Enhanced Charge Separation Research Articles

Phosphate modified nanoarchitectonics for promoted photocatalytic singlet oxygen generation and carbamazepine degradation of (0 1 0) facet-exposed BiOCl

1O2 generation over (001) or (010) facet exposed BiOCl (B001 or B010) with/without phosphate modification were studied from the aspects of excitons involved energy transfer route, the O2− oxidation based charge transfer route and the H2O2 oxidation by HClO. Phosphate modification not only enhance charge separation thus result in H2O2 oxidation by HClO to release 1O2 but also weaken excitonic effect in the confined layer of BiOCl accordingly affect 1O2 generation via energy transfer. Considering [001] orientation favors the formation of excitons than that of [010] direction over BiOCl, excitons loss was hardly compensated by the H2O2 oxidation by HClO for 1O2 generation over phosphate modified B001. Nevertheless, limited excitonic effect makes the O2− oxidation by h+ via charge transfer as dominant route for 1O2 yielding over B010, the extra H2O2 oxidation with HClO after phosphate modification significantly enhance 1O2 generation over B010 followed with 2.2 times higher carbamazepine photodegradation activity. The initial attack of CC bond via 1O2 to form epoxide played important roles on carbamazepine degradation. This study demonstrated that the facet-specific phosphate modification of photocatalysts can finely tune reactive 1O2 species for superior pharmaceuticals degradations.

Enhanced detection of cardiac troponin-I using CdSe/CdS/ZnS core-shell quantum dot/TiO2 heterostructure photoelectrochemical sensor

This paper introduces a photoelectrochemical sensor employing red-emitting CdSe/CdS/ZnS core-shell quantum dot/TiO2 heterostructure for detecting cardiac troponin-I (cTnI) biomarkers. The sensor utilizes a photoactive layer-by-layer self-assembly of CdSe/CdS/ZnS nanocrystals within a TiO2 nanoparticle photon-sensitive layer to enhance charge separation, thereby boosting sensor photocurrent. Additionally, the CdSe/CdS/ZnS quantum dot layer enhances photocurrent stability by facilitating the separation of photo-excited electrons and holes. Functionalization of the CdSe/CdS/ZnS core-shell quantum dot/TiO2 heterostructure-based photoelectrochemical sensor with anti-troponin involves first activating -COOH functionalized CdSe/CdS/ZnS with carbodiimide cross-linkers, followed by cTnI protein capture. Photocurrent changes are measured using amperometry. The sensor format exhibits an enhanced photocurrent signal proportional to concentration, with a detection range of 10 pg/mL to 0.2 ng/mL of cTnI protein. The use of a red-emitting CdSe/CdS/ZnS quantum dot layer ensures chemical stability during and after chemical coupling on the sensor. This study showcases the successful application of CdSe/CdS/ZnS core-shell quantum dot/TiO2 heterostructure-based photoelectrochemical sensors for early detection of troponin-I protein in cardiac disease diagnostics.

Plasmonic molybdenum carbide MXene nanosheets for highly efficient and stable perovskite solar cells

Besides the excellent metallic electrical conductivity, high carrier mobility, and high optical transmittance, the two-dimensional MXenes exhibiting impressive optical and plasmonic properties have been explored to photodiodes. However, their potential use of surface plasmons oscillating in perovskite solar cells has not been studied. Herein, we incorporate, for the first time, Mo2CTx MXene nanosheets with characteristic plasmonic absorption in the whole visible region into the perovskite active layer. First, the presence of Mo2CTx nanosheets in the perovskite film increases the perovskite grain size due to the decreased growth rate and passivation of the defects around the grain boundaries through strong interaction with undercoordinated Pb2+. Furthermore, with the help of the localized surface plasmon resonance effect of Mo2CTx nanosheets, the exciton binding energy in the perovskite absorber is reduced, which suggests the efficient exciton dissociation and enhanced charge separation. Consequently, Mo2CTx nanosheets based perovskite solar cell device exhibits a champion power conversion efficiency (PCE) of 24.05 %. It is worth noting that the unencapsulated devices demonstrate considerably improved stability, maintaining about 89.25 % of the initial PCE after aging in air for 3000 h. This fascinating strategy provides more opportunities of the functional MXene materials for the perovskite optoelectronics.

Cobalt-doped graphitic carbon nitride: A multifunctional material for humidity sensing, electrochemical water splitting and environmental remediation applications

Graphitic carbon nitride (g-C3N4) has emerged as a promising eco-friendly material for catalysis and sensing applications due to their unique properties. However, limitations like low specific surface area, insufficient light absorption, and poor conductivity hinder their broader usability. Elemental doping has been established as an effective approach to modify the electronic structure and bandgap of g-C3N4 thus significantly expanding its light-responsive range for enhanced charge separation. This work reports on the fabrication of cost-effective and stable g-C3N4 and cobalt-doped g-C3N4 (Co@g-C3N4) via a simple one-step calcination process. The humidity sensing performance of both g-C3N4 and Co@g-C3N4 was evaluated across a broad humidity range (7 % - 94 % RH) at various testing frequencies. The results demonstrated good reversibility with Co@g-C3N4 exhibiting superior performance compared to pristine g-C3N4. Furthermore, the synthesized materials were assessed for their suitability as photoelectrochemical water splitting catalysts for hydrogen production, representing a step towards energy-efficient fuel cells. Notably, Co@g-C3N4 displayed enhanced performance with a lower onset potential (420 mV) and a lower Tafel slope (65.4 mV dec-1) for the hydrogen evolution reaction (HER) compared to undoped counterparts. Additionally, Co@g-C3N4 nanorods exhibited remarkable performance for the oxygen evolution reaction (OER), showcasing a lower onset potential (1.505 V) and a considerably low overpotential (270 mV), surpassing numerous reported electrocatalysts and even rivaling precious-metal-based ones. Finally, enhanced photocatalytic activities for organic dyes degradation were recorded for the mentioned materials. Therefore, g-C3N4 and related materials have great potential for their industrial electrochemcial applications.

Plasmon-induced efficient solar-driven H2 production using bimetallic core-shell Cu@Ag:TiO2 nanocomposite photocatalyst

The nano-interface formed by bimetallic Cu@Ag nanoparticles (NPs) on a TiO2 surface enhances charge separation through plasmonic heterojunctions. These bimetallic Cu@Ag NPs were synthesized via the a galvanic replacement reaction (GRR) involving Ag+ in an aqueous medium and metallic Cu NPs on TiO2. During the GRR, Cuδ+ and Agδ+ charge pairs are generated by electron transfer from the catalyst surface. These charge pairs act as active sites, significantly enhancing photocatalytic hydrogen production. Additionally, the cubic crystalline phase of metallic Cu NPs is maintained after the GRR process with Ag ions, while the size of bimetallic Cu@Ag NPs remains constant. Consequently, Cu@Ag NPs supported on TiO2 (Cu@Ag:TiO2) exhibit increased donor charge density of 1.66 × 1020 cm−3 and facilitate rapid charge transfer. As a result, the photocatalytic hydrogen production rate of Cu@Ag:TiO2 is 20 times higher than that of pristine TiO2. Moreover, the visible-light responsive photocatalytic activity of Cu@Ag:TiO2 NPs reaches 3.4 mmol g−1 over 5 hours, which is 78 times higher than that of pristine TiO2. This remarkable enhancement is attributed to the formation of a plasmonic heterojunction with close contact between Cu@Ag and TiO2, enabling efficient charge carrier separation.

Highly dispersed g-C3N4 on one-dimensional W18O49/carbon nanofibers for constructing well-connected S-scheme heterojunctions with synchronous H2 evolution and pollutant degradation performance

Synchronous dual-functional photocatalytic reaction can simultaneously consume photogenerated electrons and holes, leading to redox reaction, which is a promising photocatalytic reaction system model. However, the severe recombination of photogenerated charge carriers in photocatalysts limits their photocatalytic performance. In this work, W18O49/C@g-C3N4 S-scheme heterojunctions nanofibers with core-shell structure were prepared through electrospinning combined with the vapor deposition method, for high-performance synchronous photocatalytic H2 evolution and pollutant degradation. The X-ray photoelectron spectroscopy and Mott-Schottky results demonstrated that the S-scheme heterojunctions effectively separate charges while maintaining high redox capacity. The UV-vis-NIR absorption spectra results revealed the LSPR effect in W18O49, which can generate “hot electrons”. The scanning electron microscope images showed that the unique core-shell structure independently consumes electrons and holes, thereby enhancing charge separation and accelerating carrier kinetics. Specifically, the synchronous H2 evolution and RhB degradation efficiency of W18O49/C@g-C3N4 nanofibers were approximately 5.60 and 3.51 times higher than that of W18O49/C, and 2.45 and 22.55 times higher than that of C@g-C3N4 nanofibers, respectively. Furthermore, the ultra-long one-dimensional network structure of W18O49/C@g-C3N4 nanofibers enables easy recycling after liquid reactions. This study presents a novel approach for customizing band structures and unique surface morphology to improve synchronous dual-functional photocatalytic activity.

Orientation-Dependent Photocatalysis of Imine-Linked Covalent Organic Frameworks Based on Thienothiophenes for Oxidation of Amines to Imines.

Toward visible light photocatalysis, covalent organic frameworks (COFs) have recently garnered growing attention. The effect of different orientations of imine of imine-linked COFs on photocatalysis should be elucidated. Here, two COFs are developed with 2,5-diphenylthieno[3,2-b]thiophene (DPTT) and 1,3,6,8-tetraphenylpyrene (Py) linked by imine, affording DPTT-Py-COF and Py-DPTT-COF, respectively. Distinctly, DPTT-Py-COF and Py-DPTT-COF have high crystallinity and porosity, paving the way to highly efficient photocatalysis. Theoretical calculations demonstrate that both DPTT-Py-COF and Py-DPTT-COF are of similar bandgaps but of varied energy positions due to the different orientations of imine. Besides, characterizations disclose that DPTT-Py-COF delivers more enhanced charge separation and transfer than Py-DPTT-COF. Probed by the oxidation of amine to imine, DPTT-Py-COF exhibits a blue light photocatalytic performance superior to that of Py-DPTT-COF. DPTT-Py-COF, a highly recyclable photocatalyst, enables the oxidation of various amines to imines with oxygen. This work highlights that tuning the microenvironment of COFs unravels tenable performances in photocatalysis.

Effect of Thiophene-Hydrazinyl-Thiazole derivative as an efficient dye sensitizer and performance enhancer of TiO2 toward rhodamine B photodegradation

Visible-light-driven photocatalysis is an eco-friendly technology for wastewater treatment, where TiO2-based photocatalysts displayed outstanding performance in this regard. Dye sensitization is a promising approach for overcoming the common drawbacks of TiO2via improving its photocatalytic performance and extending its activity to visible light. Herein, we demonstrate the synthesis of the Thiophene-Hydrazinyl-Thiazole (THT) derivative as a novel organic dye sensitizer to be employed as a visible-light antenna for TiO2 nanoparticles. The physicochemical characteristics of the as-synthesized TiO2-based nanoparticles are examined by different techniques, which revealed the successful fabrication of the proposed THT-TiO2 heterojunction. The incorporation of THT molecules on the TiO2 surface led to slight disorders and deformation in the crystal lattice of TiO2, a remarkable improvement of its absorption in the visible light as a perfect visible-light antenna in the whole visible region, and significant enhancement in the charge transfer. Rhodamine B (RhB) is used as an organic dye model to assess the photocatalytic efficiency of the as-fabricated THT-TiO2 photocatalyst which achieved almost complete degradation (>95% in 150 min) with an observed rate constant (kobs) of 0.0164 min−1; total organic carbon (TOC) measurements suggested ∼75% mineralization. THT-TiO2 achieved 2.1-fold enhancement in photodegradation% and 4.1-fold enhancement in kobs compared to the bare TiO2. THT showed good activity under visible-light irradiation (RhB degradation% was >66% in 150 min and kobs = 0.0085 min−1). The influence of the initial pH of the solution was investigated and pH 4 was the optimum pH value for suitable interaction between RhB and the surface of THT-TiO2. Radical quenching experiments were conducted to assess the crucial reactive species where the ∙OH and O2.− were the most reactive species. THT-TiO2 showed promising stability over three successive cycles. Finally, the improvement mechanism of the photocatalytic activity of THT-TiO2 was attributed to the electron injection from the excited THT (the dye sensitizer) to TiO2 and enhanced charge separation.

Efficient pathways for photogenerated charge transfer induced by Co dopants in WO3/TiO2 nanorod arrays

Modifying the energy band structure in heterostructured photocatalysts enhances charge separation efficiency and improves photoelectrochemical (PEC) performance by decreasing the charge transfer barrier. In this study, cobalt doping into WO3/TiO2 core/shell heterojunction nanorod arrays introduces versatile valence states of cobalt altering the oxygen coordination environment around W atoms in WO3, resulting in an increase in W5+ ions and oxygen vacancy defects in WO3 lattice, facilitating the water splitting reaction. Photogenerated electrons transfer easily from the WO3:Co shell to the TiO2 core due to the lower conduction band minimum (CBM) of WO3:Co shell. Moreover, photogenerated holes transfer from the TiO2 core to the WO3:Co shell efficiently due to the higher valence band maximum (VBM) of TiO2 core. The heterostructure has a high photogenerated carrier density (9.89 × 1018 cm-3), improving photoconversion efficiency (2.55 mA cm-2 at 1.23 V vs. RHE) and reducing charge recombination rates (6.51 × 10–4 s-1). Co doping increases the -OH bond on WO3/TiO2 surface, improves its hydrophilicity, and is more conducive to the reaction in aqueous electrolyte. Additionally, the nanorod array structure facilitates PEC reaction kinetics by providing open spaces for mass exchange. This work proposes a feasible strategy for improving photogenerated charge transport and enhancing PEC by combining regulation of the band structure of WO3/TiO2 heterostructures with morphology design.

Chemical and green synthesized Co/Ni-doped hematite nanoparticles for enhancing the photocatalytic and antioxidant properties

This research focuses on developing environmentally friendly and economically viable Co/Ni-doped hematite nanoparticles (HNPs) through both chemical and green synthesis methods and evaluated their potential for biomedical and environmental applications. The chemical synthesis employs polyvinylpyrrolidone (PVP), while the green approach utilizes Azadirachta indica (A. indica) leaf extract as a stabilizing agent. Co/Ni-doped HNPs are crystalline size ranging from 14 to 21 nm, morphology analysis revealed that the NPs exhibited a quasi-spherical, with an average particle size ranging from 15.98 to 25.91 nm, and dopants confirmed to contain by the XPS spectra. VSM study explains magnetic parameters, coactivity, residual magnetism, and magnetization. A. indica plants contain quinones, saponins, glycosides, alkaloids, and flavonoids. Characterization of the nanoparticles reveals optimized Co/Ni-doped HNPs with enhanced photocatalytic activity. These nanoparticles exhibit a remarkable 93%–95% degradation of UV-reactive dyes (methyl orange and methylene blue) within 90 min, attributed to structural and surface modifications that improve light absorption and enhance charge separation. The study concludes that green-synthesized Co/Ni-doped HNPs outperform chemically synthesized counterparts as superior photocatalysts. Additionally, antioxidant evaluations using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) assays suggest significant antioxidant capabilities. A high scavenging activity percentage, ranging from 83% to 88%, was observed, which increased with higher concentrations of the synthesized Co/Ni-doped HNPs making these nanoparticles suitable for biomedical and environmental applications that require a magnetic system. In this study, the IC50 values for the antioxidant activity of chemically and green synthesized Co/Ni-doped hematite nanoparticles against the DPPH/NO assay were calculated to be 18.33 μg ml−1 and 16.09 μg ml−1, respectively. The research highlights the multifunctional properties of Co/Ni-doped HNPs, addressing the demand for tailored inorganic magnetic nanoparticles with minimal ecological impact.

Visible-light responsive photocatalytic fuel cell with gas-diffusion g-C3N4/TiO2 heterojunction photoanode for simultaneously degrading VOCs and generating electricity

The use of a gas diffusion photoanode for a photocatalytic fuel cell is promising to simultaneously degrade VOCs and generate electricity. However, conventional gas-diffusion photoanode faces the issues of inefficient solar energy utilization and serious electron-hole recombination. Herein, a visible-light-responsive gas-diffusion g-C3N4/TiO2 heterojunction photoanode is developed for simultaneous degradation of toluene and generation of electricity. In addition to the intrinsic feature of reduced mass transfer resistance of VOCs to the photocatalytic surface, such a gas-diffusion photoanode not only extends the photo-response spectrum, but also enhances charge separation. Accordingly, the photocatalytic fuel cell with the newly-developed photoanode demonstrates superior discharging performance and toluene removal efficiency over the gas-diffusion TiO2 and g-C3N4 photoanodes. The maximum power density achieved by the gas-diffusion g-C3N4/TiO2 heterojunction photoanode is 0.0375 mW/cm², while the maximum toluene removal efficiency reaches 43.8 %. This study has promoted the development of photocatalytic fuel cells for the degradation of VOCs and electricity generation.

Manipulating Photoconduction in Supramolecular Networks for Solar-Driven Nitrate Conversion to Ammonia and Oxygen.

For photoelectrodes to be used in practical catalytic applications, challenges exist in achieving the efficient production and transport of photogenerated charge-separated states. Analogous concepts in traditional inorganic photoelectrodes can be applied to their organic-polymer counterparts with improved charge-separation efficiencies. In this work, we develop photoconductive organic networks to form a high-performance photoelectrode for NO3- reduction to NH3. In the integrated network, interfaces between the organic electron-donating photoconductor and electron-accepting catalyst can generate charge carriers efficiently upon illumination, leading to enhanced charge separation for photoelectrocatalysis. The photoelectrode network is capable of converting NO3- to NH3 at an external quantum efficiency of 13%. By coupling with a BiVO4 photoanode in tandem, the system reduces NO3- to NH3 and oxidizes H2O to O2 simultaneously at Faradaic efficiencies of 95-98% with sustained photocurrents and production yields. Investigation of the photoconductive network by steady-state/time-resolved spectroscopies reveals the efficient generation and transport of free charge carriers in the photoelectrode, providing a basis for high photoelectrocatalytic performances.

Identifying Root Origin of Insulating Polymer Mediated Solar Water Oxidation.

Rational construction of high-efficiency photoelectrodes with optimized carrier migration to the ideal active sites, is crucial for enhancing solar water oxidation. However, complexity in precisely modulating interface configuration and directional charge transfer pathways retards the design of robust and stable artificial photosystems. Herein, a straightforward yet effective strategy is developed for compact encapsulation of metal oxides (MOs) with an ultrathin non-conjugated polymer layer to modulate interfacial charge migration and separation. By periodically coating highly ordered TiO2 nanoarrays with oppositely charged polyelectrolyte of poly(dimethyl diallyl ammonium chloride) (PDDA), MOs/polymer composite photoanodes are readily fabricated under ambient conditions. It is verified that electrons photogenerated from the MOs substrate can be efficiently extracted by the ultrathin solid insulating PDDA layer, significantly boosting the carrier transport kinetics and enhancing charge separation of MOs, and thus triggering a remarkable enhancement in the solar water oxidation performance. The origins of the unexpected electron-withdrawing capability of such non-conjugated insulating polymer are unambiguously uncovered, and the scenario occurring at the interface of hybrid photoelectrodes is elucidated. The work would reinforce the fundamental understanding on the origins of generic charge transport capability of insulating polymer and benefit potential wide-spread utilization of insulating polymers as co-catalysts for solar energy conversion.

Ti3C2 quantum dots-modified oxygen-vacancy-rich BiOBr hollow microspheres toward optimized photocatalytic performance

The Ti3C2 quantum dots (QDs)/oxygen-vacancy-rich BiOBr hollow microspheres composite photocatalyst was prepared using solvothermal synthesis and electrostatic self-assembly techniques. Together, Ti3C2QDs and oxygen vacancies (OVs) enhanced photocatalytic activity by broadening light absorption and improving charge transfer and separation processes, resulting in a significant performance boost. Meanwhile, the photocatalytic efficiency of Ti3C2 QDs/BiOBr-OVs is assessed to investigate its capability for oxygen evolution and degradation of tetracycline (TC) and Rhodamine B (RhB) under visible-light conditions. The rate of oxygen production is observed to be 5.1 times higher than that of pure BiOBr-OVs, while the photocatalytic degradation rates for TC and RhB is up to 97.27% and 99.8%, respectively. The synergistic effect between Ti3C2QDs and OVs greatly enhances charge separation, leading to remarkable photocatalytic activity. Furthermore, the hollow microsphere contributes to the enhanced photocatalytic performance by facilitating multiple light scatterings and providing ample surface-active sites. The resultant Ti3C2QDs/BiOBr-OVs composite photocatalyst demonstrates significant potential for environmental applications.

Flexible roles of TiO2 in enhancing carrier separation for the high photocatalytic performance of water treatment under different spectrum sunlight

Construction of heterogeneous-photocatalysts is an effective mean for enhancing charge separation, however, the specific roles of the individual components have not been thoroughly explored. In this article, a heterogeneous-photocatalyst, TiO2/MoO3-x, was constructed, revealing that the two components, TiO2 and MoO3-x, play varying roles under different light spectra. Under full spectrum light, an S-scheme mechanism was achieved, which preserved the high oxidizing and reducing property of MoO3-x and TiO2, facilitating an augmented generation of reactive oxygen species (ROS). Under visible light, the MoO3-x functioned as the donor of hot electrons and the TiO2 served as the receptor platform for these electrons. The presence of the interfacial electric field enabled the transfer of hot electrons, leading to an enhanced ROS generation. Consequently, the TiO2/MoO3-x achieved high photocatalytic activity under both full spectrum and visible light. The optimized TiO2/MoO3-x catalyst demonstrated outstanding antibacterial efficacy, achieving eradication rates of 98.1 % for Staphylococcus aureus, and 99.6 % for Escherichia coli respectively. Additionally, it exhibited substantial degradation activity with a rate of 0.028 min−1 for Rhodamine B (50 mg/L). Furthermore, the TiO2/MoO3-x membrane removed approximately 81.2 % of bacteria from surface water, underscoring the potential of the designed membrane in water purification systems. This article explored the distinct roles and corresponding charge transfer mechanisms of the TiO2 and MoO3-x under full spectrum or visible light, offering innovative ideas for the design of full-spectrum photocatalysts with high efficiency. The straightforward design of membrane-based filtering device demonstrated wide applications for treating wastewater for the removal of dye and bacterial contamination.

Visible-light-driven photocatalytic oxidation of furfural to furoic acid over Ag/g-C3N4

Furoic acid (FA) is a useful bio-chemicals, which can be used in the production of pharmaceuticals, food additives, flavors, industrial chemicals, biofuels, etc. Oxidation of furfural to FA has been carried out by a thermal catalytic method, but photocatalytic oxidation protocol has not been reported yet. Here, g-C3N4-supported Ag nanoparticles (Ag NPs) catalysts with different Ag loading were synthesized and used for the photocatalytic oxidation of furfural to FA under visible light irradiation. The physicochemical and photoelectrochemical properties of the catalysts were systematically investigated by XRD, TEM, XPS, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), photoluminescence, etc. Compared with the pristine g-C3N4, Ag-CN(N2 + H2) was found to have better photocatalytic performances in the aerobic oxidation of furfural under visible light irradiation, and the conversion can reach 82 % with a FA yield of 30 %. Importantly, the loading of Ag NPs has a significant effect on the photoelectrochemical properties. Specifically, 0.5 % Ag NPs loading maximized the photocurrent response, indicating that the loading of Ag NPs enhances charge separation and migration under visible light excitation. The introduction of Ag NPs also led to a significant decrease in electrochemical impedance, which promoted the rate of electron transfer at the interface, further confirming the improved photocatalytic efficiency. The addition of Ag NPs broadens the solar absorption and promotes the separation/transport of photo-generated carriers to form “hot electrons”, and provides the active species for furfural oxidation. The reasonable reaction mechanism of the photocatalytic oxidation of furfural to FA was elucidated. This work offers a novel method for the oxidation of furfural to FA in a mild and green way.

Elucidating the photocatalytic mechanism of biomass-derived carbon dots nanocomposite for efficient degradation of MB and CR dyes: Insights into protein binding applications

This study introduces an environmentally sustainable method for synthesizing a nanocomposite using carbon quantum dots derived from green tea waste and zinc oxide. The single-step hydrothermal process not only addresses waste management but also yields a versatile nanocomposite with diverse applications. Rigorous characterization reveals its morphology, crystallinity, phase identification, structural behavior, optical properties, and chemical composition. Incorporating carbon quantum dots into the zinc oxide matrix reduces the band gap to 1.87 eV, enhancing charge separation and light-harvesting. This modification significantly boosts photocatalytic activity, achieving degradation efficiencies of 95.16 % for methylene blue (MB) and 93.21 % for congo red (CR) under visible light. The effects of pH, contact time, and photocatalyst concentration on dye degradation were explored. The nanocomposite, exhibiting both adsorption and photocatalytic performance, is poised for broad applications. Fluorescence quenching studies with lysozyme protein provide insights into potential applications across diverse fields, highlighting its environmentally friendly and multifunctional attributes.

Development of hydrothermal carbonaceous carbon/NH2-MIL-101(Fe) composite photocatalyst with in-situ production and activation of H2O2 capabilities for effective sterilization

Photocatalytic production of H2O2 has garnered significant attention, but the use of sacrificial reagents in H2O2 photosynthesis and the subsequent limited H2O2 activation efficiency would impede its practical application in water decontamination. In this work, hydrothermal carbonaceous carbon/NH2-MIL-101(Fe) (abbreviated as HTC-cf/NMIL-101(Fe)) heterojunction was fabricated through a solvothermal strategy, and serving as a self-sufficient photo-Fenton-like catalyst to in-situ generate and activate H2O2. Hydrothermal carbonaceous carbon derived from cost-effective waste coffee grounds, serving as a green and sustainable photocatalyst, demonstrated high H2O2 production rate of 612 μmol/g/h without the need for sacrificial reagents or aeration assistance. Moreover, the excellent self-sufficient photo-Fenton activity for HTC-cf/NMIL-101(Fe) can be obtained, which ascribed to the synergistic effect of self-generated H2O2 production as well as the in-situ catalytic H2O2 decomposition of •OH by Fe species in NMIL-101(Fe) and photogenerated electrons. The optimized HTC-cf/NMIL-101(Fe) photocatalyst showed simultaneous improvements in both H2O2 production and activation capabilities. Impressively, the effective circulation of Fe3+/Fe2+ in NMIL-101(Fe), aided by photogenerated electrons, results in a 5-fold increase toward H2O2 decomposition rate constant (Kd) compared to HTC-cf alone under light irradiation in open-air conditions. The enhanced charge separation and appropriate band structure of HTC-cf/NMIL-101(Fe) photocatalyst assured the high selectivity of two-electron O2-reduction to H2O2. HTC-cf/NMIL-101(Fe) displayed excellent photocatalytic sterilization efficiency against E. coli and S. aureus under visible light, and its sterilization application in actual water was also demonstrated. Notably, the adaptability of this system to ambient conditions, including open-air atmosphere, non-sacrificial reagents, and low leaching of Fe ions, highlights the promising practical utility of the HTC-cf/NMIL-101(Fe) photocatalyst.

Positively charged 3-D interface mediated electrostatic adsorption of microorganisms for enhanced photocatalytic disinfection

Photocatalysis offers a sustainable method for disinfecting natural drinking water. However, the photoactive species generated at the catalyst interface face challenges in migrating over long distances in water to interact with bacteria. In this study, we introduce an enhanced photocatalytic disinfection strategy involves the in-situ growth of fluorine-modified titanium dioxide heterostructure arrays on carbon fibers. This method results in a positively charged photocatalytic fabric that effectively attracts negatively charged microbes to its surface, significantly reducing the mass-transfer distance of active species. The heterophase junction between rutile nanorods and anatase nanoparticles enhances charge separation efficiency, while fluorine doping in anatase nanoparticles creates a positively charged 3-D interface conducive to electrostatic adsorption and in-situ oxidation of microorganisms. When tested in actual rainwater, this photocatalytic fabric successfully reduced the bacterial count from 4500 CFU/mL to below the WHO drinking water standard of 100 CFU/mL over three cycles in a single day under natural sunlight.

(Invited) Molecular Mechanisms That Enhance Charge Separation at Donor-Acceptor Interfaces in Non-Fullerene Organic Photovoltaics

We analyze molecular mechanisms that enhance charge separation at donor-acceptor interfaces in non-fullerene organic photovoltaics by means of molecular dynamics calculations, quantum chemistry, and QM/MM approach. We consider interfaces of π-conjugated polymers (PM6) and non-fullerene acceptors (Y6 and ITIC) as a model system. We clarified the effect of molecular disorders at the interface on the charge separation efficiency.