Electron-hole Pairs Research Articles

Plasmonic Graphene-Gold Nanostar Heterojunction for Red-Light Photoelectrochemical Immunosensing of C-Reactive Protein.

The development of red-light photoelectrochemical (PEC) nanoimmunosensors offers new avenues for detecting clinically relevant biomarkers with high sensitivity and specificity. Herein, the first PEC nanoimmunosensor based on a plasmonic graphene and gold nanostar (AuNS) heterojunction excited with 765 nm red light is presented for label-free detection of C-reactive protein (CRP), a key biomarker of inflammation. This platform leverages the unique localized surface plasmon resonance effect of AuNSs in combination with in situ generated graphene to enhance photoelectrical conversion efficiency under 765 nm monochromatic light. This wavelength minimizes photodamage and interference from biological samples. By optimizing the nanoarchitecture and utilizing a bifunctional photoactive transduction platform, a linear detection range of 25-800 pg/mL is achieved, with a limit of detection as low as 13.3 pg/mL. The low-energy red-light activation, effective electron-hole pair separation, and signal amplification allow CRP's rapid, selective, and sensitive detection in real clinical samples from patients with low-grade chronic inflammation. The nanoimmunosensor demonstrated consistent analytical performance across multiple samples, showing potential for accurate biomarker monitoring in inflammatory disorders. This work highlights plasmonic nanomaterials to develop robust PEC immunosensors that provide scalable, noninvasive, automated, low-background noise as a highly sensitive alternative for clinical diagnostics.

Enhanced Photocatalytic Hydrogen Generation from Methanol Solutions via In Situ Ni/Pt Co-Deposition on TiO2

TiO2 is widely utilized as an excellent photocatalyst in energy production. However, its rapid electron and hole recombination confers poor photocatalytic activity. Cocatalysts are essential for increasing photocatalytic efficacy by introducing improved electron transmission and enlarging the active site. Herein, the photocatalytic degradation of aqueous methanol solution to generate hydrogen was studied with the simultaneous in situ deposition of metals (M = Ag, Cu, Ni, Pd, and Pt) on the TiO2 surface. Adding methanol to water and incorporating a bimetallic cocatalyst enhanced hydrogen production by reducing the electron–hole pair recombination. The studied metal ions could be reduced by the conduction band electrons of TiO2 for the in situ simultaneous deposition of metal. The larger work function value of the studied metals favored the Schottky junction formation, which contributed to increasing photocatalytic efficiency. Among these simultaneous metal-deposited photocatalysts, maximal photocatalytic hydrogen production was achieved with NiPt/TiO2. The optimal component was 0.01 wt.% Ni/1.0 wt.% Pt for TiO2. The hydrogen evolution with NiPt/TiO2 was approximately 341 and 1.3 times better than that with pure TiO2 and Pt/TiO2, respectively. A potential reaction pathway for photocatalytic hydrogen production from an aqueous methanol solution over NiPt/TiO2 photocatalyst has also been proposed.

Rapid photocatalytic degradation of selective organic dyes using metal oxide-metal sulphide and its inverted nanocomposites

The chemical precipitation approach was employed to synthesize novel heterostructures, namely CeO2-ZnS and SnO2-ZnS, along with inverted nanocomposites ZnS-CeO2 and ZnS-SnO2. The nanocomposites were subjected to characterization using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis absorption spectra, and photoluminescence spectra. The TEM images demonstrated particles that were homogeneous, well-dispersed, and comparatively tiny with a sphere-like structure. This indicates successful synthesis and desirable morphological properties of the nanocomposites. The integration of varied nanoparticles within a heterostructure commonly gives rise to synergistic effects, imparting superior properties to the composite compared to the individual components. These nanocomposites tested for their photocatalytic degradation efficiency using Rose Bengal (RB) and Crystal Violet (CV) dyes under natural sunlight and they exhibited approximately 95 % degradation rate. The degradation results demonstrated a significant enhancement in the photocatalytic efficiency of ZnS-CeO2 and CeO2-ZnS nanocomposites. This improvement was attributed to the effective recombination suppression of photogenerated electron-hole pairs, leading to the generation of highly reactive free radicals. The first-order kinetic rate constant for CeO2-ZnS was determined to be 0.52 min−1 for CV and 0.53 min−1 for RB. The present research work has the potential to offer a novel approach to the construction of new heterojunction photocatalysts and to provide a more profound understanding of the treatment of textile organic dyes.

Visible light-responsive enrofloxacin PEC aptasensor based on CN QDs sensitized Bi4O5Br2 nanosheets.

The excessive application of enrofloxacin (ENR) results in residues contaminating both food and the environment. Consequently, developing robust analytical methods for the selective detection of ENR is crucial. The photoelectrochemical (PEC) sensor has emerged as a highly sensitive analytical technique that has seen rapid development in recent years. The functioning of a PEC sensor relies on the reducing capacity of photogenerated electrons and the oxidizing capacity of photogenerated holes produced by the photoactive material. Bi4O5Br2 demonstrates its potential in electrochemical detection, but faces inherent challenges, including swift electron-hole recombination and slow carrier migration, which hinder its catalytic activity. In this study, we synthesized carbon nitride quantum dots doped with Bi4O5Br2 (CN QDs/Bi4O5Br2) through an in situ growth method, utilizing this composite as a photoactive material. The incorporation of CN QDs leads to a 17-fold increase in photocurrent compared to Bi4O5Br2 alone. This enhancement is attributed not only to the improved separation of electron-hole pairs, facilitated by the CN QDs, which boosts photocatalytic activity, but also to the enlarged range of visible light absorption. We employed an ENR-specific aptamer as the recognition element, resulting in the construction of a high-performance photoelectrochemical aptasensor for ENR detection. The sensor exhibited a linear detection range of 1×10-1 to 1×106ngmL-1 and a detection limit of 0.033ngmL-1. The impressive performance of the CN QDs/Bi4O5Br2 sensing platform demonstrates its potential application in detecting ENR concentrations in food, biomedical contexts, and environmental analyses. Benefiting from the sensitization of CN QDs, CN QDs/Bi4O5Br2 exhibited 17-fold PEC signal of pure Bi4O5Br2. The presence of quantum dots in CN QDs/Bi4O5Br2 facilitates rapid separation of electron-hole pairs, leading to significantly enhanced PEC activity and improved detection performance for ENR. This research convincingly illustrates that integrating CN QDs with Bi4O5Br2 nanosheets could pave the way for designing more efficient bismuth-based semiconductor photoactive materials for sensing applications.

Magnetic field and photon co-enhanced S-scheme MXene/In2S3/CoFe2O4 heterojunction for high-performance lithium-oxygen batteries

Under the spotlight for their potential to reduce over-potential, photo-assisted Li–O2 batteries still face a key challenge: the rapid recombination of photo-generated electron-hole pairs, which limits their efficiency. In this study, we address this limitation by designing a Li–O2 battery that integrates both photo and magnetic field assistance, using an S-scheme MXene/In2S3/CoFe2O4 heterojunction photocathode. This unique combination enhances visible light absorption and generates a strong built-in electric field, facilitating effective charge separation and boosting photocatalytic activity. During discharge, photo-generated electrons participate in the oxygen reduction reaction, while photo-induced holes contribute to the decomposition of discharge products during charging. Furthermore, the introduction of a magnetic field, confirmed through vibrating sample magnetometer, Mössbauer spectroscopy, X-ray absorption near edge structure, and cyclic voltammetry analyses, enhances electron-hole separation via Lorentz forces and spin–orbit coupling, accelerating the formation and decomposition of Li2O2. With this synergistic approach, the battery achieves a high specific capacity of 26500 mAh g−1, ultra-low oxygen reduction/evolution reaction over-potentials of 0.08 V/0.17 V, and a long cycle life of 2000 cycles with energy efficiency of 98.11 %. This work demonstrates the promising potential of combining photo and magnetic field effects to improve the electrochemical performance of Li–O2 batteries, opening new avenues for high-performance energy storage systems.

Effective removal of carbofuran pesticide in wastewater using silver-doped TiO2 photocatalyst

This study presents effective methods for utilizing the TiO2 photocatalyst in environmental remediation, with a particular focus on the removal of the carbofuran pesticide (CBFP) from wastewater. Silver (Ag) was selected as a potential dopant to improve the optical properties as well as the electron-hole pair separation efficiency of TiO2. Ag-doped TiO2 (Ag-TiO2) effectively decomposed 92.8% CBFP under solar light, which was significantly higher than that of TiO2 (21.3%). Ag-TiO2 also exhibited good reusability for CBFP degradation, with a reduction in removal efficiency of less than 3% after three cycles. In practical applications, Ag-TiO2 successfully degraded 89.3% of CBFP in wastewater and 98.7% in surface water. The findings of this work bring an effective method for removing pesticide pollutants using Ag-TiO2 photocatalyst.

Low-dimensional Hetero-interlayer Enabling Sub-bandgap Photovoltaic Conversion for Perovskite Solar Cells.

Actualizing sub-bandgap photovoltaic conversion is effective in remitting energy loss and pushing theoretical efficiency limits for perovskite solar cells (PSCs). Herein, a zero-dimensional organic metal halide based on hydroxyquinoline (HQ) is developed to sensitize PSCs for near-infrared region gain to implement sub-bandgap photovoltaic conversion for enhancing power-conversion-efficiency (PCE) of PSCs. [ZnI4]2- skeletons containing heavy atoms intensify the direct singlet-to-triplet state transition of organic chromophores HQ, Meanwhile, the triplet energy of HQ is close to resonance with perovskite bandgap, favoring the energy transfer to perovskite and exciting the additional electron-hole pairs, which was observed by transient absorption spectroscopy, confirming the sensitization of perovskite to increase sub-bandgap photocurrent. HQ2ZnI4 modifies electronic and crystal structure, optimizes energy-level arrangement, and acts as a protective layer, realizing considerable PCEs in small (6.25 mm2)-/larger-area (1 cm2) devices and excellent operational stability. This low-cost strategy brings vitality to the light management of PSCs and expands low-dimensional materials.

(ZnO)12 Cluster Decorated 2D Porous CN Materials as Efficient Solar Cells.

Developing high-performance solar cells is a practical way to improve clean energy conversion efficiency. However, the performance of solar cells faces challenges such as fast carrier combination, poor stability, and limited solar light harvesting. Herein, we propose a strategy by decorating periodic holes in two-dimensional (2D) porous carbon-nitrogen (CN) materials with a zero-dimensional (0D) semiconducting (ZnO)12 cluster. The effects of different CN substrates on the photogenerated carrier dynamics and solar cell performance are revealed by first-principles calculations combined with time-dependent ab initio nonadiabatic molecular dynamic (NAMD) simulations. With high structural stabilities, proper energy gaps of 1.81-3.23 eV, and positions, (ZnO)12/CN heterostructures possess enhanced light absorption in the visible region, excellent separation of photogenerated electron-hole pairs with carrier relaxation times of 140-773 ns for electrons and 82-128 ns for holes, and large short-circuit current densities of 15-34 mA cm-1. The study unveils the fundamental principles for optimizing the solar cell efficiency of metal oxide cluster decorated CN materials in energy conversion.

Large exciton binding energy in a bulk van der Waals magnet from quasi-1D electronic localization

Excitons, bound electron-hole pairs, influence the optical properties in strongly interacting solid-state systems and are typically most stable and pronounced in monolayer materials. Bulk systems with large exciton binding energies, on the other hand, are rare and the mechanisms driving their stability are still relatively unexplored. Here, we report an exceptionally large exciton binding energy in single crystals of the bulk van der Waals antiferromagnet CrSBr. Utilizing state-of-the-art angle-resolved photoemission spectroscopy and self-consistent ab-initio GW calculations, we present direct spectroscopic evidence supporting electronic localization and weak dielectric screening as mechanisms contributing to the amplified exciton binding energy. Furthermore, we report that surface doping enables broad tunability of the band gap offering promise for engineering of the optical and electronic properties. Our results indicate that CrSBr is a promising material for the study of the role of anisotropy in strongly interacting bulk systems and for the development of exciton-based optoelectronics.

Achieving Near Infrared Photodegradation by the Synergistic Effect of Z-Scheme Heterojunction and Antenna of Rare Earth Single Atoms.

Near-infrared light response catalysts have received great attention in renewable solar energy conversion, energy production, and environmental purification. Here, near-infrared photodegradation is successfully achieved in rare earth single atom anchored NaYF4@g-C3N4 heterojunctions by the synergistic effect of Z-scheme heterojunction and antenna of rare earth single atoms. The UV-vis light emitted by Tm3+ can not only be directly absorbed by g-C3N4 to generate electron-hole pairs, realizing efficient energy transfer, but also be absorbed by NaYF4 substrate, and generating photo-generated electrons at its impurity level, transferring the active charge to the valence band of g-C3N4, forming a Z-scheme heterojunction and further improving the photocatalytic efficiency. Importantly, Tm single atoms has multiple functions such as acting as charge transfer channels to facilitate charge transfer, regulating the critical distance of energy transfer, and prolonging electron-hole pair lifetime. Under NIR light, it exhibited remarkable performance in degrading antibiotics (the removal rate of TC reached 91% for 6 h) while maintaining excellent stability. The LC-MS/MS technology is used to reveal the reaction intermediates, active species, and reaction pathways, and the complex mechanism of photodegradation is further proposed. This study provides experimental and theoretical support for designing and synthesizing catalysts with near-infrared light response characteristics.

Colloidal Design and Preparation of an Internal Electric Modulated Z-Scheme BiOI-CdS Heteronanostructure with Oxygen-Rich Vacancies.

Photoelectrochemical (PEC) water splitting offers an ideal strategy for the development of clean and renewable energy. However, its practical implementation is often inhibited by the high recombination rate of photogenerated charge carriers and the instability of photoanodes. Introducing defect engineering (such as oxygen vacancies) and constructing internal electric field-modulated Z-scheme heteronanostructures (HNs) can be considered as effective approaches to overcome these obstacles. Herein, a flexible method is developed for synthesizing Z-scheme BiOI-CdS HNs with oxygen vacancies, which induce an internal electric field between ultrathin BiOI nanosheets and a CdS semiconductor. This Z-scheme mechanism significantly promotes the separation of photogenerated electron-hole pairs, thereby enhancing the PEC performance. The BiOI-CdS photoanode achieves a photocurrent density of 4.22 mA cm-2 at 1.6 V vs RHE under AM 1.5G illumination (100 mW cm-2), outperforming bare BiOI and CdS. Moreover, the photoanode exhibits exceptional stability with only a slight decrease of approximately in its initial photocurrent after a rigorous 4 h test, surpassing other counterparts in terms of durability. This work affords a better understanding of oxygen vacancies and the construction of highly efficient and stable Z-scheme photoanodes for feasible PEC application.

Fabrication of Polydopamine/hemin/TiO2 Composites with Enhanced Visible Light Absorption for Efficient Photocatalytic Degradation of Methylene Blue

With the rapid progression of industrialization, water pollution has emerged as an increasingly critical issue, especially due to the release of organic dyes such as methylene blue (MB), which poses serious threats to both the environment and human health. Developing efficient photocatalysts to effectively degrade these pollutants is therefore of paramount importance. In this work, titanium dioxide (TiO2) was modified with the photosensitizer hemin and the hydroxyl-rich polymer polydopamine (PDA) to enhance its photocatalytic degradation performance. Hemin and PDA function as photosensitizers, extending the light absorption of TiO2 into the visible spectrum, reducing its bandgap energy, and effectively promoting separation of photogenerated electron–hole pairs through conjugated structures. Additionally, the strong adhesion of PDA enabled the rapid transfer and effective utilization of photogenerated electrons, while its abundant phenolic hydroxyls increased MB adsorption on the photocatalyst’s surface. Experimental results demonstrated a significant enhancement in photocatalytic activity, with the 1%PDA/3%hemin/TiO2 composite achieving degradation rates of 91.79% under UV light and 71.53% under visible light within 120 min, representing 2.22- and 2.05-fold increases compared to unmodified TiO2, respectively. This research presents an effective modification approach and provides important guidance for designing high-performance TiO2-based photocatalysts aimed at environmental remediation.

Bi4Ti3O12-V/Ag Composite with Oxygen Vacancies and Schottky Barrier with Photothermal Effect for Boosting Nizatidine Degradation

Piezo-photocatalysis is a promising solution to address both water pollution and the energy crisis. However, the recombination of electron–hole pairs often leads to poor performance, rendering current piezoelectric photocatalysts unsuitable for industrial water treatment. To overcome this issue, oxygen vacancies (V) and Ag nanoparticles (NPs) are introduced into Bi4Ti3O12 (BTO) nanosheets, forming Schottky junctions (BTO-V/Ag). These 2D/3D structures offer more exposed active sites, shorter carrier separation distances, and improved piezo-photocatalytic performance. Additionally, the photothermal effect of Ag NPs supplies additional energy to counteract adsorption changes caused by active species, promoting the generation of more active species. The rate constant of the optimized BTO-V/Ag-2 in the piezo-photocatalytic degradation of nizatidine (NZTD) was 4.62 × 10−2 min−1 (with a removal rate of 98.34%), which was 4.32 times that of the initial BTO. Moreover, the composite catalyst also showed good temperature and pH response. This study offers new insights into the regulatory mechanisms of piezo-photocatalysis at the Schottky junction.

Theoretical Design for Thorium-Containing Two-Dimensional Materials.

Actinide elements are characterized by their unique electronic correlations, variable valence states, and localized 5f electrons, leading to unconventional electronic and topological properties in their compounds. The distinctive physical properties of actinide materials are maintained in low-dimensional forms, yet two-dimensional (2D) actinide materials remain largely unexplored due to their scarcity and the experimental challenges posed by their radioactivity. To fill the knowledge gap in 2D actinide materials, we theoretically designed a series of stable thorium-containing 2D materials, including MXenes, chalcogenides, halides, and other compounds with unique structures. These novel thorium-containing 2D materials show excellent thermodynamic, mechanical, and dynamical stability. Their electronic structures and potential applications were investigated. Considering the proper band edge positions, strong visible light absorption, and effective separation of photogenerated electron-hole pairs, ThPSe3 is proposed as a promising photocatalyst for water splitting. Our work significantly expands the 2D actinide materials family, and further opens new avenues for their experimental realization and applications.

TiO2/CoOx heterostructure decorated MIL-100(Fe) by atomic layer deposition for enhanced photocatalytic oxygen production.

Efficient separation of photogenerated charge carriers is essential for maximizing the photocatalytic efficiency of semiconductor materials in oxygen evolution reactions (OER). This study presents a novel trimetallic photocatalyst, MIL-100(Fe)/TiO2/CoOx, synthesized through a facile microwave-assisted hydrothermal method followed by atomic layer deposition (ALD). The porous MIL-100(Fe) serves as a support for the sequential deposition of TiO2 and CoOx layers via ALD, which enhances electron-hole pair separation and minimizes their recombination. Characterization using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) confirms the uniform deposition of TiO2 and CoOx layers on the MIL-100(Fe) surface. The optimized photocatalyst, processed with 20 deposition cycles of Co, exhibits exceptional photocatalytic OER performance, with an oxygen evolution rate of 558.3 μmol g-1 h-1. This enhancement in activity is attributed to the synergistic interaction between the spatially separated TiO2 and CoOx cocatalysts, which facilitates efficient charge transfer and increases the number of active sites. These findings highlight the potential of ALD-fabricated heterostructures in the development of advanced photocatalysts for sustainable energy production.

Enhancing the Photocatalytic Efficacy of g-C3N4 Through Irradiation Modification and Composite Construction with Ti3C2 for Photodynamic Therapy

Photodynamic therapy (PDT) holds considerable promise for advancing anticancer treatment, owing to its precision and minimally invasive nature. In this study, we successfully synthesized a series of titanium carbide (Ti3C2, TC)/graphitic carbon nitride (g-C3N4, CN) nanocomposite through a synergistic approach combining electron beam irradiation and 2D/2D composite formation. According to the results, 1TC/200-CN (1TC, which TC was 1, referred to the mass ratio; 200-CN, which CN was 200 kGy, referred to the irradiation metering) displayed a 94% degradation rate of methylene blue (10 mg/L) in 100 min. Furthermore, the proliferation rate of CAL-27 cells was suppressed to just 23.3% at a concentration of 320 μg/mL of 1TC/200-CN. Notably, the group treated with this concentration exhibited the largest residual scratch area, accompanied by a notable decrease in mitochondrial membrane potential. These enhanced effects were attributed to the efficient transfer of electron-hole pairs facilitated by the TC/CN composite. Our findings not only contribute to the development of efficient and stable nanocomposites for PDT applications but also provide valuable insights into the utilization of nanomaterials in the biomedical field, thereby paving the way for potential breakthroughs in cancer treatment.

A highly sensitive photoelectrochemical sensor for the detection of theophylline based on the photoelectrocatalytic activity of a nanocomposite of polydopamine nanospheres and gold nanoparticles.

A label-free photoelectrochemical (PEC) sensor for detecting theophylline (TP) was exploited based on electrodes modified with a nanocomposite of polydopamine nanospheres (PDSs) and gold nanoparticles (AuNPs). PDS particles were prepared by oxidative autopolymerization, and their reducibility was utilized in one step to reduce the gold nanoparticles in situ. The AuNPs-PDS/ZnS PEC sensor was constructed by electrochemical deposition and drop coating. The detection medium employed was TP in 0.1 M phosphate buffered saline (PBS, pH 7.00). The proposed PEC sensor demonstrated exceptional photoelectric catalytic capability with respect to TP oxidation. Under light irradiation, electron-hole pairs were generated in ZnS. Electrons from TP oxidation trapped holes and produced an anodic photocurrent. The modification process of electrodes and TP oxidation recognition performance were studied by the I-T method. A linear relationship was observed between the oxidation photocurrent of TP and its concentration over a range of 0.5 to 50 μg mL-1. The detection limit was established at 0.13 μg mL-1 (S/N = 3). This sensor exhibited optimal selectivity, prolonged stability, and commendable reproducibility when determining TP. It was successfully applied to measure TP content in various matrices, including tea, biological samples, and blood samples, with acceptable recovery rates ranging from 95.3% to 107.7%.

Self-Assembly Strategy for Synthesis of WO3@TCN Heterojunction: Efficient for Photocatalytic Degradation and Hydrogen Production via Water Splitting.

Herein, a WO3@TCN photocatalyst was successfully synthesized using a self-assembly method, which demonstrated effectiveness in degrading organic dyestuffs and photocatalytic evolution of H2. The synergistic effect between WO3 and TCN, along with the porous structure of TCN, facilitated the formation of a heterojunction that promoted the absorption of visible light, accelerated the interfacial charge transfer, and inhibited the recombination of photogenerated electron-hole pairs. This led to excellent photocatalytic performance of 3%WO3@TCN in degrading TC and catalyzing H2 evolution from water splitting under visible-light irradiation. After modulation, the optimal 3%WO3@TCN exhibited a maximal degradation rate constant that was twofold higher than that of TCN alone and showed continuous H2 generation in the photocatalytic hydrogen evolution. Mechanistic studies revealed that •O2- constituted the major active species for the photocatalytic degradation of tetracycline. Experimental and DFT results verified the electronic transmission direction of WO3@TCN heterojunction. Overall, this study facilitates the structural design of green TCN-based heterojunction photocatalysts and expands the application of TCN in the diverse photocatalytic processes. Additionally, this study offers valuable insights into strategically employing acid regulation modulation to enhance the performance of carbon nitride-based photocatalysts by altering the topography of WO3@TCN composite material dramatically.

Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe2O3 Photoelectrochemical Water Oxidation Performance

Considering the poor conductivity of Fe2O3 and the weak oxygen evolution reaction associated with it, surface hole accumulation leads to electron hole pair recombination, which inhibits the photoelectrochemical (PEC) performance of the Fe2O3 photoanode. Therefore, the key to improving the PEC water oxidation performance of the Fe2O3 photoanode is to take measures to improve the conductivity of Fe2O3 and accelerate the reaction kinetics of surface oxidation. In this work, the PEC performances of Fe2O3 photoanodes are synergistically improved by combining loaded an FeOOH cocatalyst and oxygen vacancy doping. Firstly, amorphous FeOOH layers are successfully prepared on Fe2O3 nanostructures through simple photoassisted electrodepositon. Then oxygen vacancies are introduced into FeOOH-Fe2O3 through plasma vacuum treatment, which reduces the content of Fe-O (OL) and Fe-OH (-OH), jointly promoting the generation of oxygen vacancies. Oxygen vacancy can increase the concentration of most carriers in Fe2O3 and form photo-induced charge traps, promoting the separation of electron holes and enhancing the conductivity of Fe2O3. The other parts of -OH act as oxygen evolution catalysts to reduce the reaction obstacle of water oxidation and promote the transfer of holes to the electrode/electrolyte interface. The performance of FeOOH-Fe2O3 after plasma vacuum treatment has been greatly improved, and the photocurrent density is about 1.9 times higher than that of the Fe2O3 photoanode. The improvement in the water oxidation performance of PEC is considered to be the synergistic effect of the cocatalyst and oxygen vacancy. All outstanding PEC response characteristics show that the modification of the cocatalyst and oxygen vacancy doping represent a favorable strategy for synergistically improving Fe2O3 photoanode performance.

Defects Calculation and Accelerated Interfacial Charge Transfer in a Photoactive MOF-Based Heterojunction.

Photocatalytic hydrogen production is currently considered a clean and sustainable route to meet the energy and environmental issues. Among, heterojunction photocatalysts have been developed to improve their photocatalytic efficiency. Defect engineering of heterojunction photocatalysts is attractive due to it can perform as electron trap and change the band structure to optimize the interfacial separation rate of photogenerated electron-hole pairs. Here, the MOF-based heterojunction photocatalysts with theoretically high reduction and oxidation abilities are successfully synthesized, denoted ZrO2/Pt/Zr-MOF-X, with tuned linker defectivity through an in situ electrochemical route. The defectivity are rationally calculated from the TG and 1H NMR results. A positive correlation is found between the defectivity and photocatalytic activity, and ZrO2/Pt/Zr-MOF-6 with the optimized defectivity of ca. 35% exhibits the highest hydrogen production rate of up to 2923 µmol g-1 h-1, illustrating the importance of structural defects in heterojunction photocatalysts. Ultrafast transient absorption spectroscopy and electron spin resonance results unveil the highest carrier concentration and charge separation efficiency in the defected heterostructure of ZrO2/Pt/Zr-MOF-6 through a direct Z-scheme contact, leading to its efficient photocatalysis through the high redox power.