Enhanced Charge Transfer Research Articles

High-efficiency PMS activation by difunctional Co-Fe PBA/g-C3N4 S-scheme heterojunction for oxytetracycline degradation: Performance evaluation and mechanism insight

The utilization of sulfate radical-based advanced oxidation processes (SR-AOPs) has captivated the academic community due to their minimal energy requirements and superior efficacy in peroxomonosulfate (PMS) activation for pollutant decomposition. Notwithstanding these advantages, engineering an effective and economical catalyst for PMS activation presents a considerable hurdle. In the present study, a metal-organic framework of CoFe PBA is ingeniously anchored onto g-C3N4 nanosheets, resulting in the formation of an innovative CoFe PBA/g-C3N4 S-scheme heterojunction that demonstrates remarkable efficiency in PMS activation. Intriguingly, the catalytic efficiency of CoFe PBA/g-C3N4 surpasses that of g-C3N4 and CoFe PBA by 7-fold and 2.33-fold, respectively. The heightened activity of CoFe PBA/g-C3N4 heterojunction is attributed to the enhanced charge transfer efficiency, a consequence of the successful heterojunction formation. Concurrently, the ability of photoexcited electrons to reduce Co3+/Fe3+ to Co2+/Fe2+ bolsters PMS activation. Significantly, this heterojunction retains unparalleled stability in degrading oxytetracycline without discernible performance attenuation, heralding its commendable prospects in real-world applications. Besides, mechanism exploration indicates that SO4−, h+, and electron transfer contribute to oxytetracycline degradation in the CoFe PBA/g-C3N4 system. This investigation serves as a beacon for the strategic development of highly active and stable catalysts for PMS activation, aiming at environmental decontamination.

Enhanced Charge Transfer in Poly(Heptazine Imide) Synergistically Induced by Donor-Acceptor Motifs and Ohmic Junctions for Efficient Photocatalytic CO2 Reduction.

Poly(heptazine imide) (PHI) has received widely interest in the photocatalytic CO2 reduction due to its good crystallinity and complete in-plane structure. However, its poor photo-induced carrier separation and migration efficiency and insufficient active sites results in undesirable photocatalytic CO2 reduction performance. Herein, we designed and constructed a novel ohmic junction photocatalyst by integrating melamine edge-modified PHI (mel-PHI) with extended π-conjugated system with TiN (TiN/mel-PHI) for enhancing the photocatalytic CO2 reduction activity. Strikingly, the photocayalytic CO2 reduction yield of the optimal TiN/mel-PHI is 62.64 µmol·g-1·h-1, which is 5.6 and 2.8 times higher than PHI (11.26 µmol·g-1·h-1) and mel-PHI (22.32 µmol·g-1·h-1), respectively. The superior photocatalytic CO2 reduction activity is attributed not only to the formation of D-A structure by the introduction of melamine, which extends the π-conjugation system, alters the electronic structure of PHI, and accelerates the charge separation and migration, but also to the induced internal electric field by ohmic junction further enhances the charge separation and migration efficiency. Meanwhile, the synergistic effect of mel-PHI and TiN enriched the electron number of TiN, reducing the CO2 reduction potential. This work highlights the synergistic enhancement of charge transfer between D-A motifs and ohmic junctions, confirming their potential in optimizing photocatalysts.

Synergistic effect of molybdenum dioxide wrapped nitrogen doped carbon nanotubes in binder-free anodes for enhanced lithium storage properties

Molybdenum dioxide (MoO2) is regarded as a potential anode for lithium-ion batteries due to its highly theoretical specific capacity. However, its further application in lithium-ion battery is largely limited by insufficient practical discharge capacity and cyclic performance. Here, MoO2nanoparticles are in-situ grown on three-dimensional nitrogen doped carbon nanotubes (NCNTs) on nickel foam substrate homogeneously using a simple electro-deposition method. The unique structural features are favorable for lithium ions insertion and extraction and charge transfer dynamics at electrode/electrolyte interface. As a proof of concept, the as-synthesized nanocomposites have been employed as anode for lithium-ion battery, exhibiting a reversible and significantly improved discharge capacity of ∼517 mA h g-1at the current density of 150 mA g-1as well as superior cycle and rate performance. The first-principle calculations based on density functional theory and electrochemical impedance spectroscopy results demonstrate a reduced energy barrier of lithium ions diffusion, improved lithium storage behavior, reduced structure collapse, and significantly enhanced charge transfer kinetics in MoO2/NCNTs nanocomposites with respect to MoO2powder. The excellent performance makes as-prepared MoO2/NCNTs nanocomposites promising binder-free anode for high performance lithium-ion batteries. This work also provides important theoretical insights for other state-of-the-art batteries design.

Double Carbon-Species Coated Porous Silicon Anode Induced by Interfacial Energy Reduction for Lithium-Ion Batteries.

The rapid development of electric vehicles necessitates high-energy density Li-ion batteries for extended range. Silicon is a promising alternative to graphite anodes due to its high capacity; however, its substantial volume expansion during cycling leads to continuous growth of the solid electrolyte interphase and significant capacity fading. This study addresses these issues by designing a porous Si structure combined with a double carbon-species coating layer, induced by low interfacial energy in a scalable process. Carbon and graphene are located on Si surfaces, forming a close interface that maintains electrical contact, suppresses lithium consumption, and enhances charge transfer properties. The composite anode with a double carbon-species coating on Si demonstrates rapid stabilization with increasing coulombic efficiency, achieving a specific capacity of 1,814 mAh g-1 at 0.2 C and a high-rate capability of 1,356 mAh g-1 at 10C. Additionally, in a full-cell configuration with LiFePO4, it recorded a specific capacity of 161 mAh g-1 at 0.2 C. These results show the potential of porous Si with a carbon-graphene coating for stable, high-capacity operation in Li-ion batteries, offering new insights into high-performance electrochemical systems. Moreover, the double carbon-species coating derived from a scalable surface chemistry-based process presents a realistic alternative for industrial applications.

Magnetic PDMS@SiO2/Fe3O4 Composite Friction Layer Material for Enhanced Friction Nanogenerator Output Performance

Triboelectric nanogenerators (TENG) have exhibited remarkable potential in harnessing stochastic low-frequency mechanical energy from oceanic surfaces, attributed to their versatile architectures and capability for extensive deployment. Nonetheless, the relatively modest power output per unit area remains a critical limitation impeding the advancement of TENG technology. Consequently, the innovation of novel material systems and devices to augment the output performance and efficiency of TENG is paramount in achieving effective ocean energy exploitation. In our study, a vertical contact PC-TENG was utilized as an energy harvester, with the incorporation of magnetic nano-oxide particles to bolster the output efficiency of TENG. This investigation represents the inaugural application of SiO2 and Fe3O4 nanoparticles within PDMS negative friction layers. This strategy augments the specific surface area, thereby improving the contact between the friction materials and enhancing charge transfer efficiency. Moreover, the magnetic properties of Fe3O4 facilitate charge separation on the material's surface, culminating in an elevated voltage output. Comprehensive characterizations were conducted using SEM, FTIR, electrometer, and contact angle meter, while simulations were corroborated with COMSOL Multiphysics field simulation software. The output performance witnessed optimization through the incorporation of Fe3O4, culminating in a peak open-circuit voltage (VOC) of 85.1212 V, a maximum short-circuits current (ISC) of 8.4037 μA, and a maximum transferred charge (QSC) of 0.5638 nC, reflecting enhancements of 28%, 32%, and 27%, respectively, compared to conventional PDMS materials. The peak output power, achieved with an impedance match of 55 MΩ, was recorded at 19.03 mW, marking a 70.8% improvement in output performance. The findings revealed that the contact angle of PDMS@SiO2/Fe3O4 composites reached 100.092°, enhancing hydrophobicity by 8% relative to traditional PDMS materials, thereby rendering it more suitable for humid environments. COMSOL Multiphysics field simulation results further substantiated the viability of the PDMS@SiO2/Fe3O4 composite friction layer material for applications in oceanic wave environments. Ultimately, a rectifier bridge was introduced to convert the alternating current generated by the PC-TENG into direct current. This research offers a novel paradigm for the utilization of TENG in the realm of marine energy.

Pr3+ ions activated TiO2 nanoparticles as electron transport layer for copper based (CH3NH2)2CuBr4 perovskites solar cells

In emerging organic-inorganic perovskite solar cells (PSCs), the role of efficient electron transport layers (ETLs) is critical for electron transfer and hole blocking. TiO2 is one of the widely reported ETLs but limits the performance of the devices exhibiting restricted electron mobility and numerous defect states. The process of doping rare earth ions has been an effective approach in improving the electronic and optical properties of TiO2 for enhanced efficiency of PSCs. The present work studies the effect of praseodymium (Pr3+) doped TiO2 prepared via sol-gel technique as electron transport layers for lead-free perovskite solar cells. The X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS) studies showed that the crystallite size and bandgap of the particles reduced as a function of Pr3+ doping concentration. The X-ray photoelectron spectroscopy (XPS) analysis of the samples inferred that Pr3+ ions majorly remained on the TiO2 surface. Copper-based (CH3NH2)2CuBr4 perovskites were synthesized by solution method as an active layer for the solar cells. XRD, FTIR (Fourier Transform Infrared Spectroscopy) and XPS analysis confirmed the formation of 2D-perovskite phase of the samples. The scanning electron microscopy (SEM) analysis of the perovskites revealed well crystalline orthorhombic structures. Current-voltage measurements were carried out to study better passivation properties with rare-earth doping of the ETLs and was found to be most enhanced for 0.07 Pr3+ concentration. Electro-chemical Impedance Spectroscopy (EIS) studies of the solar cells showed a reduced interface recombination and enhance charge transfer properties as a function of rare-earth dopant concentration. Further, the fabricated perovskite solar cells showcased better performance with xPr3+:TiO2 ETLs and the maximum efficiency of ∼1.25 % was obtained for TiO2: 0.07 Pr3+.

Nickel coated paper electrode constructed by interfacial electrodeposition for biomass upgrading at industrial current density

Substituting the kinetically slow oxygen evolution reaction (OER) with biomass electrooxidation significantly decreases the energy demand of water electrolysis. However, exploring and optimizing efficient electrocatalysts remains a challenge for large−scale production of valuable chemicals and hydrogen. Herein, we have constructed a nickel coated paper electrode (NiCo@Ni/CP) composed of crystalline Ni metal and amorphous NiCo hydroxide nanosheets layers via interfacial electrodeposition on carbon paper (CP) for monosaccharide oxidation reactions (MOR), which achieved a formate yield of 82.4 %. Remarkably, the flow electrolyzer maintained an industrial−grade current density of 1 A cm−2 at 1.70 V with exceptional stability over 100 h, also displaying significant co−generation Faradaic efficiencies of approximately 80.0 % and 97.3 % for formate and hydrogen production, respectively. The superior performance is attributed to the redistribution of electrons at the Ni and amorphous NiCo hydroxide interface, which enhances charge transfer and reactant adsorption by adjusting the d−band center, hence reducing deprotonation and C−C bond cleavage energies of xylose during MOR. This work provides a promising strategy for the design of efficient catalysts for biomass upgrading and the production of hydrogen at high current densities.

Oxygen vacancies-enriched spent lithium-ion battery cathode materials loaded catalytic membrane for effective peracetic acid activation and organic pollutants degradation

Advanced oxidation processes combined with membrane filtration technique offer a promising approach for pollution mitigation and catalyst recovery. Herein, a waste ternary lithium-ion battery cathode material of LiNixCoyMnzO2 (LNCM) loaded polytetrafluoroethylene (PTFE) membrane was synthesized for peracetic acid (PAA) activation (LNCM-PTFE/PAA) and 2,4,6-trichlorophenol (TCP) degradation. Such a novel membrane, with a catalyst loading of 10 mg (0.796 mg/cm2) of LNCM achieved 96.4 % removal of TCP (2 mg/L) within 20 min in neutral pH. The redox cycles of surface metals (such as Co3+/Co2+, Ni3+/Ni2+, and Mn4+/Mn3+/Mn2+) in spent LNCM efficiently enhance charge transfer and mediated PAA activation. And intrinsic oxygen vacancies in LNCM facilitated PAA adsorption and its cleavage. The resulting carbon-centered radicals (R-C•, CH3C(O)OO•) and 1O2 are identified as the primary reactive species that collaboratively participate in TCP degradation. Quantitative structure-activity relationship analysis demonstrated a substantial reduction in product toxicity. The successful practical application of the LNCM-PTFE/PAA membrane was exemplified by treating chlorophenol industrial wastewater. This study presents a new LNCM-PTFE/PAA catalytic membrane for high-efficiency water treatment and a novel perspective for green utilization of waste LNCM.

Spherical Ru/FeOx composite as a bifunctional electrocatalyst for overall water splitting in neutral media

Electrochemical water splitting stands out as a promising technology for H2 production, due to its simplicity and high energy conversion efficiency. Therefore, it is a key issue to develop and design efficient catalysts for overall water splitting (OWS), especially in neutral media. Herein, the present study presents a stable bifunctional electrocatalyst, namely a spherical structure consisting of ruthenium and iron oxide composite supported on iron foam (Ru/FeOx), which was prepared using a simple two-step process. In 1.0 M PBS, the optimized Ru/FeOx-300 demonstrates low overpotentials of 30 and 212 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at 10 mA cm−2, respectively. More impressively, Ru/FeOx-300 requires only 1.505 V to achieve a current density of 10 mA cm−2 and exhibits superior electrochemical stability for 24 h in a two-electrode neutral electrolyzer. The outstanding catalytic performance and stability of Ru/FeOx-300 nanospheres for water splitting are attributed to the binder-free integrated structure, the enhanced charge transfer facilitated and the synergistic effect between Ru and FeOx. This study offers a novel approach to the development of high-efficiency electrocatalysts for overall water splitting in neutral media.

Metalloid Phosphorus Induces Tunable Defect Engineering in High Entropy Oxide Toward Advanced Lithium‐Ion Batteries

AbstractThe inferior electrical conductivity and sluggish lithium storage kinetics of conventional high‐entropy oxide (HEO) are critical issues hindering their commercialization. The high electronegativity of metalloids can ameliorate this predicament by altering the electronic configuration of HEO compared to metals. Herein, metalloid phosphorus doping in spinel‐type HEO (PxA1‐x)B2O4 (A/B = Cr, Mn, Fe, Co, Ni) (P‐HEO) is achieved through a facile sol–gel process. The metalloid phosphorus doping facilitates the transfer of electrons from transition metal sites to phosphorus‐doped sites, resulting in the formation of electron‐rich and electron‐deficient local regions on the HEO surface and is conducive to an increase in the total number of active lithium sites in the electrochemical reaction process. Density functional theory calculation reveals Li adsorption energy on the synthesized P‐HEO is only −1.102 eV, demonstrating that the phosphorus doping enables a strong electronic coupling between lithium ions and P‐HEO. Furthermore, metalloid phosphorus doping also leads to oxygen vacancies formation and lattice distortion, which significantly enhances charge transfer efficiency and diffusion kinetics and results in the enhanced lithium storage performance with impressive rate capability and long‐term stability. These findings provide valuable insights for the design of lattice‐engineered HEO as versatile electrodes for future energy storage applications.

Impact of electron acceptors on mechanochromism in carbazole-based charge transfer complexes

The synthesis of a dicarbazole derivative (C4C) with a flexible alkyl chain was conducted, and its charge transfer complexes (CTCs) were prepared by incorporating three acceptors (3,4,5,6-tetrafluorophthalonitrile (TFPN), 2,3,5,6-tetrafluoroterephthalonitrile (TFTPN), 1,2,4,5-tetracyanobenzene (TCNB)), aiming to investigate the influence of electron acceptors on their mechanofluorochromism (MFC). It was observed that CTC3 containing TCNB displayed the longest emission wavelength due to the lowest LUMO energy level of TCNB. Interestingly, while CTC1 with TFPN emitted green fluorescence, CTC2 incorporating TFTPN showed a shorter emission wavelength than that of CTC1 although TFTPN had a lower LUMO energy level than TFPN. Single-crystal structural analysis revealed that loose packing between donor and acceptor in CTC2 contributed to its shorter emission wavelength. Notably, CTC2 exhibited MFC because of enhanced charge transfer interaction after grinding. However, no MFC behaviors were observed for the other two complexes. These findings highlight that electron acceptors not only impact photoluminescent properties but also strongly influence response towards mechanical forces.

Electrostatic Confinement‐Induced Excited Charge Transfer in Ionic Covalent Organic Framework Promoting CO2 Reduction

We demonstrate an electrostatic confinement‐induced charge transfer pathway in a supramolecular photocatalyst comprising of an ionic covalent organic framework (COF) and cationic metal complexes. The dynamic electrostatic interactions not only attract cations around the COF to accept photogenerated electrons, but also allows for a retention of homogeneous catalytic characters of complexes, making a subtle balance. Accordingly, the electrostatic confinement effect facilitates the forward electron transfer from a photoexcited COF to cationic Co complex, realizing a remarkable photocatalytic CO2 reduction performance. Its catalytic efficiency is far superior to the supramolecular counterparts with Van‐der‐Waals or hydrogen bonding interactions. This work presents an insight for enhancing charge transfer in supramolecular systems, and provides an effective approach for construction of highly efficient photocatalysts.

A Wearable Electrochemical Sensor Based on Single-Atom Pt Anchored on Activated NiCo-LDH/Ti3C2Tx for Real-Time Monitoring of Glucose.

Wearable, noninvasive sweat sensors enable real-time monitoring of metabolites in human health management. However, the commercial enzyme-based and currently nonenzymatic glucose sensor represents sluggish glucose oxidation kinetics and a narrow sensing range. Rational design of sensitive materials is significant yet faces a huge challenge. Herein, we construct a single-atom Pt supported on NiCo-LDH/Ti3C2Tx heterostructures (Pt1-NiCo-LDH/Ti3C2Tx) as the nonenzymatic electrochemical glucose sensor sensitive materials for selective detection of glucose level in human sweat. The obtained Pt1-NiCo-LDH/Ti3C2Tx with improved structural stability and enhanced charge transfer efficiency shows a low oxidation peak potential of 0.49 V, high sensitivity of 506.6 μA mM-1 cm-2, a low detection limit of 0.035 μM, and long-term stability toward the glucose detection. The wearable sensor, coupled with a wireless transmission module and a signal processing chip, is used for real-time perspiration glucose monitoring during outdoor exercise. The result is comparable to that of high-performance liquid chromatography (HPLC). This research provides a new paradigm for designing a wearable nonenzymatic electrochemical glucose sensor, enabling noninvasive real-time monitoring of glucose concentrations in human sweat.

Mechanisms of Thermal Decomposition in Spent NCM Lithium-Ion Battery Cathode Materials with Carbon Defects and Oxygen Vacancies.

Resource recovery from retired electric vehicle lithium-ion batteries (LIBs) is a key to sustainable supply of technology-critical metals. However, the mainstream pyrometallurgical recycling approach requires high temperature and high energy consumption. Our study proposes a novel mechanochemical processing combined with hydrogen (H2) reduction strategy to accelerate the breakdown of ternary nickel cobalt manganese oxide (NCM) cathode materials at a significantly lower temperature (450 °C). Particle refinement, material amorphization, and internal energy storage are considered critical success factors for the accelerated decomposition of NCM cathode materials. In our proposed approach, NCM cathode materials can develop active sites with carbon defects (Cv) and oxygen vacancies (Ov), which improve the reduction and breakdown of H2. The adsorbed H2 on the surface of NCM decomposes into H* and combines with oxygen to form OH species, which can be facilitated by Ov via the enhanced charge transfer. The introduced Cv can enhance H2 cracking and generate *C-H species to promote the thermal decomposition of NCM. The presence of defects proves to foster the preferential reduction of Mn(IV) by H2, leading to a lower activation energy for the NCM decomposition (from 139 to 110 kJ/mol) with less H2 consumption. Life cycle assessment suggests a reduction of 4.42 kg CO2 eq for the recycling of every 1.0 kg of retired batteries. This study can promote material circularity and minimize the environmental burden of mining technology-critical metals for a low-carbon transition.

N-doped porous graphite with multilevel pore defects and ultra-high conductivity anchoring Pt nanoparticles for proton exchange membrane water electrolyzers

Water electrolysis for hydrogen production offers a promising solution to future energy crises and environmental challenges. Although platinum is an efficient catalyst for hydrogen evolution reactions (HERs), its high cost and stability challenges limit its widespread use. A novel platinum-based catalyst, comprising platinum nanoparticles on nitrogen-doped porous graphite (Pt-N-porous graphite), addresses these limitations. This catalyst prevents nanoparticle aggregation, provides a high specific surface area of 1308 m2 g−1, and enhances mass transfer and active site exposure. Additionally, it exhibits superior electrical conductivity compared to commercial Pt-C, enhancing charge transfer efficiency. The Pt-N-porous graphite catalyst achieves an overpotential of 99 mV at 100 mA cm−2 and maintains stable performance after 10000 cycles. Applied as a catalyst-coated membrane (CCM) in a proton exchange membrane (PEM) electrolyzer, it demonstrates excellent performance. Thus, the industrially synthesizable Pt-N-porous graphite catalyst holds great potential for large-scale energy applications.

Enhanced charge transfer kinetics across the graphdiyne-metal sulfide ohmic interface for boosting photocatalytic hydrogen evolution

The design and construction of photocatalysts are the crucial step for solar-driven hydrogen evolution. Herein, a new type of graphdiyne (CnH2n-2)-based photocatalyst, which was prepared by one pot method, was used to promote hydrogen evolution reaction by constructing GDY/VS2 ohmic junction with S sites anchoring on the surface. Actually, the unique two-dimensional conjugated carbon network of GDY can maintain the structural stability. The uneven surface facilitates the flow of electrons, which makes GDY a good electron donor. In addition, the expanded interlayer spacing of VS2 exposes more hydrogen evolution active sites. The increase in surface electronegativity of composite catalysts enhances their redox ability and charge transfer kinetics. The band edge of the graphdiyne-metal sulfide Ohmic contact interface is bent, allowing electrons to flow into the co catalyst without resistance. These synergistic effects lead to the robust hydrogen production of GDY/VS2, which was increased by nearly 10.3 times compared with that of pure GDY. Finally, charge migration at the interface of graphdiyne-metal sulfide heterojunction was proposed and further verified combining in situ XPS and theory calculation. This research marks a significant stride for enhance the efficiency of photocatalytic hydrogen evolution by designing and constructing composite heterojunction materials.

Enhanced optical, dielectric and transport properties in PVDF based (La0.5Bi0.5FeO3)0.5-(BaTiO3)0.5 composites

In this comprehensive study, we investigated PVDF composites incorporating LaBiFeO3-BaTiO3 (LaBiFO-BaTO) perovskite fillers, focusing on their structural, optical, dielectric, impedance, modulus and DC-conductivity properties. The fabrication involved precise preparation of LaBiFO-BaTO perovskite via solid-state reaction, ensuring phase purity conducive to composite integration. Using a solution casting method, PVDF films with varying LaBiFO-BaTO concentrations (5 %, 10 %, and 15 % wt) were successfully synthesized. XRD confirmed the synthesis of single-phase LaBiFO-BaTO and revealed structural modifications in PVDF composites, highlighting improved filler-matrix interactions at higher concentrations. Scanning electron microscopy and atomic force microscopy depicted the morphological evolution and surface roughness changes with increasing filler content. Optical studies indicated a red shift in absorption spectra with higher LaBiFO-BaTO concentrations, correlating with a decrease in the direct band gap energy of the composites. Electrical characterization demonstrated enhanced dielectric properties and impedance behaviour in PVDF/LaBiFO-BaTO composites, suggesting their suitability for applications in capacitors and optoelectronic devices. This systematic investigation provides valuable insights into optimizing PVDF-based composites for advanced functional materials. The composites exhibit enhanced dielectric permittivity at room temperature, attributed to space charge polarization and the high dielectric constant of LaBiFO-BaTO. Dielectric loss (tanδ) remains minimal (<0.1), decreasing with frequency, indicative of low energy dissipation suitable for high-frequency applications. Further the dielectric relaxation have been examined using Havrilak-Negami model. Impedance and modulus analyses reveal temperature-dependent behaviours, with reduced impedance and enhanced charge transfer kinetics in higher concentration composites. DC conductivity measurements demonstrate increased charge transport properties with temperature, influenced by thermally activated charge hopping mechanisms. Overall, PVDF/LaBiFO-BaTO composites show promising characteristics for capacitors, sensors, and optoelectronic devices, suggesting avenues for further optimization and broader application in advanced technologies.

Doping effects on boron carbide quantum dots for solar cells application: DFT study

The DFT method was used to explore the photovoltaic properties of nitrogen- and phosphorus-doped boron carbide quantum dots (BC3QDs). Results showed chemical activity values of -5.512 eV for nitrogen-doped and -3.971 eV for phosphorus-doped BC3QDs, with nitrogen-doped samples exhibiting higher chemical activity. Doping introduced mid-gap states, causing a red shift in the absorption spectra of 106 nm for nitrogen and 118 nm for phosphorus doping. Nitrogen doping (N-doping) enhanced charge transfer capabilities compared to phosphorus doping (P-doping). The nitrogen-doped BC3QDs also displayed HOMO and LUMO energy levels (-5.373 eV and -2.103 eV, respectively) that are closer to TiO2 and I−/I3−, making them more compatible for solar cell applications by increasing electron injection, fill factor, light collection efficiency, and open-circuit voltage. Despite an improved energy conversion potential, the N-doped BC3QDs’ efficiency (72.34%) was impacted by rapid non-radiative recombination. These insights can guide the design of BC3QDs in solar energy applications, photocatalytic devices, and QD nano-composites for energy harvesting.

Effect of ultra-thin ZnS passivation using ALD technique on the performance of heterojunction solar cells

Hybrid solar cells (HSCs) using poly (3,4-ethylenedioxy-thiophene) polystyrene sulfonate (PEDOT:PSS) and n-silicon provide heterojunctions with the potential of light trapping, cost effectiveness, and high efficiency. However, charge recombination at rear interface hampers built-in potential and power conversion efficiency (PCE). Here, a superior, conformal, and uniform ultra-thin layer of Zinc sulfide (ZnS) is deposited on rear interface using atomic layer deposition (ALD) technique. The ALD-deposited ZnS thin layer serves as a passivation, electron conductive, and hole-blocking layer. The optimized HSCs exhibit a remarkable PCE of 12.37 % alongside a high open-circuit voltage of 0.625 V and a substantial fill factor of 71.5 %. These advancements stem from enhanced back junction quality between n-Si and electrode. The outcomes demonstrate an effective suppression of charge recombination and enhanced charge transfer facilitated by ALD-deposited ZnS thin layer, resulting an improved photovoltaic performance.

Activation of peroxymonosulfate by MnOOH/g-C3N5: Study on highly selective removal of phenolic pollutants and its non-radical pathway

In this research, the MnOOH/g-C3N5 material was successfully synthesized, demonstrating its efficacy in selectively removing phenolic organic pollutants. This material outperformed traditional free radical pathways, exhibiting higher selectivity, enhanced persulfate utilization efficiency, and strong resistance to background anions and complex organic matter. Using phenol as the target pollutant, the MnOOH/g-C3N5/PMS system achieved 81 % mineralization, a PMS utilization efficiency of 88 %, and a 75 % process unit energy consumption value in degrading phenol. This efficient degradation is attributed to the synergistic effects of high-valence metal oxides (MnV(O)/MnIV(O)), singlet oxygen (1O2), and electron transfer complexes, as confirmed by electrochemical analysis and In-situ EPR. Additionally, Transmission Electron Microscopy observations disclosed the development of an amorphous shell on the MnOOH/g-C3N5 surface post-reaction. Electrochemical Impedance Spectroscopy analysis suggested an enhanced charge transfer resistance, further affirming the role of MnOOH/g-C3N5 as an "electron transfer station" in the electron transfer process, accompanied by the formation of electron transfer complexes. This study provides crucial scientific insights and theoretical guidance for applying MnOOH/g-C3N5 materials in environmental engineering.