Strong Built-in Electric Field Research Articles

Overall photosynthesis of hydrogen peroxide with redox-active catechol moiety by modulating charge behavior of polydopamine-coated engineered carbon nitride

Photocatalytic production of hydrogen peroxide (H2O2) offers an environment-friendly and sustainable route. However, low efficiency and undesirable by-products hinder its large-scale application. A heterostructure (PDA/SCN) by in situ polymerization dopamine on edge functionalized carbon nitride (SCN) has been designed to integrate photoredox and photocatalytic production of hydrogen peroxide with revisable transformation between catechol and o‑benzoquinone. Benefiting from the strong built-in electric field, efficient photoinduced charge separation is disclosed to facilitate the autoxidation of redox-active catechol moiety. In addition, functional groups (–NH2) on the heterostructure, as an interfacial H-bond modulation site, are conductive to optimize the O2 activation and subsequent formation of the key intermediate *OO. Moreover, a homemade gas-solid-liquid triphase flow cell using PDA/SCN photocatalyst with improving mass transfer process has been constructed, which shows a high H2O2 generation of 1.32 mM h–1 under visible light (λ ≥ 420 nm) without using any sacrificial reagent. This photocatalytic system provides a new guidance of efficient photocatalyst design for the synthesis of H2O2 without using any sacrificial reagent.

Construction of a MoOx/MoS2 Heterojunction via the Surface Sulfurization of the Oxide and Its Photocurrent-Switching Characteristics in the Range of the Broadband Light Spectrum.

In order to utilize the longer wavelength light, the surface sulfurization of MoO3 was carried out. The photocurrent responses to typical 650, 808, 980, and 1064 nm light sources with Au gap electrodes were investigated. The results showed that the surface S-O exchange of MoO3 improved the interfacial charge transfer in the range of the broadband light spectrum. The S and O can be exchanged on the surface of MoO3 nanosheets under the hydrothermal condition, leading to the formation of a surface MoOx/MoS2 heterojunction. The interfacial interaction between the MoO3 nanosheets and MoS2 easily generated free electrons and holes, and it effectively avoided the recombination of photogenerated carriers. Meanwhile, the surface S-doping of MoO3 also resulted in the generation of an oxygen vacancy and sulfur vacancy on MoO3-xS2-y. The plasmonic characteristics of MoO3-x contributed to the enhancement of the interfacial charge transfer by photoexcitation. Otherwise, even with zero bias applied, a good photoelectric signal was still obtained with polyimide film substrates and carbon electrodes. This indicates that the formation of the heterojunction generates a strong built-in electric field that drives the photogenerated carrier transport, which can be self-powered. This study provides a simple and low-cost method for the surface functionalization of some metal oxides with a wide bandgap.

Elucidating the dominant role of all-amorphous heterostructure on optimized built-in electric field with abundant active sites for advanced lithium–sulfur batteries

While various transition metal compound-based electrocatalysts have been developed to mitigate the shuttle effect of lithium–sulfur (Li–S) batteries, few studies have examined the effectiveness of their crystal structures. Herein, by integrating amorphous MoS2 nanosheets and TiO2 layers, an all-amorphous heterostructure is designed as a multifunctional electrocatalyst. The highly disordered atomic arrangement of the components provides abundant active sites and creates additional energy levels within the band gaps. Moreover, this unique crystal structures shift the Fermi level. Due to these synergistic effects, a well-aligned strong built-in electric field is generated, thereby exhibiting specific capacity of 1135 mA h g–1 at a current rate of 1 C, along with a stable long-term lifespan of 500 cycles at 2 C. This work provides a novel strategy for optimizing built-in electric field and amplifying active sites by constructing an all-amorphous heterostructure, which is crucial for the advanced Li–S batteries.

Fabrication and Mechanism Insight of Multidimensional Coupled Metal-Free van der Waals Heterostructures for Enhanced Photocatalytic Hydrogen Evolution.

It is an arduous issue to significantly improve the charge separation efficiency of polymer photocatalysts due to their inherently high exciton binding energy. Herein, based on an interfacial coupling and atom diffusion strategy, a metal-free 3D/2D van der Waals (VdW) heterojunction is fabricated through the modification of rich-vacancy wrinkle-like S8 (Vs-S8) microspheres on the surface of S-doped polymeric carbon nitride (S-PCN) nanosheets. The insight into the mechanism reveals that the interfacial coupling effect induces a strong built-in electric field from S-PCN to Vs-S8, and the carrier transfer behavior abides by the type-II charge transfer pathway, thereby dramatically improving the separation efficiency and transport kinetics of photogenerated carriers. As a result, the as-prepared metal-free 3D/2D Vs-S8/S-PCN VdW heterojunction is endowed with more superior photocatalytic hydrogen evolution (PHE) performance than PCN. The highest average PHE rate is about 11.3 times higher than that of PCN, and the apparent quantum efficiency reaches 30.1% at 400 nm on the optimal 3%-Vs-S8/S-PCN sample. This work contributes a new design strategy for a metal-free VdW heterojunction and provides a feasible avenue for improving the carrier separation efficiency of polymer photocatalysts.

Wafer-Scale Semitransparent MoS2/WS2 Heterojunction Catalyst on a Silicon Photocathode for Efficient Hydrogen Evolution.

The development of catalysts that are optically transparent, electrically charge-transferable, and capable of protecting underlying photoactive semiconductors is crucial for efficient photoelectrochemical (PEC) hydrogen production. However, meeting all these requirements simultaneously poses significant challenges. In this study, the fabrication of a wafer-scale transparent bilayer MoS2/WS2 catalyst is presented with a staggered heterojunction, optimized for photon absorption, extraction of photogenerated charge carriers, and surface passivation of p-Si photocathode. The MoS2 and WS2 monolayers are grown via metal-organic chemical vapor deposition, followed by sequential transfer and stacking onto the p-Si photocathode. The resulting type-II heterojunction film establishes a strong built-in electric field for rapid charge carrier transport and effectively protects the Si surface from oxidation and corrosion. The fabricated MoS2/WS2/p-Si photocathode demonstrates outstanding PEC performance, achieving a high photocurrent density of -25mAcm-2 at 0V versus reversible hydrogen electrode, along with enhanced stability compared to monolayer MoS2/p-Si. This work provides promising strategies for developing optically transparent, electrically active, and protective catalysts for practical PEC energy conversion systems.

Oxygen vacancy and boron dual sites enable efficient oxygen activation for emerging contaminant degradation: Boosted exciton dissociation via built-in electric field modulation

Two-dimensional (2D) layered materials are promising photocatalysts for environmental remediation through O2 activation. However, the inherent robust excitonic effects from the confined-layer structure hinder the generation of highly oxidative free radicals from the preferred charge transfer pathway. Taking 2D BiOBr as a prototype, we implemented a superficial surface boronizing method to incorporate oxygen vacancy (OV)-boron (B) dual sites onto the surface. The OV-B dual sites disorder the surface atomic arrangement of BiOBr and induce strong built-in electric field (BEF). This effectively weakens exciton binding energy, boosts exciton dissociation into free charges, and facilities the transfer and separation of free charges, which collectively enables charge transfer to surpass excitonic effects as the dominant O2 activation pathway. Consequently, BiOBr with OV-B dual sites outperforms pristine and mono-OV modified BiOBr in both O2 activation and emerging contaminant degradation. This work offers insightful strategies for modulating 2D photocatalysts to optimize O2 activation towards efficient contaminant removal.

Co/CoTe heterostructure internal hairy fibers as high-efficiency oxygen electrocatalyst for Zn-air batteries

The design of highly efficient catalysts to enhance the kinetics of oxygen reduction (OER) and oxygen evolution (ORR) reactions is the key issue for the development of high-performance Zn-air battery. In this work, we report the design of Co-CoTe heterostructured fibers as the bifunctional oxygen catalyst for Zn-air battery. Firstly, the theoretical analysis was carried out on Co-CoTe heterostructure. The large work function difference is favorable to construct strong interfacial built-in electric field (BIEF), and the low energy barrier endows high catalytic activities. Moreover, the in-situ grown carbon shell was designed to build “core–shell” Co-CoTe/C unit to realize its high performance. They assemble the Co-CoTe@HFS fiber with good self-supporting and flexible features. Taken the advantages of the strong BIEF, the “core–shell” basic unit, and the freestanding substrate, the Co-CoTe@HFS fiber achieves the good electrocatalytic properties and high reliability. The full Zn-air battery (ZAB) with the Co/CoTe@HFS air cathode achieves the high peak power density and cycling stability over long-term cycling. Therefore, this work provides a clue to design bifunctional oxygen catalysts for high-performance ZABs.

Heterophase hexagonal/orthorhombic molybdenum trioxide nanorods for photocatalytic hydrogen production

Phase engineering plays a critical role in enhancing photocatalytic performance of metal oxides. Herein, we demonstrate the phase-selective synthesis of MoO3 (hexagonal h-MoO3, orthorhombic α-MoO3, and their junction h/α-MoO3) through controlled phase transitions by adjusting annealing conditions. As evidenced with photocatalytic hydrogen evolution reaction, h/α-MoO3 (14.20 μmol/h) phase junction shows superior performance to either h-MoO3 (9.62 μmol/h) or α-MoO3 (11.31 μmol/h), with a hydrogen yield of 47.6% and 25.6% greater than that of h-MoO3 and α-MoO3 (Pt as cocatalyst), respectively. A systematic study of the chemical structure characterizations, photochemical tests, band structure analysis, and photocatalytic activity evaluation reveal that, the enhancement is attributed to the strong built-in electric field in the h/α-MoO3 phase junction, which effectively facilitates charge separation. Our findings introduce a novel strategy for improving photocatalytic performance using phase engineering.

Atmosphere engineering of metal-free Te/C3N4 p-n heterojunction for nearly 100% photocatalytic converting CO2 to CO

Carbon nitride (CN)-based heterojunction photocatalysts hold promise for efficient carbon dioxide (CO2) reduction. However, suboptimal production yields and limited selectivity in CO2 conversion pose significant barriers to achieving efficient CO2 conversion. Here, we present the construction of a p-n heterojunction between ultrasmall Te NPs and CN nanosheet using a novel tandem hydrothermal-calcination synthesis strategy. Through ammonia-assisted calcination, ultrasmall Te NPs are grown in-situ on the CN nanosheets’ surface, resulting in the generation of a robust p-n heterojunction. The synthesized heterojunction exhibits increased specific surface area, reinforced visible light absorption, intensive CO2 adsorption capacity, and efficient charge transfer. The optimum Te/CN-NH3 demonstrates superior photocatalytic CO2 reduction activity and durability, with nearly 100 ​% selectivity for CO and a yield as high as 92.0 ​μmol ​g−1 ​h−1, a fourfold increase compared to pure CN. Experimental and theoretical calculations unravel that the strong built-in electric field of the Te/CN-NH3 p-n heterojunction accelerates the migration of photogenerated electrons from Te NPs to the N site on CN nanosheets, thereby promoting CO2 reduction. This study provides a promising material design approach for the construction of high-performance p-n heterojunction photocatalysts.

Understanding oxidation potential and degradation mechanism of acid-treated TiO2 coupled g-C3N4 S-scheme heterojunction photocatalyst for the removal of gaseous formaldehyde

In this work, a step (S)-scheme heterojunction catalyst is synthesized by coupling acid-treated TiO2 (ATT) with graphitic carbon nitride nanosheet (g-C3N4: GCN) and used for adsorption-photocatalytic removal of gaseous formaldehyde (FA: 100 - 500 ppm). The acid treatment of TiO2 proves to be an effective approach for improving the surface porosity of ATT with more abundant active sites for efficient catalytic reactions. Similarly, the S-scheme heterojunction displays superior redox potential (i.e., availability of free e- at conduction band of GCN (reduction potential of −0.485 eV/NHE) and free h+ at valance band of ATT (oxidation potential 2.79 eV/NHE)). As such, in a dynamic packed-bed flow reactor, the improved textural and optical properties of ATT-GCN (bed mass = 10 mg) offer outstanding adsorption and photocatalytic oxidation potential, effectively removing 86% of 200 ppm FA vapor at a reaction rate of 70.2 nmole mg−1 min−1 under slightly humidified conditions (e.g., 20% relative humidity (RH) and 21% O2) when exposed to 32-W UV-A light source. Under these operational conditions, the ATT-GCN achieves the superior performance metrics (e.g., quantum yield of 5.1E-02 molec. photon-1, space–time yield of 5.1E-03 molec. photon-1 mg−1, and specific clean air delivery rate of 515.4 L g-1 h−1). In-situ Kelvin probe microscope analysis of ATT-GCN postulates the formation of a strong built-in electric field to improve the separation of charge carriers. Considerations on the degradation pathway and intermediate dynamics with the aid of in-situ DRIFTS analysis suggest that the presence of water molecules (e.g., 20% RH) is beneficial for accelerating the oxidation and mineralization of FA molecules relative to a dry gas stream. The overall outcomes of this work are expected to help deliver new paths for the construction of advanced photocatalytic systems for upscaled applications toward air quality management.

Dual boosting of the built-in polarization field in the BiFeO3/ZnS heterostructure for water purification: Effects of Z-scheme heterostructure and corona poling

In this study, we have designed a novel 1D-0D lead-free Z-scheme heterostructure of BiFeO3–ZnS (BFO/ZnS) using an isoelectric point-assistant annealing method for piezocatalytic reactions. The open circuit voltage measurements exhibited a greater internal electric field for BFO/ZnS (90/10) than for individual components, causing its excellent piezocatalytic performance for MTZ antibiotics, organic dyes oxidation, and Cr(VI) reduction. BFO/ZnS (90/10) was treated by corona poling to boost its polarization, resulting in the highest remanent polarization and dielectric constant. Piezocatalytic experiments demonstrated that BFO/ZnS (90/10; poled) can degrade 99% of RhB by 9 min ultrasonic vibration with kapp = 0.44 min−1, which is 2.5, 5.5, and 16.3 times greater than those of BFO/ZnS (90/10), BFO, and ZnS, respectively. Also, the efficiency of piezodegradation for MTZ, Cr(VI), MO, and MB over BFO/ZnS (90/10; poled) was found to be 74.5% (90 min), 84.6% (60 min), 95.3% (40 min), and 97.2% (30 min), respectively. This outstanding piezocatalytic performance of BFO/ZnS (90/10; poled) is ascribed to the enhanced built-in polarization field due to the Z-scheme heterostructure and corona poling treatment. As supported by PL and EIS analysis, the stronger built-in electric field can effectively separate and transmit the charge carriers, causing excellent piezocatalytic activity.

Efficient hole extraction to reactive oxidation sites over a Co3O4/Cs3Sb2Br9 p-n heterojunction for enhanced benzylic C(sp3)-H bond oxidation

Photocatalytic selective oxidation of aromatic hydrocarbons plays an important role in the production of value-added chemicals. A key step in this process is the activation of C(sp3)-H bond by photogenerated holes. However, the inadequate hole generation and lack of surface adsorption-activation sites severely hinders the improvement in photocatalytic C-H bond oxidation. In particular, the random charge migration to the surface impedes the effective capture of holes by surface active sites to dissociate the C(sp3)-H bond. Here, we design and fabricate a Co3O4/Cs3Sb2Br9 p-n heterojunction that effectively addresses these challenges. The p-n heterojunction forms strong built-in electric fields (BEF) facilitating spatial charge separation. Holes are accumulated on Co3O4, while electrons are accumulated on Cs3Sb2Br9, thereby offering abundant active holes and electrons. Moreover, Co3O4 shows stronger adsorption and activation capacity for the C(sp³)-H bond, enabling the C(sp3)-H bond dissociation with low reaction energy barrier. Consequently, the holes are directionally extracted from photoactive Cs3Sb2Br9 to catalytically active Co3O4 under visible light irradiation, thereby accelerating the toluene oxidation. The optimized 5 % Co3O4/Cs3Sb2Br9 exhibits a benzyl aldehyde (BAD) evolution rate of 5044 μmol g−1 h−1 and a benzyl alcohol (BA) production rate of 1820 μmol g−1 h−1, which are 12 and 17 times higher than that of blank Cs3Sb2Br9, respectively.

Interfacial chemical bonds and sulfur vacancies synergistically modulated charge transfer in ZnIn2S4/MoO2-C Ohmic-junction photocatalyst for efficient hydrogen evolution

The construction of an Ohmic contact with a strong built-in electric field is crucial for the photocatalytic hydrogen evolution performance. However, consciously modulating Ohmic contacts to facilitate charge transfer remains very difficult. Herein, a sulfur vacancies-rich ZnIn2S4/MoO2-C Ohmic contact structure was synthesized by solvothermal method. Experimental results and DFT calculations indicated that the structure of MoO2-C changes under high temperature and pressure conditions, leading to the formation of interfacial Mo-S bonds with sulfur-vacancy-rich ZnIn2S4 in close contact. Importantly, the electronic structure of the Ohmic junction was synergistically modulated by interfacial chemical bonds and sulfur vacancies, creating a strong built-in electric field that effectively facilitated charge transfer and exciton dissociation at the interface. The optimized ZnIn2S4/MoO2-C composite exhibited a photocatalytic hydrogen evolution rate of 59.9 µmol h−1, which was 12 times and 4.7 times higher than that of ZnIn2S4 without sulfur vacancies and with sulfur vacancies, respectively. This work presented a novel method of synergistically modulating charge transfer in Ohmic junctions, promising improved photocatalytic performance.

Multiple enhancement effects of dipoles within polyimide cathode promoting highly efficient energy storage of lithium-ion batteries

Polyimide (PI) has been recognized as a potential organic cathode for Li-ion batteries (LIBs) due to its programmable structural design, high theoretical capacity, and resource availability. However, the poor intrinsic electrical conductivity of PI means that PI-based cathodes of LIBs have inefficient energy storage performance, especially at high current densities. In this work, the molecular structure of PI is optimized to obtain a layer-stacked crystalline PI with significantly enhanced dipoles, denoted NT-B for the first time. The dipoles in this PI are induced by the electronegative carbonyl groups from the monomer biuret and further enhanced via a π-π layer stacking effect. This work is the first to verify that the co-directional dipole enhancement effect of biuret is surprisingly different from that of monomer urea. A series of ex-situ/in-situ and theoretical DFT simulations are carried out to understand the functional mechanism of such effects. The multiple enhancement effects of the dipoles synergistically promoting the generation of a strong built-in electric field (BIEF) within NT-B are proposed based on the results obtained. It is confirmed that this BIEF plays a significant role in accelerating electron transport, which enhances the electrochemical activity of LIB cathodes. This work provides a new idea for the structural design of high-performance PI cathodes for LIBs.

Theoretical Study on Photocatalytic Reduction of CO2 on Anatase/Rutile Mixed-Phase TiO2.

The construction of anatase/rutile heterojunctions in TiO2 is an effective way of improving the CO2 photoreduction activity. Yet, the origin of the superior photocatalytic performance is still unclear. To solve this issue, the band edges between anatase and rutile phases were theoretically determined based on the three-phase atomic model of (112)A/II/(101)R, and simultaneously the CO2 reduction processes were meticulously investigated. Our calculations show that photogenerated holes can move readily from anatase to rutile via the thin intermediated II phase, while photoelectrons flowing in the opposite direction may be impeded due to the electron trapping sites at the II phase. However, the large potential drop across the anatase/rutile interface and the strong built-in electric field can provide an effective driving force for photoelectrons' migration to anatase. In addition, the II phase can better enhance the solar light utilization of (112)A/(100)II, including a wide light response range and an intensive optical absorption coefficient. Meanwhile, the mixed-phase TiO2 possesses negligible hydrogenation energy (CO2 to COOH*) and lower rate-limiting energy (HCOOH* to HCO*), which greatly facilitate CH3OH generation. The efficient charge separation, strengthened light absorption, and facile CO2 reduction successfully demonstrate that the anatase/rutile mixed-phase TiO2 is an efficient photocatalyst utilized for CO2 conversion.

Engineering MOF@LDH heterojunction with strong interfacial built-in electric field towards enhanced electrocatalytic water oxidation

Guiding the dynamic reconstruction of the oxygen evolution reaction (OER) is crucial for realizing the industrial application of hydrogen production through water electrolysis. In this study, we have intricately designed a built-in electric field (BIEF) between MIL-88B(Fe) and layered double hydroxide (LDH) with an adjusted work function difference. This design drives an asymmetric interfacial electron distribution, enhancing electron accumulation at the Fe sites within MIL-88B(Fe) and electron-deficient LDHs. Consequently, this setup promotes the surface dynamic reconstruction of LDHs into highly active oxyhydroxides, while simultaneously slowing down the rapid dissolution of Fe during OER operation. This optimization improves the adsorption/desorption of oxygen intermediates, ensuring a sustained high OER activity during long-term electrochemical operation. As expected, the optimal MIL-88B(Fe)@NiCo LDH configuration demonstrates a remarkably low overpotential of only 279 mV at 10 mA cm−2, maintaining operational stability for 70 h. This research significantly advances our understanding of the dynamic reconstruction of MOF@LDH heterojunctions and introduces a straightforward strategy for engineering BIEF to guide this process effectively.

Co-CoSe heterogeneous fibers with strong interfacial built-in electric field as bifunctional electrocatalyst for high-performance Zn-air battery

The explorations of efficient electrocatalysts to accelerate oxygen reactions in a wide temperature range is a crucial issue to the development of zinc-air batteries (ZAB) for all-climate applications. Herein, the Co-CoSe heterogeneous furry fibers (Co-CoSe@NHF) are developed as a bifunctional oxygen electrocatalyst for ZAB towards wide-temperature range applications. The Co-CoSe heterostructure with large work function difference (ΔWF) endows interfacial electron redistribution, which builds strong interfacial built-in electric field (BIEF) and improves the oxygen reactions. Meanwhile, the Co-CoSe heterostructure is encapsulated by in-situ grown carbon nanotubes, and forms the hollow fiber (NHF) with furry surface and beads-on-string configuration. The highly porous and conductive NHF configuration facilitates the fast kinetics and favors to accommodates volume change during cycling. As a result, the Co-CoSe@NHF achieves the superior bifunctional properties and good reliability for oxygen reactions. Integrated with the Co-CoSe@NHF fiber, the ZAB cell delivers the superior power density (301 mW cm−2) and long-term cycling stability over 280 h at 25 °C, and maintains the power densities of 126 mW cm−2 even the temperature decreases to −25 °C. Moreover, the solid-state ZAB exhibits significant flexibility and superior properties in a wide temperature range. Therefore, this work not only proposes a new strategy to design the high-performance bifunctional electrocatalysts, but also propels the development of flexible power sources for all-climate applications.

Z-scheme metal organic framework/Ag@AgCl heterojunction photocatalysts with elevated photocatalytic N2 fixation activity

As one of the most consumed chemical reagents, ammonia (NH3) has a wide range of applications in many fields. The demand for ammonia may continue to increase with the advancement of technology and the acceleration of industrialization. The traditional high energy consumption and high pollution ammonia synthesis methods (Haber-Bosch) need to be optimized and improved to reduce environmental pollution and energy dependence. In this work, a series of Z-scheme NM/Ag@AgCl heterojunctions were prepared as catalysts for the research of photocatalytic nitrogen fixation. By in-situ photodeposition, Ag@AgCl was uniformly distributed on the NM surface, and the interfaces of different substances were tightly bonded. The SPR effect that generated by Ag nanoparticles significantly enhanced the light energy absorption performance of heterojunction materials. In the ESR spectra, the signal peak intensity of NM/Ag@AgCl was higher than that of NM under light condition. Constructing of heterojunction was beneficial to the formation of Ti3+. The strong built-in electric field among NM and AgCl promoted the generation of Z-scheme heterojunction. NM/Ag@AgCl had sufficient redox potential to overcome thermodynamic barriers and drive the catalytic reaction. Without adding any sacrificial reagent, the ammonia production of NM/Ag@AgCl-3 reached 76.7 µmol g−1 h−1 under full spectrum radiation. The rate of ammonia formation of NM/Ag@AgCl was almost seven times than that of NM. The synergistic effect between NM and Ag@AgCl optimized the photogenerated carrier separation path. This work provided a new vision for the practical application of efficient photocatalytic N2 reduction.

Novel furan-containing linear polymer with strong built-in electric field for H2O2 photosynthesis

Using oxygen and water as raw materials, the photocatalytic production of H2O2 is a promising pathway. However, the limited charge separation efficiency represents a significant challenge in the photocatalysis field, as it impedes the generation of H2O2. Herein, a novel highly crystalline linear polymer has been synthesized here by bridging the strongly electronegative furan group with a diphenyl group, in order to adjust its molecular dipole moment to construct an intrinsic electric field to optimize photocatalytic performance. The optimal sample exhibited the best H2O2 synthesis rate of 2686 μmol·g−1·h−1 under pure water conditions, which is the best-performing linear conjugated polymer reported to date for H2O2 photosynthesis system. Importantly, the large internal dipole moment within furan-diphenyl linear polymer, together with the ordered crystalline structure induced robust built-in electric field, can facilitate migration and separation of photogenerated charge carriers. Manipulating molecular dipoles to enhance the built-in electric field can significantly improve photocatalytic activity, providing a new perspective for the rational design of functional linear conjugated polymers in green chemistry and sustainable production.

Electron Tandem Transport Channel in a Cu3P/Sv-ZnIn2S4 p-n Heterojunction for Photothermal-Photocatalytic Benzyl Alcohol Oxidation and H2 Production.

The development of photocatalytic systems with an electron tandem transport channel represents a promising avenue for improving the utilization of photogenerated electrons and holes despite encountering significant challenges. In this study, ZnIn2S4 (Sv-ZIS) with sulfur vacancies was fabricated using a solvothermal technique to create defect energy levels. Subsequently, Cu3P nanoparticles were coupled onto the surface of Sv-ZIS, forming a Cu3P/Sv-ZIS p-n heterojunction with an electron tandem transport channel. Experimental findings demonstrated that this tandem transport channel enhanced the carrier lifetime and separation efficiency. In addition, mechanistic investigations unveiled the formation of a robust built-in electric field (BEF) at the interface between Cu3P and Sv-ZIS, providing a driving force for electron migration. The combined consequences of the transport channel, the strong BEF, and photothermal effect led to a surface carrier separation efficiency of 65.85%. Consequently, Cu3P/Sv-ZIS achieved simultaneous H2 yield and benzaldehyde production rates of 18,101.4 and 15,012.6 μmol·g-1·h-1, which were 2.31 and 2.62 times higher than those of ZnIn2S4, respectively. This work exemplifies the design of the p-n heterojunction for the efficient utilization of photogenerated electrons and holes.