Jinfeng Zhang,
• Bei Cheng and
• Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

• potentially serve as a visible-light-driven photocatalyst. Photocatalytic activity We have measured the zeta potential of Ag2CrO4 as −15.8 mV at pH 6.8, suggesting that it is electronegative in neutral solutions. Since MB is a cationic dye, it can be easily adsorbed on the surface of Ag2CrO4 through

• electrostatic interaction. Therefore, the photocatalytic activity of the as-prepared Ag2CrO4 samples is evaluated through MB degradation under visible-light irradiation. Without any photocatalyst, no obvious MB degradation is observed under visible-light irradiation. For comparison, P25 (commercial TiO2

Enhanced photocatalytic activity of Ag–ZnO hybrid plasmonic nanostructures prepared by a facile wet chemical method

• Sini Kuriakose,
• Vandana Choudhary,
• Biswarup Satpati and
• Satyabrata Mohapatra

Beilstein J. Nanotechnol. 2014, 5, 639–650, doi:10.3762/bjnano.5.75

• summarized as follows [29][30] and are schematically illustrated in Figure 8. Yin et al. [41] prepared nanocomposites with Ag nanoparticle decorated ZnO nanorods with a core–shell structure by seed-mediated method. They have shown that Ag–ZnO is a better photocatalyst than ZnO because, firstly, the

• of repetitive tests of the photocatalytic activity of AZ510 sample for four runs. It can be clearly seen that the efficiency of the photocatalyst remains high even after four runs. The effects of citrate concentration and Ag loading on the photocatalytic efficiency can be summarized as follows. It

• dispersed in 5 mL deionized water. Aqueous MB solution was added to the photocatalyst mixture and thoroughly mixed. The reaction suspensions containing 10 μM MB and different (ZnO, Ag–ZnO) photocatalysts were irradiated with sun light for different times (10, 20, 40 min) with intermittent shaking for

High activity of Ag-doped Cd_0.1Zn_0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

• Leny Yuliati,
• Melody Kimi and
• Mustaffa Shamsuddin

Beilstein J. Nanotechnol. 2014, 5, 587–595, doi:10.3762/bjnano.5.69

• Cd0.1Zn0.9S photocatalyst. Keywords: Ag doping; Cd0.1Zn0.9S; hydrogen production; hydrothermal; visible light; Introduction The development of clean and renewable hydrogen energy through a sustainable production process is still a big issue to be addressed. Solar energy is a very attractive option as it is

• band energy required for hydrogen production. However, in order to utilize solar energy in the future, a further red shift to a range of even longer wavelengths is still highly desired. The modification of Cd1−xZnxS photocatalyst with metal ions, such as Cu [9][10][11][12][13], Ni [14][15], Sn [16

• ], and Sr [17] has been a good attempt to increase the visible-light absorption of the Cd1−xZnxS photocatalyst. The use of Ag species as a good dopant for various types of photocatalysts has been also reported [18][19][20], including its use to modify Cd1−xZnxS [21][22][23]. Cd1−xZnxS modified by Ag2S

Artificial sunlight and ultraviolet light induced photo-epoxidation of propylene over V-Ti/MCM-41 photocatalyst

• Van-Huy Nguyen,
• Shawn D. Lin,
• Jeffrey Chi-Sheng Wu and
• Hsunling Bai

Beilstein J. Nanotechnol. 2014, 5, 566–576, doi:10.3762/bjnano.5.67

• photocatalyst by using artificial sunlight (Xe lamp with/without an Air Mass 1.5 Global Filter at 1.6/18.5 mW·cm−2) and ultraviolet light (Mercury Arc lamp with different filters in the range of 0.1–0.8 mW·cm−2). This is the first report of using artificial sunlight to drive the photo-epoxidation of propylene

• . Over V-Ti/MCM-41 photocatalyst, the propylene oxide (PO) formation rate is 193.0 and 112.1 µmol·gcat−1·h−1 with a PO selectivity of 35.0 and 53.7% under UV light and artificial sunlight, respectively. A normalized light utilization (NLU) index is defined and found to correlate well with the rate of

• tested in this study. Keywords: artificial sunlight; light irradiation effects; photo-epoxidation; ultraviolet (UV) light; V-Ti/MCM-41 photocatalyst; Introduction It is agreed that light, especially its wavelength spectrum and intensity, is a crucial factor for efficient photocatalysis. A

Applicability and costs of nanofiltration in combination with photocatalysis for the treatment of dye house effluents

• Wolfgang M. Samhaber and
• Minh Tan Nguyen

Beilstein J. Nanotechnol. 2014, 5, 476–484, doi:10.3762/bjnano.5.55

• ) and patent blue (C27H31N2NaO6S2), by using TiO2 Degussa P25 as the photocatalyst in a lab-scale combined system with NF membranes NTR 7410 (Nitto Denko, Tokio) and have observed that it was possible to successfully treat concentrated solutions (500 mg/L) of both dyes by means of a continuous process

• with a suspended photocatalyst. Damodar et al. [17] have studied the coupling of a MF membrane separation with a photocatalytic laboratory slurry reactor for an advanced treatment of dye effluent and achieved high removal rates (82–100% colour removal, 45–93% TOC removal, and 50–85% COD removal) at

• . Irradiation can take place in the flat sheet membrane cell or in a separated recirculation loop. Different configurations were applied for both fixed-bed photoreactors and slurry batch photoreactors. The authors indicated that an advantage of the system with the suspended photocatalyst over the fixed one is

Dye-sensitized Pt@TiO₂ core–shell nanostructures for the efficient photocatalytic generation of hydrogen

• Jun Fang,
• Lisha Yin,
• Shaowen Cao,
• Yusen Liao and
• Can Xue

Beilstein J. Nanotechnol. 2014, 5, 360–364, doi:10.3762/bjnano.5.41

• particle bridge. Keywords: charge transfer; dye-sensitization; photocatalysis; photocatalyst; solar fuels; water splitting; Introduction Since Honda and Fujishima reported the effective hydrogen evolution from water splitting by a TiO2 and Pt electrode in a photoelectrochemical cell in the early 1970s [1

• Pt@TiO2 photocatalyst was dispersed into 10 mL of an aqueous solution containing triethanolamine (TEOA, 15 wt %) as electron donor and erythrosin B (0.2 wt %) as the photo-sensitizing dye. The suspension was sealed in a quartz vessel and purged with Argon for 30 min to remove the residual oxygen

Study of mesoporous CdS-quantum-dot-sensitized TiO₂ films by using X-ray photoelectron spectroscopy and AFM

• Mohamed N. Ghazzal,
• Robert Wojcieszak,
• Gijo Raj and
• Eric M. Gaigneaux

Beilstein J. Nanotechnol. 2014, 5, 68–76, doi:10.3762/bjnano.5.6

• . Keywords: AFM; CdS; heterojunction; particle size; quantum dots; TiO2; XPS; Introduction To sensitize the photocatalyst TiO2 with cadmium sulfide quantum dots (QDs-CdS) is a well-established concept that is of great relevance in different applications. The most popular of these applications are

• sensitize TiO2. The suitable positions of the potential energies allow for an easy transfer of the exciton between the semiconductors. Not only does that help to optimize the charge separation by reducing the recombination of charges, it also allows for an extension of the photoresponse of the photocatalyst