Heterostructure Interface Research Articles

Electronic structure of cuprate–nickelate infinite-layer heterostructure

The discovery of superconductivity in Sr/Ca-doped infinite-layer nickelates Nd(La)NiO2 thin films inspired extensive experimental and theoretical research. However, research on the possibilities of enhanced critical temperature by interface heterostructure is still lacking. Due to the similarities of the crystal structure and band structure of infinite-layer nickelate LaNiO2 and cuprate CaCuO2, we investigate the crystal, electronic and magnetic properties of LaNiO2:CaCuO2 heterostructure using density functional theory and dynamical mean-field theory. Our theoretical results demonstrate that, even a very weak inter-layer z-direction bond is formed, an intrinsic charge transfer between Cu-3d x 2–y 2 and Ni-3d x 2–y 2 orbitals is obtained. The weak interlayer hopping between Cu and Ni leaves a parallel band contributed by Ni/Cu-3d x 2–y 2 orbitals near the Fermi energy. Such an infinite-layer heterostructure with negligible interlayer interaction and robust charge transfer opens a new way for interface engineering and nickelate superconductors.

Construction of Ru/WO3 with hetero-interface structure for efficient hydrogen evolution reaction

Water electrolysis is considered as one most promising technique for hydrogen production. The high efficiency electrocatalyst is the key to accelerating the sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline media. In this work, an efficient HER electrocatalyst with hetero-interfacial metal–metal oxide structure was constructed through a redox solid phase reaction (SPR) strategy. During the annealing process under Ar atmosphere, RuO2 and WS2 in RuO2/WS2 precursor were converted to Ru nanoparticles (NPs) and WO3 in situ, where tiny Ru NPs and oxygen vacancies were uniformly distributed onto the newly formed WO3 nanosheets. Different characterization techniques were adopted to confirm the successful formation of Ru/WO3 electrocatalyst (RWOC). The optimized RWOC sample annealed at 400 °C exhibited the low overpotential value of 13 mV at a current density of 10 mA cm−2 and strong durability under the alkaline condition. Density functional theoretical calculations further revealed that the promoted adsorption/desorption rate of reaction intermediates and the accelerated kinetics of HER process were deduced to the synergistic effect between Ru and WO3 in electrocatalyst. This work provides a feasible method to fabricate highly efficient HER electrocatalysts.

Unlocking Deep and Fast Potassium-Ion Storage through Phosphorus Heterostructure.

Potassium-ion battery represents a promising alternative of conventional lithium-ion batteries in sustainable and grid-scale energy storage. Among various anode materials, elemental phosphorus (P) has been actively pursued owing to the ideal natural abundance, theoretical capacity, and electrode potential. However, the sluggish redox kinetics of elemental P has hindered fast and deep potassiation process toward the formation of final potassiation product (K3 P), which leads to inferior reversible capacity and rate performance. Here, it is shown that rational design on black/red P heterostructure can significantly improve K-ion adsorption, injection and immigration, thus for the first time unlocking K3 P as the reversible potassiation product for elemental P anodes. Density functional theory calculations reveal the fast adsorption and diffusion kinetics of K-ion at the heterostructure interface, which delivers a highly reversible specific capacity of 923 mAh g-1 at 0.05 A g-1 , excellent rate capability (335 mAh g-1 at 1 A g-1 ), and cycling performance (83.3% capacity retention at 0.8 A g-1 after 300 cycles). These results can unlock other sluggish and irreversible battery chemistries toward sustainable and high-performing energy storage.

Moiré-Pattern Modulated Electronic Structures of GaSe/HOPG Heterostructure.

Conventional two-dimensional electron gas (2DEG) typically occurs at the interface of semiconductor heterostructures and noble metal surfaces, but it is scarcely observed in individual 2D semiconductors. In this study, few-layer gallium selenide (GaSe) grown on highly ordered pyrolytic graphite (HOPG) is demonstrated using scanning tunneling microscopy and spectroscopy (STM/STS), revealing that the coexistence of quantum well states (QWS) and 2DEG. The QWS are located in the valence bands and exhibit a peak feature, with the number of quantum wells being equal to the number of atomic layers. Meanwhile, the 2DEG is located in the conduction bands and exhibits a standing-wave feature. Additionally, monolayer GaSe/HOPG heterostructures with different stacking angles (0°, 33°, 8°) form distinct moiré patterns that arise from lattice mismatch and angular rotation between adjacent atomic layers in 2D materials, which effectively modulate the electron effective mass, charge redistribution, and band gap of GaSe. Overall, this work reveals a paradigm of band engineering based on layer numbers and moiré patterns that can modulate the electronic properties of 2D materials.

Interface engineering of charge-transfer excitons in 2D lateral heterostructures

The existence of bound charge transfer (CT) excitons at the interface of monolayer lateral heterojunctions has been debated in literature, but contrary to the case of interlayer excitons in vertical heterostructure their observation still has to be confirmed. Here, we present a microscopic study investigating signatures of bound CT excitons in photoluminescence spectra at the interface of hBN-encapsulated lateral MoSe2-WSe2 heterostructures. Based on a fully microscopic and material-specific theory, we reveal the many-particle processes behind the formation of CT excitons and how they can be tuned via interface- and dielectric engineering. For junction widths smaller than the Coulomb-induced Bohr radius we predict the appearance of a low-energy CT exciton. The theoretical prediction is compared with experimental low-temperature photoluminescence measurements showing emission in the bound CT excitons energy range. We show that for hBN-encapsulated heterostructures, CT excitons exhibit small binding energies of just a few tens meV and at the same time large dipole moments, making them promising materials for optoelectronic applications (benefiting from an efficient exciton dissociation and fast dipole-driven exciton propagation). Our joint theory-experiment study presents a significant step towards a microscopic understanding of optical properties of technologically promising 2D lateral heterostructures.

Heterointerface construction for permalloy microparticles through the surface modification of bilayer metallic organic frameworks: Toward microwave absorption enhancement

Reasonable heterointerface modification can effectively regulate and enhance the microwave absorption of electromagnetic materials. The surface of magnetic permalloy (PM) microparticles is modified herein by coating double-layer metal organic frameworks (MOF), which are composed of a 2-methylimidazole cobalt salt (ZIF-67) layer and a 2-methylimidazole zinc salt (ZIF-8) layer. A stable heterointerface structure with cobalt/carbon (Co/C) and zinc/carbon (Zn/C) layers is formed on the surface of PM microparticles after pyrolysis. These particles include two types of composite particles of PM solely encapsulated by ZIF-67 or ZIF-8, PM@ZIF67 and PM@ZIF8, respectively, and two types of composite PM particles with a double-layered MOF outer shell structure obtained by exchanging the coating sequence (PM@ZIF8@ZIF67 and PM@ZIF67@ZIF8). Furthermore, the thermal decomposition temperature has a significant impact on the surface morphology and magnetic properties of the composite particles. After pyrolyzing at 500 °C, the PM@ZIF67@ZIF8 samples exhibit the highest microwave absorption performance among these samples. Specifically, the minimum reflection loss and effective absorption bandwidth of PM@ZIF67@ZIF8 after pyrolyzing at 500 °C can reach −47.3 dB at a matching thickness of 3.8 mm and 5.3 GHz at a matching thickness of 2.5 mm, respectively. A heterointerface with an electrical field orientation is created in the PM@ZIF67@ZIF8 particles, which effectively enhances the interface polarization and dipole polarization. Furthermore, the formation of a three-dimensional carbon network after pyrolysis is also useful for optimizing impedance matching and enhancing magneto-electric synergism.

On the surface oxidation and band alignment of ferroelectric Sc0.18Al0.82N/GaN heterostructures

Ferroelectric scandium aluminum nitride (ScAlN), owing to its unique properties and seamless integration with the mainstream GaN technology, has attracted considerable attention as one of the most promising materials for next-generation multifunctional electronics. To date, however, a detailed understanding of the fundamental surface properties and the band alignment of ScAlN/III-nitride heterostructure has remained elusive. In this work, with the use of high-resolution X-ray photoelectron spectroscopy measurements, we demonstrate the existence of a considerable oxidation layer on ScAlN when it is exposed to air, which shows a significant impact on the material characterization and electronic structure evaluation. By excluding the possible impact from the surface oxide layer, the band alignment of Sc0.18Al0.82N/GaN can be correctly determined. Simulation results further showed that the Sc0.18Al0.82N barrier layer could offer excellent charge carrier confinement and a high density of two-dimensional electron gas (2DEG) at the heterostructure interface, which is needed for GaN-based high electron mobility transistors (HEMTs) with enhanced performance. This work not only identifies the band alignment between Sc0.18Al0.82N and GaN for future novel ScAlN/III-nitride device applications but also highlights the importance of considering the prevalent surface oxidation issue in the emerging ferroelectric nitride family.

In Situ Formed Heterostructure Interface and Well-Tuned Electronic Structure Ensuring Long Cycle Stability for 4.9 V High-Voltage Li-Rich Layered Oxide Cathodes

High-voltage lithium-rich manganese-based layered oxides (LMLOs) are considered as the most competitive cathode materials for next-generation high-energy-density lithium-ion batteries (LIBs). However, LMLOs still suffer from irreversible lattice oxygen release, uncontrollable interface side reactions, and surface structural degradation. Herein, we propose an integration strategy combining La/Al codoping and LixCoPO4 nanocoating to improve the electrochemical performance of LMLOs comprehensively. La/Al codoping regulates the electronic structure to enhance the redox activity of anions and cations and inhibit structural degradation. The LixCoPO4 nanocoating formed by in situ reaction with the surface residual lithium can not only promote Li-ion migration but also reduce interfacial side reactions. The induced Layered@Rocksalt@LixCoPO4 heterostructure suppresses lattice volume variation and structural degradation during cycling. Under the synergistic effect of the heterostructure interface and well-tuned electronic structure, the capacity retention rate of comodified LMLO materials reaches 80.06% after 500 cycles (2.0-4.65 V) and 75.1% after 340 cycles at 1C under a high cut-off voltage of 4.9 V.

Heterointerface engineering regulating the energy-level configuration of α-MnO2/δ-MnO2 for enhancing toluene catalytic combustion performance

This work offers a novel approach to prepare manganese oxides with heterointerface structure as a superior catalyst for the catalytic combustion of Volatile Organic Compounds (VOCs). The α-MnO2/δ-MnO2 with heterointerfaces were prepared via annealing δ-MnO2 precursors which were obtained from the redox precipitation between HCl and KMnO4. The characterization results indicate that the heterointerface structure of α-MnO2/δ-MnO2 optimizes energy level structure and provides abundant surface defects, showing superior low-temperature reducibility and preferable mobility of oxygen species. Such features significantly enhance the catalytic activity of the α-MnO2/δ-MnO2 with heterointerfaces catalysts for the complete oxidation of toluene (the toluene conversion rates of 10 % and 90 % are 191 °C and 213 °C, respectively). Moreover, the catalysts show high stability for 50 h. The presented catalysts disclose an avenue to address current obstacles in the catalytic oxidation of VOCs.

Far-Red Interlayer Excitons of Perovskite/Quantum-Dot Heterostructures.

Interlayer excitons (IXs) at the interface of heterostructures (HSs) with a staggered band alignment are fascinating quantum quasi-particles with light-emitting and long-lifetime characteristics. In this study, the energy band alignments (EBAs) of the HS of MAPbI3 perovskite thin sheets with CdSe-ZnS core-shell quantum dot (QD) layers are modulated by using different diameters of the QDs. Far-red IX emission is observed at 1.42eV from the HS of MAPbI3 /CdSe-ZnS-QD (λem =645nm) with type-II EBA owing to charge transfer. The lifetime of the far-red IXs is estimated to be 5.68µs, which is considerably longer than that (0.715ns) of the intralayer excitons from CdSe-ZnS-QD. With increasing incident excitation power, the PL peak and its intensity of IXs are blue-shifted and linearly increased, respectively, indicating a strong dipole alignment of far-red IXs at the heterojunction. Back focal plane imaging suggests that the directions of dipole moments of the IXs are relatively out-of-plane compared to those of the intralayer excitons (MAPbI3 and CdSe-ZnS-QD). Notably, the abnormal behavior of the optical characteristics is observed near the phase transition temperature (90K) of MAPbI3 . MAPbI3 /CdSe-ZnS-QD HS photodetectors show the increase in photocurrent and detectivity compared to MAPbI3 at IX excitation.

Electrochemical Self-Healing Nanocrystal Electrodes for Ultrastable Potassium-Ion Storage.

The unique properties of self-healing materials hold great potential in battery systems, which can exhibit excellent deformability and return to its original shape after cycling. Herein, a Cu3 BiS3 anode material with self-healing mechanisms is proposed for use in ultrastable potassium-ion battery (PIB) and potassium-ion hybrid capacitor (PIHC). Different from the binder design, Cu3 BiS3 anode can exhibit the dual advantages of phase and morphological reversibility, further remaining original property after potassiation/depotassiation and exhibiting ultrastable cycling performance. The reversible electrochemical reconstruction during the continuous charge/discharge processes is beneficial to maintain the structure and function of the material. Furthermore, the conversion reactions during the charge and discharge process produce two advantages: i) suppressing the shuttle effect due to the formation of the heterostructure interface between Cu (111) and Bi (012); ii) Cu can avoid the agglomeration of Bi nanoparticles (NPs), further improving the electrochemical performance and long-cycle stability of the Cu3 BiS3 electrode. As a result, the Cu3 BiS3 electrode not only exhibits a long cycle life in half cells, but also 2000 cycles and 12000 cycles in PIB and PIHC full cells, respectively.

Photo-Fenton system Fe3O4/NiCu2S4 QDs towards bromoxynil and cefixime degradation: A realistic approach

The contamination of natural water bodies with toxic pollutants are alarmingly increasing in recent decades. The development of advanced wastewater treatment techniques and their utilization is sought for the effective removal of pollutants especially pharmaceutical and pesticide compounds (PPCs). The present study focused on the green synthesis of a novel heterojunction NiCu2S4 QDs@Fe3O4 nanocomposite (NCs) using Dunica erecta plant extract for the photo-Fenton catalytic degradation of bromoxynil (BRX) and cefixime (CEF). The morphological, structural, and physiochemical properties of the fabricated nanomaterial were analysed via SEM, TEM, XRD, FTIR, Raman, UV–Vis DRS, BET, PL, EIS, and ESR spectroscopy techniques. The NiCu2S4 QDs@30% Fe3O4 showed 97.5 and 81% degradation of BRX and CEF within 200 and 180 min of visible light irradiation, respectively. The excellent photocatalytic efficiency of NCs was attributed to high visible light harvesting ability, efficient charge carriers’ separation, and migration across the heterostructure interface. Various initial parameters including nanomaterial dosage, pollutant concentration, pH, and ions were optimized. A possible photodegradation pathway was predicted based on the intermediates identified from GC-MS/MS analysis, and their non-toxic nature on daphnia, green algae, and fishes was determined by the ECOSAR program. The fabricated NiCu2S4 QDs@Fe3O4 NCs have shown excellent reusability efficiency of 98.7%. The reusability and structural stability were confirmed by six-cycle experiments, XRD, and XPS analysis. In addition, the photocatalyst exhibited 99% of degradation of industrial effluent. The prepared NiCu2S4 QDs@Fe3O4 NCs with superior photocatalytic performance can be used as a promising photocatalyst for the treatment of industrial effluents.

Bean pod-like hollow Zn2SnO4/SnO2 heterostructures in N-doped carbon nanofibers as anode material for high performance lithium storage

Tin-based composites have been extensively investigated as a potential anode for high performance lithium-ion batteries (LIBs) up until this point. However, because of extreme volume expansion and crystal crushing, the researchers have consistently experienced a loss in capacity during lithiation and alloying. To buffer the volume change and achieve superior rate capability, the hollow cube-shaped Zn2SnO4/SnO2 which is wrapped with one-dimensional N-doped carbon nanofibers (CNFs) is prepared. The composites display a delicate bean pod-like heterointerface structure, in which the built-in electric field between Zn2SnO4 and SnO2 can help to speed up the transportation of Li-ions during lithiation and delithiation processes. Additionally, the abundant Zn2SnO4/SnO2 heterointerfaces expose more active sites and make it easier for electrolyte and Li-ion to penetrate. And the N-doped carbon skeleton outside of the Zn2SnO4/SnO2 can help to keep the structural integrity and suppress volume expansion during cycling. As expected, the as-prepared samples exhibit excellent rate performance and a very high ultimate discharge capacity of 765.9 mA h g−1 after 500 cycles at current density of 1.0 A g−1. Furthermore, a full-cell with a prelithiated Zn2SnO4/SnO2 @CNFs-600 anode and a LiFePO4 cathode also displays superior rate and cycling performance. This work highlights the significance of chemical heterointerface engineering in the design of high-performance electrodes for LIBs.

Construction of Co3O4 porous rod/graphene heterostructures toward strong and broadband microwave absorption applications

Microwave absorbing materials (MAMs) are of paramount importance to address electromagnetic radiation pollution concerns. However, the development of MAMs with strong absorption, broadband and good impedance matching features still faces challenges. Herein, a compositional and structural engineering strategy is proposed to tailor the polarization and multiple reflection and scattering characteristics, and the Co3O4 porous rod/graphene (Co3O4 PR/G) heterostructures are constructed. The porous rod structure of Co3O4 and plentiful heterointerfaces between Co3O4 and graphene generate massive microwave attenuation paths and promote the interfacial polarization, resulting in improved microwave attenuation. The Co3O4 PR/G heterostructures exhibit the minimum reflection loss of −49.1 dB and effective absorption bandwidth of 9.3 GHz, overpowering many similar reported microwave absorbers. This work is a new attempt for the development of advanced MAMs with strong absorption and broad bandwidth characteristics, which provides an effective compositional-structural regulating strategy to promote microwave absorption.

The effect of defects for the ion transport of Li3ScCl6 and Li3InCl6 with the interface of lithium metal anode: A first-principles study

Li3ScCl6 and Li3InCl6 have good ionic conductivity and a wide stable chemical window, which showing great potential in many inorganic solid-state electrolytes. Due to the disordered occupancy phenomenon of the lattice sites between the framework lithium ions and the transported ions. The concentration nonuniformity of lithium ions causes the blocking of mobile ions in the transition metal lithium halide solid electrolyte. However, vacancy defects can cause changes in the charge balance of nonstoichiometric systems, which reducing blocking effects during ion diffusion. In addition, lithium dendrites still exist at the interface between the inorganic solid electrolyte and the lithium metal anode. It can effectively improve the occurrence of interface side reaction because LiF has high interface energy. The effect of vacancy defects for lithium ion migration parameters of Li3ScCl6 and Li3InCl6 at different temperatures are simulated by the first principle. The results showing that lithium ions had better migration and diffusion ability in the structure containing lithium site defects of Li3InCl6. A dual-halide electrolyte interface model was constructed to suppress the growth of Li dendrites on the surface of a Li metal anode. The Li3ScCl6-LiF heterostructure interface can stably control ion transport on the surface of a lithium metal anode.

Tunable Schottky barrier in a graphene/AlP van der Waals heterostructure

The controllable modulation of the electronic properties of two-dimensional van der Waals (vdW) heterostructures is crucial for their applications in the future nanoelectronic and optoelectronic devices. In this paper, the electronic properties of a graphene/AlP heterostructure are theoretically studied by first-principles calculation. The results show that due to the weak vdW interaction between graphene and the AlP monolayer, both the Dirac semi-metallic properties of graphene and the semiconductivity properties of monolayer AlP are well retained. The graphene/AlP heterostructure forms a 0.41 eV p-type Schottky contact, and the barrier height and contact type can be successively controlled by the applied external electric field and vertical stress. When the applied electric field exceeds −0.5 V Å−1, the heterostructure interface changes from a p-type Schottky contact to an n-type Schottky contact. When the applied electric field exceeds 0.4 V Å−1 or the interlayer spacing is less than 3.1 Å, the interface contact type changes to Ohmic contact. These results indicate that the graphene/AlP heterostucture behaves as tunable Schottky barrier for potential applications in nano-devices.

Insight into Hot Carrier Kinetics of CsPbBr3/ZnO Heterostructures for Photodetector Application

Understanding the hot carrier kinetics in heterostructures of inorganic halide perovskite nanocrystals (PNCs) and extraction of the excess energy of hot-carriers is crucial for their future emergence in optoelectronic devices. Herein, CsPbBr3/ZnO heterostructures have been prepared via the most adopted in situ hot-injection method, and ZnO nanoparticles were obtained by a simple chemical process. We have investigated the carrier transfer dynamics through steady-state and ultrafast optical measurements. Steady-state measurements (i.e., photoluminescence and time-resolved photoluminescence decay) reveal that electron transfer from PNCs to surface-attached ZnO nanoparticles is the most probable transition process that happened in heterostructured systems. Furthermore, deep insights into the charge transfer kinetics were investigated by performing ultrafast transient absorption (UTA) spectroscopy at two varying pump fluences (i.e., 0.40 and 0.20 mW) with an excitation wavelength of 450 nm. UTA analysis reveals a significant slow hot carrier cooling at 0.40 mW fluence (from 670 fs to 1.56 ps) and 0.20 mW (from 480 fs to 1.23 ps) in CsPbBr3/ZnO heterostructure systems, suggesting reduced exciton recombination and high charge-carrier transfer through the heterostructure interface. The efficient charge extraction in CsPbBr3/ZnO results in a measurable change in photodetector responsivity and detectivity. This study provides an understanding of the hot carrier kinetics of metal halide perovskites CsPbBr3/ZnO for optoelectronic device applications.

Synergistic Transition-Metal Selenide Heterostructure as a High-Performance Cathode for Rechargeable Aluminum Batteries.

We synthesize and characterize a rechargeable aluminum battery cathode material composed of heterostructured Co3Se4/ZnSe embedded in a hollow carbon matrix. This heterostructure is synthesized from a metal-organic framework composite, in which ZIF-8 is grown on the surface of ZIF-67 cube. Both experimental and theoretical studies indicate that the internal electric field across the heterostructure interface between Co3Se4 and ZnSe promotes the fast transport of electron and Al-ion diffusion. As a result, the heterostructured Co3Se4/ZnSe demonstrates superior specific capacity and cycle stability compared to the single-phase Co3Se4 and ZnSe cathode materials.

Engineering Cu1.96S/Co9S8 with sulfur vacancy and heterostructure as an efficient bifunctional electrocatalyst for water splitting

Defect and interface engineering have been recognized as efficient strategies for developing high-performance electrocatalysts. However, it is still challenging to couple defect and interface engineering in transition metal sulfides and understand their dynamic evolution process during electrocatalysis. Herein, we developed one-step pyrolysis of bimetallic sulfide to construct S vacancy-rich Cu1.96S/Co9S8 heterostructure by controlling the critical decomposition temperature. The as-synthesized Cu1.96S/Co9S8 exhibits excellent bifunctional electrocatalytic performance, with a low overpotential of 99 and 200 mV at 10 mA cm−2 towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1.0 mol/L KOH electrolyte, respectively. A symmetric two-electrode cell with Cu1.96S/Co9S8 delivered a current density of 10 mA cm−2 at a low voltage of 1.43 V and showed long-term stability for 200 h. A series of in/ex-situ techniques revealed that the electrochemical reconfiguration only appeared in the OER process, resulting in the CoOOH/CuO and SO42− species promoting OER performance. Meanwhile, the S vacancy and heterostructure interface in Cu1.96S/Co9S8 were proved to optimize the electronic structure and the adsorption of intermediates for HER by density function theory (DFT) simulations. This work provides a promising strategy to construct metal sulfides with rich defects and heterogeneous interfaces and understand their dynamic evolution process for electrochemical storage and conversion devices.

Heterostructure charge transfer dynamics on self-assembled ZnO on electronically different single-walled carbon nanotubes

The charge transfer kinetics of the catalyst particles play a key role in advanced oxidation processes (AOP) for the complete destruction of recalcitrant and persistent contaminants in water. Here, a significant improvement in the photocatalytic performance is observed in the Single-Walled Carbon Nanotube (SWCNT)-ZnO heterostructure photocatalyst. The charge transfer dynamics and factors affecting AOP are studied using ZnO nanoparticles self-assembled onto three electronically different SWCNTs (metallic, semiconducting, and pristine) via the precipitation method, introducing a heterojunction interface. The creation of the SWCNT/ZnO heterostructure interface improves charge transfer and separation, resulting in a charge carrier lifetime of 7.37 ns. Also, surface area, pore size, and pore volumes are increased by 4.2 times compared to those of ZnO. The nanoparticles-coated face-mask fabric used as the floating photocatalyst exhibited high stability and recyclability with 99% RhB degradation efficiency under natural sunlight and 94% under UV light after the 5th cycle. The surface and crystal defects-oxygen or zinc defects/interstitials open new reaction active sites that assist in charge carrier transfer and act as pollutant absorption and interaction sites for enhanced performance. The ideal band edge positions of the valence band and conduction band favor the generation of H2O/OH•, OH·/OH, and O2/HO2• reactive oxygen species. OH• radicals are found to play a vital role in this AOP by using ethanol as an OH• scavenger.