Charge Transfer Pathway Research Articles

Efficient hierarchical ZIF-based electro/photocatalyst toward hydrogen generation and evolution

In this study, a well-designed hierarchical BiFeO3/ZIF-67 (BFO-ZIF) composite was successfully synthesized to improve the performance of photocatalytic hydrogen generation in comparison to bare BiFeO3 and ZIF-67. Moreover, the behavior of the resultant electrocatalysts was also investigated in the hydrogen evolution reaction (HER). The synthesized electro-photocatalysts were characterized by various physical and photo/electrochemical analyses. The remarkable outcomes of the composite with 50 wt% of ZIF-67 in hydrogen generation correspond to the high specific surface area of the photocatalyst concurrently with the formation of active sites and new charge channels, leading to a modified charge transfer pathway and lower electron-hole recombination. The maximum H2 generation rate over the optimal BFO-ZIF composite (BFO-ZIF(50)) attained 1617 μmol g−1 h−1 during visible light exposure, surpassing the rates observed for pure BFO and ZIF-67. Furthermore, the BFO-ZIF(50) electrocatalyst, with the onset potential of −0.089 V, resulted in an overpotential of −0.19 V at a current density of 10 mA cm−2, while a Tafel slope of 81.6 mV dec−1 in 1.0 M KOH showed the highest activity. The elevated photocatalytic hydrogen generation and improved HER performance of the developed catalysts signify a synergistic effect resulting from the junction and the Z-scheme charge transfer mechanism between the ZIF-67 and BFO nanomaterials. This introduces the BFO-ZIF composite as an efficient photocatalyst and electrocatalyst for hydrogen generation and evolution reaction.

Preparation of Wood-Based Carbon Quantum Dots and Promotion of Light Capture Applications

CQDs are a type of fluorescent nanocarbon material that possess excellent optical properties. They have a wide range of raw material sources, making them a versatile option for various applications. The use of fluorescent materials to enhance the solar energy capture capacity of chloroplasts has the potential to significantly improve natural photosynthesis. CQDs and N-CQDs were prepared from natural Salix wood powder using a simple, green, and environmentally friendly hydrothermal method. These materials can effectively capture ultraviolet (UV) light and were used for photosynthesis to enable chloroplasts to utilize UV light that cannot be absorbed by them. The chlorophyll content of leaves treated with CQDs and N-CQDs increased, with the N-CQDs 25 mg/L treated group showing a 35.6% increase compared to the untreated group. Additionally, the treatment of CQDs and N-CQDs positively affected the transfer of electrons from photosystem II, further enhancing photosynthetic activity. This study presents ideas for expanding the use of solar energy, optimizing the photosynthesis charge transfer pathway, and improving solar energy conversion efficiency.

Coupling Reliable Interfacial Carrier Migration Channels with Visible-Light Response Antennas in ZnO-Based Heterostructure for Ameliorated Photocatalytic Hydrogen Generation.

Engineering targeted and reliable charge transfer pathways in multiphase photocatalysts remains a challenge. Herein, we conceptualize the Cd@CdS-ZnO/reduced graphene oxide (rGO)/ZnS heterostructures coupled with reliable carrier migration channels and visible-light response antennas by building rGO-integrated electrochemical nanoreactors and an ion-exchange process. In this ternary catalyst, the Cd clusters and rGO perform as charge relays to boost carrier transport via the Z-scheme route and accelerate photogenerated carriers to react with surface-adsorbed substances. Meanwhile, thanks to CdS, the heterostructures have photocatalytic properties under visible light illumination and can also inhibit self-corrosion by shielding Cd clusters to avoid disrupting charge transfer channels. Therefore, the special heterostructure demonstrates fascinating photocatalytic hydrogen production activity without the intervention of cocatalysts. This work provides a feasible protocol for improving the interfaces between metals and semiconductors to achieve efficient photocatalytic hydrogen generation.

Comparative study of interfacial charge transfer at the junction between CuInS2:In2S3/g-C3N4 photocatalysts for sacrificial hydrogen evolution activity

The quest for sustainable and efficient renewable energy sources has escalated in recent years, with photocatalytic hydrogen production gaining prominence due to its potential to harness solar energy for clean fuel generation. In this study, we design 2D/2D heterostructure CuInS2:In2S3/g-C3N4 nanosheets utilizing electrostatic interaction for hydrogen evolution reaction under visible light irradiation. Integrating CuInS2:In2S3 and g-C3N4 layers to form an interfacial 2D:2D heterostructure results in a broad light absorption range, effective charge separation, and excellent stability. The heterostructure ensures efficient interfacial charge transfer pathways, mitigating electron-hole recombination and promoting hydrogen evolution. The hybrid nanosheets prepared with the hydrothermal method exhibited ∼40-fold synergistic enhancement in hydrogen production and long-term stability. The synergistic boost in activity resulted from the formation of S-scheme heterojunctions (CuInS2/g-C3N4 and CuInS2/In2S3) within hybrid nanosheets.

Heteroatom‐Doped Ag25 Nanoclusters Encapsulated in Metal–Organic Frameworks for Photocatalytic Hydrogen Production

AbstractAtomically precise metal nanoclusters (NCs) with unique optical properties and abundant catalytic sites are promising in photocatalysis. However, their light‐induced instability and the difficulty of utilizing the photogenerated carriers for photocatalysis pose significant challenges. Here, MAg24 (M=Ag, Pd, Pt, and Au) NCs doped with diverse single heteroatoms have been encapsulated in a metal–organic framework (MOF), UiO‐66‐NH2, affording MAg24@UiO‐66‐NH2. Strikingly, compared with Ag25@UiO‐66‐NH2, the MAg24@UiO‐66‐NH2 doped with heteroatom exhibits much enhanced activity in photocatalytic hydrogen production, among which AuAg24@UiO‐66‐NH2 presents the best activity up to 3.6 mmol g−1 h−1, far superior to all other counterparts. Moreover, they display excellent photocatalytic recyclability and stability. X‐ray photoelectron spectroscopy and ultrafast transient absorption spectroscopy demonstrate that MAg24 NCs encapsulated into the MOF create a favorable charge transfer pathway, similar to a Z‐scheme heterojunction, when exposed to visible light. This promotes charge separation, along with optimized Ag electronic state, which are responsible for the superior activity in photocatalytic hydrogen production.

Enhancement of low-temperature activity of γ-Fe2O3-modified V2O5-MoO3/TiO2 catalysts for selective catalytic reduction of NOx with NH3

In this study, a series of γ-Fe2O3-modified V2O5-MoO3/TiO2 (VMT) catalysts was prepared by wet impregnation method. The γ-Fe2O3-modified catalysts exhibited excellent catalytic performance, and 1.25 wt% γ-Fe2O3 content improved the deNOx efficiency at 150 °C from 54% (unmodified VMT catalyst) to 84% (modified catalyst). BET, XRD, XPS, NH3-TPD, H2-TPR, and in situ DRIFTs were employed to characterize the physicochemical properties and reaction mechanisms of the catalysts. The introduction of γ-Fe2O3 increased the V5+/V4+ ratio, surface chemisorbed oxygen content, redox ability, and a number of acid sites in the prepared catalysts. XPS confirmed the addition of γ-Fe2O3 introduced new charge transfer pathways (Fe3+/Fe2+ ↔ V5+/V4+). In situ DRIFTs suggested that the addition of γ-Fe2O3 to the catalyst significantly increased the adsorption capacity of catalyst for NH3 and NOx, while also exerting a strong activating effect on the adsorbed NH3. Furthermore, selective catalytic reduction over the VMT and 5PEG@1.25Fe-VMT catalysts followed the Eley-Rideal (E-R) mechanism. At temperatures above 200 °C, the 5PEG@1.25Fe-VMT catalyst also followed the Langmuir-Hinshelwood (L-H) mechanism.

Photocatalytic Generation of H2O2 Via a Hydrogen-Abstraction Pathway by Bi2.15WO6 under Visible Light.

Photocatalytic technology is a popular research area for converting solar energy into environmentally friendly chemicals and is considered the greenest approach for producing H2O2. However, the corresponding reactive oxygen species (ROS) and pathway involved in the photocatalytic generation of H2O2 by the Bi2.15WO6-glucose system are still not clear. Quenching experiments have established that neither •OH nor h+ contribute to the formation of H2O2, and show that the formed surface superoxo (≡Bi-OO•) and peroxo (≡Bi-OOH) species are the predominant ROS in H2O2 generation. In addition, various characterizations indicate the enhanced electron-transfer on the surface of Bi2.15WO6 with increasing contents of glucose via the ligand-to-metal charge transfer pathway, confirming H-transfer from glucose to ≡Bi-OO• or ≡Bi-OOH. The increased production of H2O2 with decreasing bond dissociation energy (BDEO-H) values of various phenolic compounds again supports the H-transfer mechanism from phenolic compounds to ≡Bi-OO• and then to ≡Bi-OOH. DFT calculations further reveal that on the Bi2.15WO6 surface, oxygen is sequentially reduced to ≡Bi-OO• and ≡Bi-OOH, while H-transfer from H2O or glucose to ≡Bi-OO• and ≡Bi-OOH, resulting in the production of H2O2. The lower energy barrier of H-transfer from adsorbed glucose (0.636 eV) than that from H2O (1.157 eV) indicates that H-transfer is more favorable from adsorbed glucose. This work gives new insight into the photocatalytic generation of H2O2 by Bi2.15WO6 in the presence of glucose/phenolic compounds via the H-abstraction pathway.

Optimizing construction of fern-like Co3O4@Ni3Fe-LDH p-n heterojunction for boosting photo-assisted-electronic N2 reduction into NH3 and DFT calculation

Herein, a fern-like p-n heterojunction by anchoring Ni3Fe-LDH nanoplates onto Co3O4 nanoneedles have been optionally constructed. Essentially, p-n heterojunction ensured to induce strong built-in electric field, and inherit interfacial electron redistribution. Based on their compatible and well-matched electronic band structures, a staggered type-II photo-generated electron/holes transfer pathway have been elaborated by density functional theory calculation (DFT), in situ irradiation X-ray photoelectron spectroscopy (XPS), and fluorescent decay. This band bending and charge migrating module conferred the architecture with strong redox ability, sufficient exciton dissociation, and admirable optoelectronic characteristics. Moreover, the heterostructure acquired broad absorption spectrum to exhibit outperforming photocatalytic effect. Totally, this electron redistribution at the hierarchical interface, a type-II scheme charge-transfer pathway and the oxygen defects would lead to high efficiency in solar light assisted N2 reduction. Typically, Co@Ni3Fe-2 catalyst exhibited the highest NH3 production rate of 16.15 μg h−1 mgcat.−1 and Faraday efficiency (FE) of 31.57% at −0.6 V vs. RHE in 0.1 M Na2SO4 solution. Fortunately, with light exposure, the NH3 production rate and FE could increase by 27.9% and 18.1% than that under dark. This work would provide a plausible attitude towards the design of high efficient photocatalyst for artificial photosynthesis with multi-functionalized coupling effect.

A triazine-based covalent organic framework decorated with cadmium sulfide for efficient photocatalytic hydrogen evolution from water

Construction of inorganic/organic heterostructures has been proven to be a very promising strategy to design highly efficient photocatalysts for solar driven hydrogen evolution from water. Herein, we report the preparation of a direct Z-scheme heterojunction photocatalyst by in situ growth of cadmium sulfide on a triazine-based covalent organic framework (COF). The triazine based-COF was synthesized by condensation reaction of precursors 1,3,5-tris-(4-formyl-phenyl) triazine (TFPT) and 2,5-bis-(3-hydroxypropoxy) terephthalohydrazide (DHTH), termed as TFPT-DHTH-COF. Widely distributed nitrogen atoms throughout TFPT-DHTH-COF skeletons serve as anchoring sites for strong interfacial interactions with CdS. The CdS/TFPT-DHTH-COF composite showed a hydrogen evolution rate of 15.75 mmol h−1 g−1, which is about 75 times higher than that of TFPT-DHTH-COF (0.21 mmol h−1 g−1) and 3.4 times higher than that of CdS (4.57 mmol h−1 g−1). With the properly staggered band alignment and strong interfacial interaction between TFPT-DHTH-COF and CdS, a Z-scheme charge transfer pathway is achieved. The mechanism has been systematically analyzed by steady state and time-resolved photoluminescence measurements as well as in situ irradiated X-ray photoelectron spectroscopy.

Ca-doping interfacial engineering and glycolysis enable rapid charge separation for efficient phototherapy of MRSA-infected wounds

Methicillin-resistant Staphylococcus aureus (MRSA) is the primary pathogenic agent responsible for epidermal wound infection and suppuration, seriously threatening the life and health of human beings. To address this fundamental challenge, we propose a heterojunction nanocomposite (Ca-CN/MnS) comprised of Ca-doped g-C3N4 and MnS for the therapy of MRSA-accompanied wounds. The Ca doping leads to a reduction in both the bandgap and the singlet state S1–triplet state T2 energy gap (ΔEST). The Ca doping also facilitates the two-photon excitation, thus remarkably promoting the separation and transfer of 808 nm near-infrared (NIR) light–triggered electron–hole pairs together with the built-in electric field. Thereby, the production of reactive oxygen species and heat are substantially augmented nearby the nanocomposite under 808 nm NIR light irradiation. Consequently, an impressive photocatalytic MRSA bactericidal efficiency of 99.98 ± 0.02 % is achieved following exposure to NIR light for 20 min. The introduction of biologically functional elements (Ca and Mn) can up-regulate proteins such as pyruvate kinase (PKM), L-lactate dehydrogenase (LDHA), and calcium/calmodulin-dependent protein kinase (CAMKII), trigger the glycolysis and calcium signaling pathway, promote cell proliferation, cellular metabolism, and angiogenesis, thereby expediting the wound-healing process. This heterojunction nanocomposite, with its precise charge-transfer pathway, represents a highly effective bactericidal and bioactive system for treating multidrug-resistant bacterial infections and accelerating tissue repair. Statement of significanceDue to the bacterial resistance, developing an antibiotic-free and highly effective bactericidal strategy to treat bacteria-infected wounds is critical. We have designed a heterojunction consisting of calcium doped g-C3N4 and MnS (Ca-CN/MnS) that can rapidly kill methicillin-resistant Staphylococcus aureus (MRSA) without damaging normal tissue through a synergistic effect of two-photon stimulated photothermal and photodynamic therapy. In addition, the release of trace amounts of biofunctional elements Mn and Ca triggers glycolysis and calcium signaling pathways that promote cellular metabolism and cell proliferation, contributing to tissue repair and wound healing.

Dual elemental doping activated signaling pathway of angiogenesis and defective heterojunction engineering for effective therapy of MRSA-infected wounds

Multi-drug resistant bacterial infections pose a significant threat to human health. Thus, the development of effective bactericidal strategies is a pressing concern. In this study, a ternary heterostructure (Zn–CN/P-GO/BiS) comprised of Zn-doped graphite phase carbon nitride (g-C3N4), phosphorous-doped graphene oxide (GO) and bismuth sulphide (Bi2S3) is constructed for efficiently treating methicillin-resistant Staphylococcus aureus (MRSA)-infected wound. Zn doping-induced defect sites in g-C3N4 results in a reduced band gap (ΔE) and a smaller energy gap (ΔEST) between the singlet state S1 and triplet state T1, which favours two-photon excitation and accelerates electron transfer. Furthermore, the formation of an internal electric field at the ternary heterogeneous interface optimizes the charge transfer pathway, inhibits the recombination of electron-hole pairs, improves the photodynamic effect of g-C3N4, and enhances its catalytic performance. Therefore, the Zn–CN/P-GO/BiS significantly augments the production of reactive oxygen species and heat under 808 nm NIR (0.67 W cm−2) irradiation, leading to the elimination of 99.60% ± 0.07% MRSA within 20 min. Additionally, the release of essential trace elements (Zn and P) promotes wound healing by activating hypoxia-inducible factor-1 (HIF-1) and peroxisome proliferator-activated receptors (PPAR) signaling pathways. This work provides unique insight into the rapid antibacterial applications of trace element doping and two-photon excitation.

Heteroatom-Doped Ag25 Nanoclusters Encapsulated in Metal-Organic Frameworks for Photocatalytic Hydrogen Production.

Atomically precise metal nanoclusters (NCs) with unique optical properties and abundant catalytic sites are promising in photocatalysis. However, their light-induced instability and the difficulty of utilizing the photogenerated carriers for photocatalysis pose significant challenges. Here, MAg24 (M=Ag, Pd, Pt, and Au) NCs doped with diverse single heteroatoms have been encapsulated in a metal-organic framework (MOF), UiO-66-NH2, affording MAg24@UiO-66-NH2. Strikingly, compared with Ag25@UiO-66-NH2, the MAg24@UiO-66-NH2 doped with heteroatom exhibits much enhanced activity in photocatalytic hydrogen production, among which AuAg24@UiO-66-NH2 presents the best activity up to 3.6 mmol g-1 h-1, far superior to all other counterparts. Moreover, they display excellent photocatalytic recyclability and stability. X-ray photoelectron spectroscopy and ultrafast transient absorption spectroscopy demonstrate that MAg24 NCs encapsulated into the MOF create a favorable charge transfer pathway, similar to a Z-scheme heterojunction, when exposed to visible light. This promotes charge separation, along with optimized Ag electronic state, which are responsible for the superior activity in photocatalytic hydrogen production.

Exploring the photoelectrochemical process through surface states of plasmonic Ag-loaded NiFe-LDH-modified CuWO4 photoanode

Optimizing the interfacial action of photoanode for photoelectrochemical (PEC) behavior to facilitate charge transport is essential for enhancing solar-to-fuel efficiency. Herein, a typical CuWO4/NiFe-LDH/Ag photoanode was reported and an alternative pathway for charge transfer in the PEC process through surface states mechanism was elucidated. In particular, the layer double hydroxides (NiFe-LDH) acted as charge-transfer agents to facilitate the transfer of photogenerated carriers; while the surface plasmon resonance (SPR) effect of the Ag provided hot electrons, which increased the carrier concentration and promoted the charge separation. The influence of presence of surface states on the PEC process was systematically illustrated. Experimental results indicated that the optimized CuWO4/NiFe-LDH/Ag photoanode displayed a photocurrent that was more than an order of magnitude larger than that of the pure CuWO4 (increasing from 0.30 mA cm−2 to 1.45 mA cm−2 at 1.23 V vs. RHE), accompanied by favorable electrochemical impedance and stability (maintaining 92.4%). Importantly, increasing the available filled surface states could be beneficial in enhancing the PEC behavior. This work provided additional insights into photoanode charge transport in PEC processes.

Interface-induced charge transfer pathway switching of a Cu2O-TiO2 photocatalyst from p-n to S-scheme heterojunction for effective photocatalytic H2 evolution

Photocatalytic hydrogen evolution from water splitting is an appealing method for producing clean chemical fuels. Cu2O, with a suitable bandgap, holds promise as a semiconductor for this process. However, the strong photo-corrosion and rapid charge recombination of Cu2O strongly limit its application in the photocatalytic fields. Herein, an S-scheme heterojunction photocatalyst composed of TiO2 and Cu2O was rationally designed to effectively avoid the photo-corrosion of Cu2O. The introduction of an interfacial nitrogen-doped carbon (NC) layer switches the heterojunction interfacial charge transfer pathway from the p-n to S-scheme heterojunction, which avoids excessive accumulation of photogenerated holes on the surface of Cu2O. Meanwhile, the hybrid structure shows a broad spectral response (300–800 nm) and efficient charge separation and transfer efficiency. Interestingly, the highest photocatalytic hydrogen evolution rate of TiO2-NC-3%Cu2O-3%Ni is 13521.9 μmol g−1 h−1, which is approximately 664.1 times higher than that of pure Cu2O. In-situ X-ray photoelectron spectroscopy and Kelvin probe confirm the charge transfer mechanism of S-scheme heterojunction. The formation of S-scheme heterojunctions effectively accelerates the separation of photogenerated electron-hole pairs and enhances redox capacity, thereby improving the photocatalytic performance and stability of Cu2O. This study provides valuable insights into the rational design of highly efficient Cu2O-based heterojunction photocatalysts for hydrogen production.

Flexible construction of heteroatom-free g-C3N4/g-C3N4 homojunction with switching charge dynamics toward efficient photo-piezocatalytic performance

Photo-piezocatalysis based on homojunction emerges as an auspicious approach for the environmental crisis, while it is still in early stage with limited strategies and ambiguous reaction mechanisms. Herein, a heteroatom-free homojunction of ultrathin g-C3N4 with N vacancies/pristine g-C3N4 has been innovatively constructed through surface coupling effect. It achieves higher performance on both photo-piezocatalytic RhB degradation and H2O2 production than solely piezocatalysis or photocatalysis. The underlying causes lie in the synergistic effects of the internal electric field constructed in the type II homojunction and the polarized electric field stimulated by the non-centrosymmetric structure, which cooperatively facilitate the driving force of the charge carriers. Notably, due to the unfixed polarization direction, the charge transfer pathways undergo transitions between type-II and Z-scheme mechanisms, which both promote the spatial separation and migration dynamics of electrons and holes. This work provides new insights into structural design and mechanism exploration for highly efficient photo-piezocatalytic applications.

Nanoflower-like TiO2/CoAl-layered double hydroxide direct Z-scheme for boosted photocatalytic CO2 conversion

Direct Z-scheme heterojunction (DZH) has promising potential in photocatalytic carbon dioxide reduction (PCR) owing to its unusual charge transfer pathway, exceptional charge separation efficiency, and high redox ability. Herein, ultrathin TiO2 nanosheets (NSs) have been employed as a substrate for the in-situ growth of CoAl layered double hydroxide (LDH) NSs to fabricate nanoflower-like TiO2/CoAl-LDH (TCA) DZH. The unconsolidated heterostructure is beneficial for active site exposure and mass transfer, and the inherent alkalinity of CoAl-LDH promoted the adsorption of CO2, synergistically boosting the process of PCR reaction in the TCA system. Simulated calculation and in-situ analysis jointly demonstrate the unique electron transfer processes during hybridization and photoexcitation. The resulting (-)TiO2/(+)CoAl-LDH interfacial electric field and DZH further lead to efficient separation of photogenerated charges of TCA. In the solid–gas system, the optimized TCA heterojunction exhibits a competitive PCR activity (76.18 μmol g−1h−1 for CO production rate) increase of 31.6 and 20.3 times compared to TiO2 and CoAl-LDH, respectively.

Graphene-decorated novel Z-scheme Bi@MOF composites promote high performance photocatalytic desulfurization

The Z-scheme photocatalyst constructed based on bismuth-based metal oxides (BMO) and metal–organic frameworks (MOF) holds significant potential for effectively degrading odorous Reduced Sulfur Compounds (RSC) due to its robust redox capabilities. However, challenges such as lattice mismatch, interface defects, and rapid recombination of photogenerated charges substantially impede the Z- scheme charge transfer in BMO@MOF photocatalysts. In this research, graphene was introduced into the BiVO4@NH2-UiO-66 system as an electron bridge and co-catalyst to reduce the interfacial transfer resistance and increase the absorption of near-infrared light, resulting in superior degradability of RSCs compared to both the individual components and BiVO4@NH2-UiO-66. The incorporated graphene not only serves as the growth substrate for BiVO4 and NH2-UiO-66 but also plays a crucial role as an electron mediator in enhancing the vectorial charge transfer from BiVO4 to NH2-UiO-66. This strengthens the Z-scheme charge transfer pathway, suppressing bulk charge recombination, increasing overall carrier density, and maintaining robust redox capabilities. Additionally, the investigation of active species and key intermediate products was conducted to explore potential degradation pathways of RSCs. This work demonstrates a novel approach in promoting photocatalytic degradation of RSCs by harnessing the synergistic effects between doping and heterogeneous structures within the photocatalyst.

Dual p-n Z-scheme heterostructure boosted superior photoreduction CO2 to CO, CH4 and C2H4 in In2S3/MnO2/BiOCl photocatalyst

The creation of a Z-scheme heterojunction is a sophisticated strategy to enhance photocatalytic efficiency. In our study, we synthesized an In2S3/MnO2/BiOCl dual Z-scheme heterostructure by growing BiOCl nanoplates on the sheets of In2S3 nanoflowers, situated on the surface of MnO2 nanowires. This synthesis involved a combination of hydrothermal and solution combustion methods. Experiments and density functional theory (DFT) calculations demonstrated that the In2S3/MnO2/BiOCl composite exhibited notable photo reduction performance and photocatalytic stability. This was attributed to the pivotal roles of BiOCl and MnO2 in the composite, acting as auxiliaries to enhance the electronic structure and facilitate the adsorption/activation capacity of CO2 and H2O. The yield rates of CO, CH4, and C2H4 over In2S3/MnO2/BiOCl as the catalyst were 3.94, 5.5, and 3.64 times higher than those of pure In2S3, respectively. Photoelectrochemical analysis revealed that the dual Z-scheme heterostructure, with its oxygen vacancies and large surface area, enhanced CO2 absorption and active sites on the nanoflower/nanowire intersurfaces. Consequently, the dual Z-scheme charge transfer pathway provided efficient channels for boosting electron transfer and charge separation, resulting in high C2H4, CH4, and CO yields of formed and exihibits an promising photoreduction rate of CO2 to CO (51.2 µmol/g.h), CH4 (42.4 µmol/g.h) and C2H4 (63.2 µmol/g.h), respectively. DFT, in situ Diffuse reflectance infrared fourier transform spectroscopy, and temperature-programmed desorption tests were employed to verify the intermediates pathway. The study proposed a potential photocatalytic mechanism based on these findings.

Constructing the Interconnected Charge Transfer Pathways in Sulfur Composite Cathode for All-Solid-State Lithium-Sulfur Batteries.

All-solid-state lithium-sulfur batteries (ASSLSBs) have advantageous features, such as high energy, low costs, enhanced safety, and no polysulfide dissolution. However, the use of sulfur as an active material in all-solid-state batteries is difficult because of its ionic and electrical insulating properties. Herein, we introduce a flower-shaped composite material consisting of MoS2 nanoparticles and sulfur, designed to establish interconnected ionic and electrical conduction pathways at the cathode. As a host material, MoS2 nanoparticles with a large specific surface area can coconduct Li ions and electrons, possessing the potential for effectively utilizing sulfur. However, MoS2 nanoparticles are prone to physical-electrochemical isolation by being surrounded by sulfur due to their crumpling property in the process of mixing and impregnation with sulfur. This problem is addressed by mildly milling the MoS2 nanoparticles and sulfur, after which melt diffusion is applied to generate uniform MoS2/sulfur composite materials to establish an interconnected conducting pathway within the composite. A sulfide solid electrolyte (Li6PS5Cl)-based ASSLSB incorporating the proposed MoS2/sulfur composite demonstrates a stable operation over 1000 cycles with a Coulombic efficiency of nearly 100%. This study emphasizes the significance of the structural design of the sulfur composite material on top of the intrinsic properties of the material for high-performance ASSLSBs.

Interfacial electric field competition in strain-modulated MoSTe/Hf2CO2: Inducing a direct-Z scheme charge transfer pathway for overall water splitting

The key to high-performance photocatalysts is efficient charge separation and easy regulation. A two-dimensional (2D) MoSTe/Hf2CO2 heterojunction has been proposed using density-functional theory (DFT), and the charge transfer path of the direct-Z scheme has been realized in the presence of strain. Importantly, the MoSTe/Hf2CO2, with its abundant tunability, is able to effectuate the transition from Type–II–A → Type-I → Type–II–B → direct Z-scheme → Type-III. In particular, under +2% and +3% biaxial strains, the band gaps of MoSTe/Hf2CO2 heterojunction are 0.335 and 0.024 eV, respectively, smaller than those of conduction band offset (CBO) and valence band offset (VBO), which favors the recombination of interlayer carriers and thus the formation of direct Z-scheme heterojunctions. While the charge transfer at the interface is subjected to two interfacial electric fields (IEF), IEFMoSTe and IEFInterface, which have obvious competition, the tensile strain leads to the enhancement of the interlayer coupling, which in turn strengthens the competitive advantage of the IEFInterface of the heterojunction. Moreover, the Gibbs free energy in hydrogen evolution reaction (HER) of the MoSTe/Hf2CO2 at a strain of +3% is very near to 0, meeting the requirements for an ideal photocatalyst. In this study, not only is a high-performance direct-Z scheme photocatalyst that can undergo overall water splitting proposed but also the abundant tunability of this heterojunction will have great application prospects in optoelectronic devices.