Ternary Heterojunction Research Articles

Surface engineering of CdS with ternary Bi/Bi2MoO6-MoS2 heterojunctions for enhanced photoexcited charge separation in solar-driven hydrogen evolution reaction

Solar driven hydrogen (H2) evolution reaction based on transition metal chalcogenides still suffers great challenges, which should realize strong visible light harvesting, photoinduced charge carriers generation and separation and the abundant reactive sites. Here, we report a proficient and scalable single-step growth of Bi/Bi2MoO6-MoS2 ternary heterojunctions on CdS nanorods using ethylene glycol mediated solvothermal growth for the first time and their application in solar energy conversion reactions. The obtained CdS-Bi/Bi2MoO6-MoS2 quaternary heteronanostructures resulted from the integration of multiple components into a single nanoarchitecture, which can precisely offer efficient charge carriers separation via different heterojunctions, enhanced visible light harvesting and suppressed electron-hole recombination. Thus, CdS-Bi/Bi2MoO6-MoS2 shows excellent H2-evolution activity of 2185 μmol/g/h, which is ten and fifteen times greater than CdS and Bi2MoO6 alone respectively. Moreover, CdS-Bi/Bi2MoO6-MoS2 photocatalyst displays good stability and recycle capability, demonstrating a promising photocatalyst for efficient H2 evolution reactions.

Exciton Dissociation on Double Z‐scheme Heterojunction for Photocatalytic Application

AbstractConstructing heterojunction is one of the promising approaches to obtain desired photocatalysts with enhanced photocatalytic activity. Herein, we have fabricated a Fe2O3‐PrFeO3/g‐C3N4 ternary heterostructure by a simple wet chemical method to improve the photocatalytic activity of pristine g‐C3N4. The as‐prepared catalyst has shown 7.8 times higher photocatalytic degradation of dye acid violet 7 and generated 379.29 μmolL−1 h−1 of ammonia under visible‐light irradiation. The ternary heterojunction was found to form a double Z‐scheme heterojunction that facilitates interfacial electron transfer, promotes the separation of photogenerated charge carriers, and also enhances light harvesting property. The enhanced photocatalytic performance of the catalyst is ascribed to the formation of double Z‐scheme heterojunction, which offers low charge transfer resistance thereby lowering the recombination of photoexcitons and increasing the lifetime of photoexcitons.

Enhanced photoactivity of ZnPc@WS2 heterojunction by CuBi2O4 and its application for photoelectrochemical detection of 5-formyl-2′-deoxycytidine

The endogenous epigenetic marker 5-formylcytosine (5 fC) is introduced by 5-methylcytosine (5 mC) oxidation under action of enzyme oxidation, and plays an important role in many life activities. Since the content of 5 fC in mammalian tissues and cells is very low, it is necessary to exploit a sensitive and specific detection method to further understand the function of 5 fC. In this work, a sensitively and selectively photoelectrochemical (PEC) biosensor was developed for 5-formyl-2′-deoxycytidine (5fdC) detection. CuBi2O4/ZnPc@WS2 was used as photoactive material, where the formed ternary heterojunction structure greatly enhanced the PEC response and increased the detection sensitivity. Positively charged polyethyleneimine (PEI) was employed as 5fdC recognition and capture unit, where the amine group on PEI specifically reacted with aldehyde group of 5fdC to form stable amide bond. 4-Carboxyphenylboronic acid (4-CPBA) was adopted as crosslinker for 5fdC and amino functionalized CuBi2O4 based on the covalent interaction between 1,3-diol bond on 5fdC and boric acid structure on 4-CPBA, and the covalent interaction between –COOH on 4-CPBA and –NH2 on amino functionalized CuBi2O4. On the basis of the positive synergistic effect of ZnPc and CuBi2O4 on improving the photoelectric performance of WS2, the separation of photo-generated electron-hole pairs in semiconductors were promoted, and the examination range was expanded from 0.1 to 500 nM, and the detection limit was 0.0483 nM (3σ). Based on the unique covalent reaction between –NH2 and –CHO, the PEC biosensor has excellent detection sensitivity, and can even separate 5fdC from 5-methylcytosine deoxyribonucleoside and 5-hydroxymethylcytosine deoxyribonucleoside. The effect of antibiotics and heavy metals on the 5fdC content in wheat tissue genome has also been further investigated using this sensor.

Facile construction TiO2/ZnIn2S4/Zn0.4Ca0.6In2S4 ternary hetero-structure photo-anode with enhanced photo-electrochemical water-splitting performance

Constructing hetero-junction on TiO2 is an effective way to overcome the fast charge recombination and slow charge transfer kinetics, but how to design the junction is still a significant challenge in photo-electrochemical (PEC) water splitting. In this study, a considerable improvement in PEC performance for TiO2 nanotubes was achieved following the introduction of a ternary hetero-junction through depositing ZnIn2S4 (ZIS) and Zn0.6Ca0.4In2S4 (ZCIS) in sequence via a facile hydrothermal method (TiO2/ZIS/ZCIS). The optimized photo-anode exhibited a photocurrent density of 1.07 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE), to be 3.96 and 1.25 times enhanced compared to that of TiO2 and TiO2/ZIS, respectively. Meanwhile, the incident photon-to-current conversion efficiency (IPCE) and applied bias photon-to-current efficiency (ABPE) of TiO2/ZIS/ZCIS were also increased in contrast with its counterparts. The merits of appropriate band alignment of TiO2, ZIS, and ZCIS and fewer interface defects built an internal electric field among the ternary hetero-junction, leading to an enhanced conductivity and efficient interface charge separation. These results were supported by a series of photo-electrochemical measurements. Among others, the shortened average lifetime of photo-generated electron-hole pairs from 1.51 (TiO2) to 1.17 ns (TiO2/ZIS/ZCIS) according to time-resolved photoluminescence reveals that the charge carriers generated in TiO2 would have an additional decay pathway in the hetero-structure, which benefits for the charge separation. Our strategy could be extended to many low-efficiency semiconductors for the design and synthesis of effective photo-anodes in PEC water splitting.

Double Z-scheme system of α-SnWO4/UiO-66(NH2)/g-C3N4 ternary heterojunction with enhanced photocatalytic performance for ibuprofen degradation and H2 evolution

In this work, we successfully prepared regular hexagonal prism porous structure g-C3N4 (CN), and designed α-SnWO4 and UiO-66(NH2) on porous CN for constructing novel ternary α-SnWO4/UiO-66(NH2)/g-C3N4 (α-SW/UNCN) hybrid photocatalyst by solvothermal approach. The α-SW75/UNCN composite showed better photocatalytic performance, and the removal rate of Ibuprofen (IPF) reached 95.5% within 2 h and the H2 evolution efficiency reached 2105μmolg−1h−1 under simulated sunlight, which were 2.5 times and 21 times higher than those of α-SW (42.5% and 105μmolg−1h−1). The TOC removal efficiency of IPF can reach to 29%, showing higher mineralization ability compared with α-SW. In addition, the trapping experiment and ESR experiment proved that •O2- and •OH radicals played most important part in the photodegradation of IPF pollutants. The improved photocatalytic performance of α-SW/UNCN was owing to the construction of n-p-n type double Z-scheme heterojunction which enhanced carries separation. This work will provide a method for preparing novel and efficiency ternary composite catalyst for antibiotic contaminant degradation and H2 production.

Double Z-scheme FeVO4/Bi4O5Br2/BiOBr ternary heterojunction photocatalyst for simultaneous photocatalytic removal of hexavalent chromium and rhodamine B

HypothesisFabrication of the heterojunction photocatalyst with appropriate band potentials as a promising method of inhibiting electron-hole pair recombination leading to enhanced photocatalytic properties. ExperimentsHerein, BiOBr, Bi4O5Br2, and binary BiOBr/Bi4O5Br2 composite were selectively synthesized by employing a one-step microwave irradiation method. Then, double Z-scheme FeVO4/Bi4O5Br2/BiOBr ternary composites with different weight percentages (%wt) of FeVO4 were fabricated and their photocatalytic applications were studied. The photodegradation of organic compounds (rhodamine B (RhB), methylene blue (MB) and salicylic acid (SA)), along with the photoreduction of hexavalent chromium (Cr(VI)) were investigated. FindingsComparing with the single and binary photocatalysts, and a commercial TiO2, the 1 %wt-FeVO4/Bi4O5Br2/BiOBr photocatalyst demonstrated superior visible-light-driven photocatalytic performance. In a Cr(VI)/RhB combined system, Cr(VI) photoreduction was further improved and coexisting RhB molecules were simultaneously degraded. Removal of Cr(VI) and RhB were maximized by adjusting both pH values and catalyst dosages. Based on UV–vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, electrochemical investigations, active-species trapping, nitrotetrazolium blue transformation, and silver photo-deposition experiments, a double Z-scheme charge transfer mechanism with an RhB-sensitized effect was proposed. This special mechanism has led to significant enhancement in charge segregation and migration, along with higher redox properties of the ternary composite, which were responsible for the excellent photocatalytic activity.

Z-Scheme Core–Shell meso-TiO2@ZnIn2S4/Ti3C2 MXene Enhances Visible Light-Driven CO2-to-CH4 Selectivity

Solar photocatalysis has long relied on the rational design of semiconductor photocatalysts. Herein, a ternary meso-TiO2@ZnIn2S4/Ti3C2 MXene photocatalyst is prepared and demonstrated with a core–shell structure accompanied by few-layered Ti3C2 Mxene on the ZnIn2S4 shell. The success of the synthesis depends on a two-step method consisting of hydrothermal and electrostatic self-assembly procedures. The ternary heterojunction exhibits a good behavior for photocatalytic CO2 reduction. A mechanism study of the photocatalytic reaction indicates that the photogenerated charges transfer in a Z-scheme pathway. Moreover, the construction of the Schottky junction between metallic Ti3C2 and TiO2@ZnIn2S4 is extremely effective for the reduction reaction. Consequently, the photocatalytic rates toward CO and CH4 production are up to 30.5 and 34.0 μmol/g within 3 h of illumination by simulated sunlight, respectively, while the CH4 selectivity reaches 52.7%. This work provides a good strategy to achieve highly efficient photocatalytic CO2 reduction.

Facile synthesis of sphere-like structured ZnIn2S4-rGO-CuInS2 ternary heterojunction catalyst for efficient visible-active photocatalytic hydrogen evolution

Photocatalysis is a promising approach for generating hydrogen, an eco-friendly and cost-effective fuel. It is hypothesized that the ternary catalyst ZnIn2S4-rGO-CuInS2, prepared by ultrasonication method, should be effective for optimized photocatalytic hydrogen generation in a Na2S/Na2SO3−water mixture. The as-synthesized catalyst was characterized using various surface analytical and optical techniques. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy analyses revealed that marigold-like structured ZnIn2S4 and layer-structured CuInS2 were dispersed on the reduced graphene oxide sheets. The ternary ZnIn2S4-rGO-CuInS2 system showed enhanced photocatalytic H2 production compared to pure ZnIn2S4, CuInS2, ZnIn2S4-rGO, CuInS2-rGO, and ZnIn2S4-CuInS2 catalysts under visible light illumination. The fabricated ZnIn2S4-rGO-CuInS2 catalyst afforded hydrogen generation of 2531 μmol/g after 5 h. The enhanced performance of the ZnIn2S4-rGO-CuInS2 catalyst originates from the synergetic effect with rGO as the electron transfer medium, and is confirmed by photocurrent density and photoluminescence measurements that indicate reduced recombination between the excited electron and hole pairs, and fast electron transfer in the ternary composite. The excellent performance of the ZnIn2S4-rGO-CuInS2 catalyst for up to three consecutive cycles was demonstrated in cyclic stability tests under visible-light illumination.

Graphitic carbon nitride nanosheet/metal-organic framework heterostructure: Synthesis and pollutant degradation using visible light

The construction of binary and ternary heterojunctions has gathered attention in water remediation applications. Herein, g-C3N4, MIL-101(Fe), and MIL-101(Fe)/g-C3N4 binary composite were synthesized by in-situ growth of MIL-101(Fe) crystals along with the nanosheets of g-C3N4. The materials have been characterized by XRD, FTIR, SEM, EDS, DRS, PL, and BET/BJH. The highest degradation efficiency achieved using MIL-101(Fe)/g-C3N4 nanocomposite was 99.3% while the pristine g-C3N4 degraded only 40% of the pollutants by photocatalyst dosage = 0.005 g, pH = 4.8, and irradiation time = 90 min condition. This enhanced photocatalytic performance might be attributed to improved optical properties and quenched recombination rate of photogenerated electron-hole pairs utilizing the heterojunctions built during the synthesis process. The size of MIL-101(Fe) crystals diameters are in the range of 70–120 nm. The MIL-101(Fe)/g-C3N4/visible light/H2O2 systems obey the zero-order kinetics while the pristine g-C3N4 and Fe-MIL-101(Fe) obey second-order and first-order kinetics, respectively. It is obvious that the introduction of g-C3N4 nanosheets in the synthesis procedure of MIL-101(Fe), significantly affects the kinetics of RhB degradation in the presence of H2O2 under visible light. The pathway in which the photocatalytic reaction takes place was demonstrated to be the Z-scheme mechanism.

Heterojunction engineering at ternary Cu2S/Ta2O5/CdS nanocomposite for enhanced visible light-driven photocatalytic hydrogen evolution

Photocatalytic H2 production has been successfully achieved using a novel Cu2S/Ta2O5/CdS ternary nanocomposite fabricated by a solid-state approach. Initially, a solvent-assisted chemical approach was adopted for the synthesis of morphology controlled Cu2S (six petals) and CdS (nanorods) nanostructures. The known sol-gel method was used to synthesize the Ta2O5 nanoparticles, and then the composition was optimized for suitable engineering at the ternary heterojunction. The electron microscopic analysis evidenced the presence of ternary nanocomposite consists of Cu2S, CdS, and Ta2O5 with six-petals, nanorods, and random-spherical morphology, respectively. The effect of solution pH and optimization of the catalyst dosage over the photocatalytic H2 has been described. Photocatalytic experiments were carried out under standard conditions and rate of H2 generation in the following order of Lactic acid > Triethanolamine > Na2S/Na2SO3 in an aqueous solution. The optimized Cu2S/Ta2O5/CdS nanocomposite demonstrated a high rate of H2 evolution of 131 mmol.h−1.g−1cat that is significantly higher than the pristine CdS, Cu2S, CdS/Ta2O5, and Cu2S/CdS composites. The appropriate conduction band position of selected materials with multistep charge transfer setbacks the charge recombination process and resulted in durable enhanced efficiency with the visible light to the H2 conversion efficiency of 5.6%. Moreover, the stability of the spent catalyst was analyzed chemically as well as structurally.

Construction of hierarchical CuBi2O4/Bi/BiOBr ternary heterojunction with Z-scheme mechanism for enhanced broad-spectrum photocatalytic activity

A novel Z-scheme CuBi2O4/Bi/BiOBr ternary heterostructured photocatalyst was developed by a simple hydrothermal method. The structural, morphologic, optical and electronic properties were systematacially characterized. The metal Bi was confirmed by the XRD, XPS and SEM, which served as bridge between CuBi2O4 and BiOBr, promoting the charge transfer. The optimized CuBi2O4/Bi/BiOBr heterostructure possessed superior photocatalytic degradation efficiency (81%) towards ciprofloxacin (CIP), which was 2.38- and 1.25-fold higher than that of pure CuBi2O4 and BIOB, respectively. The origin of the improved photocatalytic performance of CuBi2O4/Bi/BiOBr heterostructure was attributed to the enhanced light absorption combined with Z-scheme heterostructure. Additionally, the degradation efficiencies of CuBi2O4/Bi/BiOBr heterostructure towards Methylene blue (MB), Lanasol Red 5B (LR5B), Rhodamine B (RhB), Bisphenol A (BPA) and phenol were 73%, 99%, 99%, 45% and 48%, respectively. However, the simultaneous photocatalytic degradation exhibited the competitive actions between CIP and other organic pollution for radical, resulting in poor degradation performance for CIP. The experimental factor towards degradation efficiency of CIP was investigated. The momentous contribution of superoxide radicals (•O2−) and hydroxyl radical (•OH) were confirmed by the trapping experiment and electron paramagnetic resonance (EPR), which help us deduce Z-scheme charge transfer mechanism, improving the photocatalytic activity.

Construction of ternary heterojunction AgI/C-MoS2 nanosheets with enhanced visible-light photocatalytic property and self-cleaning performance

Construction of ternary heterojunction AgI/C-MoS2 nanosheets with enhanced visible-light photocatalytic property and self-cleaning performance

Engineering 2D compressed layered g-C3N4 nanosheets by the intercalation of BiVO4-Bi2WO6 composites for boosting photocatalytic activities

The traditional bulk graphitic carbon nitride has disadvantages of weak visible light absorption ability and fast charge carrier recombination speed, which greatly limit its further industrial application. In this work, we successfully construct a new ternary heterojunction photocatalyst that 2D compressed layered g-C3N4 nanosheets (CNNs) are modified by the intercalation of BiVO4-Bi2WO6 composites (CVW-I) through one-step hydrothermal method, in which the bismuth precursors are introduced and confined in the interlayer of CNNs and hence the compressed adjacent layers are formed simultaneously in CNNs. Since the close contact of different components with compressed carbon nitride layers, the built-in electric field is relatively formed and the recombination rate between photogenerated electrons and holes is remarkably suppressed. Attributing to these improvements, the as-constructed CVW-I composite achieves more striking photocatalytic activity, and the rate constant of CVW-I reached the highest values for RhB and TC degradation (k = 0.058 min−1 and 0.048 min−1), which are 4.5 and 3.6 times higher than those of carbon nitride, respectively.

Porous loofah-sponge-like ternary heterojunction g-C3N4/Bi2WO6/MoS2 for highly efficient photocatalytic degradation of sulfamethoxazole under visible-light irradiation

A novel porous loofah-sponge-like ternary heterojunction g-C3N4/Bi2WO6/MoS2 (CN-BM) was prepared via a facile method. The introduction of binary Bi2WO6/MoS2 into g-C3N4 could be qualified for constructing reasonable heterostructure while regulating photocatalysts morphology. Benefiting from the unique structure, the ternary heterojunction composites not only inhibited the agglomeration but also exhibited the prominent visible-light harvest capacity and abundant active sites, which could accelerate the photogenerated carriers separation and preserve the robust redox ability. The results showed that the optimized sample (CN-BM2) displayed the excellent degradation efficiency of sulfamethoxazole (SMX) under visible-light irradiation (over 99% within 60 min), and the fitted pseudo-first-order kinetic rate constant reached to 0.089 min−1, where it was 3.17 times than that of pure CN. Additionally, the radical scavenger experiments and electron spin resonance experiments indicated that the active species super-oxide radical and hole played a major role in the degradation experiment. The charge transfer mechanism was proposed and the main intermediates indicated that the active radicals attacked on the benzene ring and isoxazole ring in SMX, and further mineralized to inorganic molecules eventually.

Visible light responsive TiO2 - graphene oxide nanosheets - Zn phthalocyanine ternary heterojunction assisted photoelectrocatalytic degradation of Orange G

Herein, we report on the successful fabrication of a visible light-responsive TiO2 - graphene oxide nanosheets – Zn phthalocyanine (TiO2@GONS@ZnPc) ternary structure for the photoelectrochemical degradation of Orange G azo dye. The characterization of TiO2@GONS@ZnPc composite was achieved using various spectroscopic and microscopic techniques. Our results show that the TiO2@GONS@ZnPc surface hybrid heterojunction promotes charge separation and electron migration, significantly improving the degradation efficiency with an applied potential. For the first time, we show the existence of a non-radical activation route for persulfate (PS) using such π electron-rich ZnPc-GONS catalysts. The degradation kinetics were found to follow pseudo first order kinetics. Electron spin resonance analyses suggested that neither hydroxyl radicals nor sulfate radicals were produced therein, and therefore were not responsible for the persulfate-driven oxidation of the OG dye. These findings suggest that both which GONS and ZnPc play a critical role in mediating the eventual charge transfer mediated PS activation. The results illustrate the remarkable capacity of the TiO2@GONS@ZnPc composite to rapidly degrade Orange G by a coupled TiO2@GONS@ZnPc-persulfate system.

G-C3N4/Ag3PO4 based binary and ternary heterojunction for improved photocatalytic removal of organic pollutants

ABSTRACT Ag3PO4 (AP) was effectively coupled with bare and modified graphitic carbon nitride through a facile wet-chemistry process for the development of hybrid organic/inorganic heterojunctions. The prepared materials were thoroughly characterised using a multimethodology approach including XRD, IR, DR-UV-Vis, nitrogen adsorption/desorption isotherms, photoluminescence and EPR spectroscopy. The photoactive hybrid materials were applied as photocatalysts for the degradation of organic pollutants, namely rhodamine B (RhB), under pure visible light irradiation. The prepared nanocomposites were proven stable under working conditions and more active than their individual counterparts. The study highlighted the importance of CN modification and the development of preformed Ag nanoparticles in photoactivity. The enhanced activity is attributed to the improved charge separation efficiency as evidenced by PL due to the formation of a heterojunction. In-situ EPR spin-trap experiments provide direct evidence for the formation of a Z-scheme heterojunction through the detection of superoxide anion radicals (). Finally, a photocatalytic mechanism is proposed based on the spectroscopic data and reference reactions using sacrificial agents to identify the predominant active species.

Promoted photocatalytic degradation and detoxication performance for norfloxacin on Z-scheme phosphate-doped BiVO4/graphene quantum dots/P-doped g-C3N4

• A ternary Z-scheme heterojunction BiVO 4 /GQDs/PCN is fabricated. • BiVO 4 /GQDs/PCN exhibits excellent visible light photodegradation activity for norfloxacin. • GQDs act as electron mediator to promote interfacial charge transfer. • Enhanced mineralization ability and detoxication performance can be achieved. • Degradation pathway, toxicity of intermediates and reaction mechanism are discussed. A novel kind of Z-scheme ternary heterojunctions phosphate-doped BiVO 4 /graphene quantum dots/P-doped g-C 3 N 4 (BVP/GQDs/PCN) were fabricated for the visible light degradation of norfloxacin (NOR), a typical antibiotic. Compared with binary type-II heterojunction phosphate-doped BiVO 4 /PCN (BVP/PCN), Z-scheme BVP/GQDs/PCN exhibited promoted interfacial charge transfer efficiency and broadened visible light response range, endowing them with excellent photodegradation activity and mineralization ability in NOR degradation. A high NOR degradation rate of 86.3% with a removal rate of total organic carbon (TOC) of 55.8% can be achieved over BVP/GQDs/PCN for 120 min visible light irradiation, which is an excellent performance compared with ever reported similar photocatalysts. In particular, because of the enhanced redox ability of photogenerated charges and the generation of multiple active species (eg. OH and O 2 − ) over Z-scheme photocatalytic system, the accumulation of highly toxic degradation intermediates was greatly inhibited, and a better detoxication performance was obtained compared to PCN and BVP/PCN. This work may shed light on the inhibition of highly toxic degradation intermediates of antibiotics by regulating the charge transfer mechanism, photocatalytic active species, and the degradation pathway of antibiotics.

Fabrication of CdS/ZnS/g-C3N4 Composites for Enhanced Visible-Light Photocatalytic Degradation Performance

Constructing a heterojunction is an ideal way to modify the photocatalytic efficiency of semiconductor photocatalysts. In this paper, CdS/ZnS/g-C3N4 (CZG) ternary composites with different mass ratio of CdS (10%, 20%, 30%) were prepared by cation exchange method using as-synthesized ZnS/g-C3N4 and Cd(NO3)2·6 H2O as the starting materials. The composition and optical properties were investigated by XRD and photoluminescence spectra (PL). The results showed the ternary heterojunctions possessed faster photo-induced electrons/holes separation efficiency. The photocatalytic experiments exhibited that the obtained ternary composite materials exhibited enhanced visible-light photodegradation efficiency for the degradation of MO aqueous solution. Among the ternary composite materials, the CZG-10% composite displayed the highest photocatalytic performance of 68.52%. The enhanced photodegradation efficiency could be ascribed to the reasonable design of the heterojunction.

Nonylphenol photodegradation by novel ternary MIL-100(Fe)/ZnFe2O4/PCN composite under visible light irradiation via double charge transfer process

Nonylphenol (NP) residues, as a typical endocrine disrupting chemical (EDC), frequently exist in sewage, surface water, groundwater and even drinking water, which poses a serious threat to human health due to its bioaccumulation. In order to remove NP, a series of MIL-100(Fe)/ZnFe2O4/flake-like porous carbon nitride (MIL/ZC) was synthesized through in-situ synthesis at room temperature. High performance of ternary MIL/ZC is used to degrade NP under visible light irradiation. The results show that 30MIL/ZC2 (20 wt.% ZnFe2O4) ternary composite had the best photocatalytic activity (99.84%) when the dosage was 30 mg. Further mechanism analysis shows that the excellent photocatalytic activity of 30MIL/ZC2 could be ascribed to the double charge transfer process between flake-like porous carbon nitride (PCN) and other catalysts in the ternary heterojunction, and the separation of photogenerated electron-hole pairs was more effective. In addition, the 30MIL/ZC2 also showed high stability after five cycles of the photodegradation reaction. Furthermore, the active substance (•O2−) was considered to be the main active substance in the NP degradation process. Based on the research results, the possible photocatalytic reaction mechanism of 30MIL/ZC2 ternary composite was proposed and discussed in detail.

A Three-Dimensional Branched TiO2 Photoanode with an Ultrathin Al2O3 Passivation Layer and a NiOOH Cocatalyst toward Photoelectrochemical Water Oxidation.

Photoelectrochemical (PEC) water splitting provides an alternative strategy for clean and renewable hydrogen production; however, the practical application is severely limited by the low solar conversion. Herein, a novel and simple strategy has been developed to construct a 3D branched TiO2 photoanode with an ultrathin Al2O3 passivation layer and NiOOH cocatalyst. The structure and properties of the as-obtained photoanodes are explored by X-ray diffraction, Mott-Schottky, electrochemical impedance spectroscopy, and open circuit voltage measurements. The as-obtained B-TiO2/Al2O3/NiOOH ternary heterojunction with a high-quality contact interface exhibits improved light absorption ability, an enhanced photocurrent density of 1.42 mA/cm2 at 1.23 VRHE, high conversion efficiency (0.44% at 0.80 VRHE), and excellent stability compared to pristine TiO2 and alone-Al2O3 or NiOOH decorated TiO2 photoanodes. Therefore, this work could offer a new approach to designing and fabricating high-quality contact interfaces between photoelectrodes and various cocatalysts.