Heterojunction Materials Research Articles

Ni(II)-doped CuWO4 photoanodes with enhanced photoelectrocatalytic activity

CuWO4 has emerged in the last years as a ternary metal oxide material for photoanodes application in photoelectrochemical cells, thanks to its relatively narrow band gap, high stability and selectivity toward the oxygen evolution reaction, though largely limited by its poor charge separation efficiency. Aiming at overcoming this limitation, we investigate here the effects that Cu(II) ion substitution has on the photoelectrocatalytic (PEC) performance of copper tungstate. Optically transparent CuWO4 thin-film photoanodes, prepared via spin coating and containing different amounts of Ni(II) ions, were fully characterized via UV–Vis spectroscopy, XRD and SEM analyses, and their PEC performance was tested via linear sweep voltammetry, incident photon to current efficiency and internal quantum efficiency analyses. From tests performed in the presence of a hole scavenger-containing electrolyte, the charge injection and separation efficiencies of the electrodes were also calculated. Pure-phase crystalline and/or heterojunction materials were obtained with higher PEC performance compared to pure CuWO4, mainly due to a significantly enhanced charge separation efficiency in the bulk of the material.Graphic abstract

Enhanced Photocatalytic Activity of Lead‐Free Cs2TeBr6/g‐C3N4 Heterojunction Photocatalyst and Its Mechanism

AbstractIn this study, a new type of lead‐free double perovskite Cs2TeBr6 combined with metal‐free semiconductor g‐C3N4 heterojunction is constructed and used for photocatalytic CO2 reduction for the first time. The S‐scheme charge transfer mechanism between Cs2TeBr6 and g‐C3N4 is systematically verified by X‐ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) and in situ Fourier infrared spectroscopy(FT‐IR). The formation of S‐type heterojunction makes the photocatalyst have higher charge separation ability and highest redox ability. The results show that 5%‐CTB/CN heterojunction material has the best photocatalytic reduction effect on CO2 under visible light irradiation. After 3 h of illumination, the yield of CO and CH4 are 468.9 µmol g−1 and 61.31 µmol g−1, respectively. The yield of CO is 1.5 times and 32 times that of pure Cs2TeBr6 and g‐C3N4, and the yield of CH4 is doubled compared with pure Cs2TeBr6. However, g‐C3N4 almost does not produce CH4, which indicates that the construction of heterojunction helps to further improve the photocatalytic performance of the material. This study provides a new idea for the preparation of Cs2TeBr6/g‐C3N4 heterojunction and its effective interfacial charge separation.

Intermediate products driven one-pot in-situ synthesis of BiOCl/WO3 heterojunction with enhanced photocatalytic hydrogen and oxygen evolution for potential industrial applications

One-pot in-situ method was one of crucial industrial techniques to construct heterojunctions, while some intermediate reaction mechanisms of photocatalysts in this procedure were not specific enough. Herein, a new intermediate products driven one-pot in-situ method was investigated for construction of BiOCl/WO3 that applied in photocatalytic water splitting. According to some characterizations, the hydrochloric acid and water were recognized as important intermediates controlling on growth of BiOCl/WO3 heterojunction. Under significant effects of Z-scheme structure and internal electric fields, the BiOCl/WO3 showed enlarged light absorption and enhanced photo-induced carriers separation ability that its O2 and H2 evolution rates were improved effectively, in which the optimal photocatalytic O2 (994.5 µmol/g∙h) and H2 evolution activity (83.4 µmol/g∙h) were ∼2.5 and 4.5 times higher than that of the single BiOCl, respectively. Due to compact interfacial connection between BiOCl and WO3 after in-situ synthesis, the heterojunction showed a high stability and recyclability for potential industrial applications. We believe that the facile synthetic method was essential for more researches on heterojunction materials and their industrial applications.

Selective response features of MXene loaded Co9S8@In2S3 nanocomposites to triethylamine in gas mixtures

In this study, a composite heterojunction material of Ti3C2Tx MXene nanosheets with Co9S8 @In2S3 nanoparticles, named (Co9S8 @In2S3)/MXene, was constructed using a hydrothermal method. The materials were characterized and analyzed in terms of morphology, structure, and selective response properties to triethylamine gas. The materials were characterized by SEM, TEM, HAADF, STEM, XRD, XPS, BET, and other tests. The results showed a response value of 44.9 for (Co9S8 @In2S3)/20% MXene at 350 °C and 20 ppm triethylamine (TEA), with a response/recovery time of 63 s/115 s respectively. In particular, (Co9S8 @In2S3)/MXene exhibits excellent immunity to interference and a highly stable adsorption/desorption process with almost no noise interference. In addition, the (Co9S8 @In2S3)/MXene material showed stable and fast selective response to TEA in different types of gas mixtures compared with the commonly used single TEA selective response study method. The results of this study provide valuable techniques and theories for the Environmental protection application of TEA selective response materials. Finally, this article performs a comparative analysis on the mechanism of selection response and stability of (Co9S8 @In2S3)/MXene materials, and concludes that the process determining the specific response of (Co9S8 @In2S3)/MXene materials to particular gas molecules includes three processes: shape-selective adsorption, redox reaction, and charge carrier conduction.

1D/0D heterostructured ZnIn2S4@ZnO S-scheme photocatalysts for improved H2O2 preparation

Solar photocatalysis is a promising, green, and sustainable technique for the synthesis of H2O2. In this study, low-dimensional ZnO/ZnIn2S4 S-scheme heterojunction photocatalysts are fabricated using electrostatic spinning and chemical bath deposition methods for the efficient photocatalytic production of H2O2. ZnO nanofibers loaded with 20 wt% ZnIn2S4 exhibit a superior H2O2 production rate of 928 μmol g−1 h−1, which is more than four times higher than that seen in pristine hexagonal phase ZnO and ZnIn2S4. First-principles calculations and in-situ X-ray photoelectron spectroscopy reveal the charge separation and transfer mechanisms in the S-scheme heterojunction. The construction of the S-scheme heterojunction facilitates the spatial separation of charge carriers, and electrons and holes with higher redox abilities are retained. Photoelectrochemical and photoluminescence tests further show that the formation of an S-scheme heterojunction is beneficial for the separation of photoinduced charge carriers. Electrochemical tests and electron paramagnetic resonance measurements indicate that H2O2 production is primarily via a two-step single-electron O2 reduction path. This study provides a new approach for the construction of S-scheme heterojunction materials that can efficiently produce H2O2 under solar irradiation.

Prominent COF, g-C3N4, and Their Heterojunction Materials for Selective Photocatalytic CO2 Reduction

New heterojunction materials (HJs) were synthesized in-situ by molecularly bonding the monomers of a triazine-based covalent organic framework (bulk COF) on the template of exfoliated carbon nitride (g-C3N4). The photocatalysts reduced carbon dioxide to carbon monoxide in aqueous dispersions under UV irradiation. The g-C3N4 showed production of 6.50 μmol CO g−1 h−1 and the bulk COF of 2.77 μmol CO g−1 h−1. The CO yield was evaluated in sustainability photoreduction cycles and their CO2 uptake capacity and isosteric heat of adsorption were estimated. All the heterojunction photocatalysts obtained ameliorated CO production rates compared to the bulk COF. Finally, the influence of the Pt co-catalyst on the photocatalytic activities was determined without the addition of any sacrificial agent, and the COF:g-C3N4 heterojunction with the ratio of 1:10 was proven to be a photocatalytic system with an optimum and selective, CO yield of 7.56 μmol g−1 h−1.

Controllable construction of NiFe MOF/LDH heterojunction with interfacial charge transfer as efficient oxygen evolution electrocatalyst

Herein, a facile partial hydrolysis strategy has been developed to construct NiFe MOF/LDH heterojunction using NiFe MOF as the precursor. While preserving the basic structure of MOF, LDH species along with electroactive phase interfaces were in-situ generated in NiFe MOF/LDH. The obtained catalyst exhibited an ultralow overpotential of 207 mV to reach the current density of 10 mA cm−2 and performed excellent stability towards OER. Both experimental and theoretical investigations demonstrated that the strong interfacial charge transfer in NiFe MOF/LDH heterojunction could improve the conductivity and optimize the adsorption of O-intermediates, thus enhancing the OER kinetics. This study may provide a novel platform to construct heterojunction materials with interfacial charge transfer for electrocatalytic applications.

Construction of hexagonal hollow rod-shaped NiCo2O4–In2O3 p-n heterojunction for low concentration formaldehyde detection

The construction of p-n heterostructures using n-type and p-type semiconductor is a very important way to enhance gas sensing performance. In this work, hexagonal rod-shaped NiCo2O4/In2O3 with larger surface area was prepared via a simple water bath approach and subsequent calcination process. The microscopic morphology characterization results show that the NiCo2O4/In2O3 composite has a hexagonal hollow rod-shaped structure, where NiCo2O4 grows in situ on the surface of In2O3, forming p-n heterojunctions. Notably, the NiCo2O4/In2O3 composites formed with 6% NiCo2O4 addition (In-NC6) at 200 °C showed the best gas sensing performance for 1 ppm formaldehyde with a response value of 9.11 and a theoretical detection limit as low as 10.83 ppb. The rich oxygen vacancies, active site and p-n heterojunction are conducive to the adsorption of formaldehyde and electron transfer. This in situ growth approach provides novel ideas and promising prospects to synthesize other p-n heterojunction materials for applying to toxic gas detection.

Photoelectrochemical aptasensing of lincomycin based on a AgI-carboxylated multiwalled carbon nanotubes-BiOI Z-scheme heterojunction

Lincomycin (LIN) is a common antibiotic that is widely used in animal husbandry and other fields, and the residual problem caused by its abuse has attracted widespread attention. Herein, a novel AgI-carboxylated multiwalled carbon nanotubes (cMWCNT)-BiOI Z-scheme heterojunction material was synthesized via a one-pot hydrothermal method, modified on a fluorine-doped tin oxide (FTO) electrode surface, and used for detecting LIN. The photocurrent on the AgI-cMWCNT-BiOI/FTO photoelectrode is 4.6 times that on the control AgI-BiOI/FTO photoelectrode. An amino-functionalized LIN aptamer was fixed on the AgI-cMWCNT-BiOI/FTO photoelectrode by the cross-linking reaction between chitosan and glutaraldehyde, and then Ru(NH3)63+ was electrostatically attached to the LIN aptamer to increase the photocurrent response to the LIN binding. When LIN binds competitively with Ru(NH3)63+ to the aptamer, the photocurrent signal can be quantitatively decreased. Under optimized conditions, the anodic photocurrent at 0 V vs KCl-saturated calomel electrode in 0.1 M phosphate buffer (pH 7.0) containing 0.100 M ascorbic acid was linear with the common logarithm of LIN concentration from 10.0 pM to 500 nM, with a limit of detection of 2.8 pM (S/N = 3). Satisfactory recovery results were obtained in the analysis of cow milk samples.

High-performance MnSe2–MnSe heterojunction hollow sphere for aluminum ion battery

With its consistent thermal runaway temperature and superior capacity, aluminum ion batteries have emerged as a key area for battery development. At the moment, electrode material is the main focus of aluminum ion battery capacity enhancement. Selenide is anticipated to develop into a high-performance cathode for aluminum ion batteries, since it is a type of high energy density electrode material. However, because selenide is soluble in acid electrolytes, Al-Se batteries have low cycle performance and cannot keep up with the present demand for electronic gadgets. Here, homogeneous-structured precursors were created via a hydrothermal reaction, and MnSe2–MnSe heterojunction hollow spheres were created a step further via temperature control of the selenidation reaction. With 103.76 mAh/g of specific capacity remaining after 3000 cycles at 1.0 A/g, this novel heterojunction material exhibits astounding cycle stability. After additional investigation, it was shown that the MnSe2–MnSe heterojunction may prevent the dispersion of the active substances, significantly enhancing the cycle performance. The density of states (DOS) of electrode materials demonstrates the superior electronic conductivity of this heterojunction material. Meanwhile, it was computationally demonstrated that the MnSe2–MnSe heterojunction has a strong adsorption energy for AlCl4−, thus accelerating the reaction kinetics. In summary, the performance of selenides has been improved by this novel heterojunction material, which also makes for a superior cathode material.

Heterojunction photocatalyst FeS2/g-C3N5 for activating sulfites to degrade tetracycline: A stable degradation system based on heterogeneous processes

The UV/sulfite system is a promising source of •SO4− and/or •OH, but its application is largely limited by the use of UV light due to its high cost and high energy consumption. Graphite carbon nitride (g-C3N5), as a new photocatalytic material, has better visible light absorption capacity and narrower band gap than g-C3N4, which is expected to activate sulfite under visible light to solve this problem. Herein, a novel FeS2/CN heterojunction material based on g-C3N5 was constructed by hydrothermal in-situ synthesis method and successfully activated sulfite, which was confirmed by tetracycline degradation experiments in water. Under optimized conditions, the degradation rate of TC in 1 h reached 96%. The experimental results revealed that the FeS2/CN heterostructure enhances the absorption of visible light and inhibits the recombination of carriers, enabling more electrons and holes to be utilized. Holes play a major role in the degradation reaction, promote the sulfite chain reaction, and effectively regulate the cycle of Fe2+ and Fe3+ in the solution. Iron ion leaching is negligible and the degradation reaction remains stable at pH 5–9.

Hollow Starlike Ag/CoMo-LDH Heterojunction with a Tunable d-Band Center for Boosting Oxygen Evolution Reaction Electrocatalysis.

It is a challenging task to utilize efficient electrocatalytic metal hydroxide-based materials for the oxygen evolution reaction (OER) in order to produce clean hydrogen energy through water splitting, primarily due to the restricted availability of active sites and the undesirably high adsorption energies of oxygenated species. To address these challenges simultaneously, we intentionally engineer a hollow star-shaped Ag/CoMo-LDH heterostructure as a highly efficient electrocatalytic system. This design incorporates a considerable number of heterointerfaces between evenly dispersed Ag nanoparticles and CoMo-LDH nanosheets. The heterojunction materials have been prepared using self-assembly, in situ transformation, and spontaneous redox processes. The nanosheet-integrated hollow architecture can prevent active entities from agglomeration and facilitate mass transportation, enabling the constant exposure of active sites. Specifically, the powerful electronic interaction within the heterojunction can successfully regulate the Co3+/Co2+ ratio and the d-band center, resulting in rational optimization of the adsorption and desorption of the intermediates on the site. Benefiting from its well-defined multifunctional structures, the Ag0.4/CoMo-LDH with optimal Ag loading exhibits impressive OER activity, the overpotential being 290 mV to reach a 10 mA cm-2 current density. The present study sheds some new insights into the electron structure modulation of hollow heterostructures toward rationally designing electrocatalytic materials for the OER.

Rationally designed C3N4/ TiO2 (anatase/brookite) heterojunction for enhanced photocatalytic hydrogen generation under visible light

In this study, C3N4 was prepared using the polycondensation method, and TiO2 (ansate/Brookite) was synthesized using the solvothermal method. These materials were subsequently utilized to prepare C3N4/TiO2 heterojunction materials via the photoanchoring method, with the aim of improving photocatalytic hydrogen production. The physical, chemical, and optical properties of the composites were investigated to verify the formation of heterojunctions, as well as to assess the impact of varying levels of C3N4 content (1%, 5%, and 10%) in the C3N4/TiO2 composite on hydrogen production. Notably, the composite with 5% C3N4 demonstrated superior photocatalytic hydrogen production (approximately 692 μmol h-1 g-1), and the underlying reasons were elucidated using photoelectrochemical characterization. To establish the band alignment of C3N4 and TiO2 before and after contact, a comprehensive array of techniques was employed, encompassing Kelvin force microscopy to acquire work functions, UV–Vis spectral analysis to ascertain band gaps, XPS valence spectra to identify the Valence Band Maxima, and the Kraut method to calculate Band Offsets. These analyses revealed that the formation of the heterojunction is staggered in nature. Finally, utilization of ESR analysis has conclusively verified that the charge transfer mechanism inherent in the C3N4/TiO2 heterojunction adheres to the Z-scheme.

Synergistic effect of bimetallic cobalt-based sulfide enhances the performance of ZnSe photocatalytic hydrogen evolution by Z-scheme

In this work, ZnSe/ZnCo2S4 (ZCS) composites were synthesized by simple hydrothermal method and Z-scheme heterojunctions were formed. Under the simulated sunlight environment, The results show that the hydrogen production efficiency of 70 wt% ZnSe/ZCS composites was as high as 3402.4 μmol·g−1·h−1, which is 4.37 and 94.44 times that of ZnSe and ZCS monomers, respectively, and the apparent quantum efficiency (AQY) reaches 10.5%. Among them, the Z-scheme heterojunction improves the redox ability of the material, which is more conducive to charge separation, and ZCS also promotes absorption of visible light of ZnSe/ZCS. In addition, the Z-scheme heterojunction structure and material stability were verified by XPS, ESR.This work provides a new way to improve ZnSe in the field of photocatalytic hydrogen evolution.

Facile synthesis of MoS2/SnS2/NC heterojunction nanosphere composite as high-performance anode material for sodium-ion batteries

SnS2 is considered a potential anode material for sodium-ion batteries (SIBs) due to its high theoretical capacity, abundant resources and non-toxic properties. However, the low Na+ diffusion kinetics and large volume expansion of SnS2 hinder further development and application. Hence, the heterostructured MoS2/SnS2/NC nanospheres are synthetized through a facile hydrothermal reaction. By coating SnS2 on MoS2 templates, the heterojunction composite MoS2/SnS2/NC combines the advantages of the highly stable nanosphere structure of MoS2 and the high theoretical capacity of SnS2. In conclusion, it delivers a high specific capacity of 603 mAh g−1 at 10 A g−1 after 2000 cycles and excellent rate performance of 750 mAh g−1 at 0.1 A g−1. Furthermore, the full-battery of MoS2/SnS2/NC= |Na3V2(PO4)3 exhibits a great capacity of 69.8 mAh g−1 at 100 mA g−1 after 100 cycles. The excellent electrochemical performance of the heterojunction material proves it to be an extraordinary anode material for SIBs.

Fabricated ZnO@ZnIn2S4 S-scheme heterojunction photocatalyst for enhanced electron-transfer and CO2 reduction

Step-scheme (S-scheme) heterojunctions can efficiently promote the separation of photogenerated carriers while maintaining the strong oxidation/reduction ability of photocatalysts; thus, research attention on S-scheme heterojunctions is increasing year by year. In this study, the S-scheme ZnO@ZnIn2S4 (ZnO@ZIS) heterojunction was prepared successfully. Then, electron spin resonance (ESR) characterization was applied to prove the successful construction of the S-scheme heterojunction. Photoluminescence (PL), time-resolved photoluminescence (TRPL), and photoelectrochemical experiments have demonstrated efficient interfacial charge transport in ZnO@ZIS. Finally, the mechanism of CO2 activation and electron transport was investigated by in situ Fourier transform infrared spectroscopy (FT-IR) and discrete Fourier transform (DFT) calculation analysis. The 40-ZnO@ZIS composite showed the best activity under light, and its CO and CH4 yields reached 39.76 and 3.92 μmol∙g−1∙h−1, respectively. This study provides a solution for optimizing the photocatalytic reduction activity of semiconductor photocatalysts by constructing S-scheme heterojunction materials to improve the CO2 reduction capacity.

Enhancing Photocatalytic Pollutant Degradation through S-Scheme Electron Transfer and Sulfur Vacancies in BiFeO3/ZnIn2S4 Heterojunctions

Photocatalytic degradation plays a crucial role in wastewater treatment, and the key to achieving high efficiency is to develop photocatalytic systems that possess excellent light absorption, carrier separation efficiency, and surface-active sites. Among various photocatalytic systems, S-type heterojunctions have shown remarkable potential for efficient degradation. This work delves into the construction of S-type heterojunctions of ternary indium metal sulfide and bismuth ferrite nanofibers with the introduction of sulfur vacancy defects and morphology modifications to enhance the photocatalytic degradation performance. Through the impregnation method, BiFeO3/ZnIn2S4 heterojunction materials were synthesized and optimized. The 30% BiFeO3/ZnIn2S4 heterojunction exhibited superior photocatalytic performance with higher sulfur vacancy concentration than ZnIn2S4. The in-situ XPS results demonstrate that the electrons between ZnIn2S4 and BFO are transferred via the S-Scheme, and after modification, ZnIn2S4 has a more favorable surface morphology for electron transport, and its flower-like structure interacts with the nanofibers of BFO, which has a further enhancement of the reaction efficiency for degrading pollutants. This exceptional material demonstrated a remarkable 99% degradation of Evans blue within 45 min and a significant 68% degradation of ciprofloxacin within 90 min. This work provides a feasible idea for developing photocatalysts to deal with the problem of polluted water resources under practical conditions.

Manipulation of Charge Delocalization in a Bulk Heterojunction Material Using a Mid-Infrared Push Pulse.

In organic bulk heterojunction materials, charge delocalization has been proposed to play a vital role in the generation of free carriers by effectively reducing the Coulomb attraction via an interfacial charge transfer exciton (CTX). Pump-push-probe (PPP) experiments produced evidence that the excess energy given by a push pulse enhances delocalization, thereby increasing photocurrent. However, previous studies have employed near-infrared push pulses in the range ∼0.4-0.6 eV, which is larger than the binding energy of a typical CTX. This raises the doubt that the push pulse may directly promote dissociation without involving delocalized states. Here, we perform PPP experiments with mid-infrared push pulses at energies that are well below the binding energy of a CTX state (0.12-0.25 eV). We identify three types of CTXs: delocalized, localized, and trapped. The excitation resides over multiple polymer chains in delocalized CTXs, while it is restricted to a single chain (albeit maintaining a degree of intrachain delocalization) in localized CTXs. Trapped CTXs are instead completely localized. The pump pulse generates a "hot" delocalized CTX, which promptly relaxes to a localized CTX and eventually to trapped states. We find that photo-exciting localized CTXs with push pulses resonant to the mid-infrared charge transfer absorption can promote delocalization and, in turn, contribute to the formation of long-lived charge separated states. On the other hand, we found that trapped CTXs are non-responsive to the push pulses. We hypothesize that delocalized states identified in prior studies are only accessible in systems where there is significant interchain electronic coupling or regioregularity that supports either inter- or intrachain polaron delocalization. This, in turn, emphasizes the importance of engineering the micromorphology and energetics of the donor-acceptor interface to exploit the full potential of a material for photovoltaic applications.

Highly Selective and ppb-Level Butanone Sensors Based on SnO2/NiO Heterojunction-Modified ZnO Nanosheets with Electron Polarity Transport Properties.

Gas sensors require the construction of composites with high reactivity to reduce the detection limit, but this can lead to a broad-spectrum response between the adsorbed oxygen and the target gas, making it difficult to improve selectivity. In this study, the phenomenon of electron polar transport properties of the two-dimensional heterojunction material is first discovered in gas sensing and utilized to greatly improve the selectivity of butanone sensors. Ultra-thin porous ZnO nanosheets modified with SnO2/NiO heterogeneous particles are synthesized to achieve 20 ppb detection limits for butanone with a response of 328 to 100 ppm butanone, which is the lowest known detection limit. The combination of reaction kinetics and liquid chromatography-mass spectrometry reveals a good synergistic catalytic effect of SnO2/NiO heterogeneous particles, which may contribute to the high response and low detection limit of butanone. Finally, the possible mechanism for the generation of electron polar transport phenomenon is analyzed in the two-dimensional heterojunction material. This work provides a novel perspective for achieving both selectivity and detection limits in gas sensors, with universal applicability and application potential.

Development of a molecularly imprinted photochemical sensor based on Bi2O3/TiO2 NTs heterojunction extended-gate field-effect transistor for the determination of trace neomycin

A novel extended-gate field-effect transistor based molecularly imprinted polymer photoelectrochemical (EGFET-MIP-PEC) sensor was constructed for the detection of neomycin in meat samples. Bi2O3/TiO2 NTs heterojunction materials were synthesized by anodic oxidation and electrodeposition. With neomycin as the template and 3-aminophenylboronic acid as the functional monomer, a molecularly imprinted film was prepared on the Bi2O3/TiO2 NTs electrode by electropolymerization. The MIP/Bi2O3/TiO2 NTs electrode was connected to an extended-gate field-effect transistor. Under the irradiation of xenon lamp simulated visible light, the holes generated on the MIP/Bi2O3/TiO2 NTs electrodes oxidize the neomycin adsorbed by the molecularly imprinted film, generating a photovoltage, which causes the gate voltage of the extended-gate field-effect transistor to change, thereby increasing the source-drain current. The sensor showed good linearity with the source-drain current in the neomycin concentration range of 5.0 × 10−13–5.0 × 10−8 mol L−1, with a detection limit of 1.0 × 10−13 mol L−1(3σ/S). Owing to the amplification of EGFET on photoelectrochemical signal produced by the Bi2O3/TiO2 NTs heterojunction with high photoelectric conversion efficiency and wider wavelength range of optical response, the sensitivity of the sensor was significantly improved. The selectivity of the sensor was remarkably enhanced due to the MIP film.