Bulk Modification Research Articles

Synergistic Passivation of Bulk and Interfacial Defects Improves Efficiency and Stability of Inverted Perovskite Solar Cells

Defects both in bulk and at the interfaces serve as charge trapping sites for nonradiative recombination and as ion migration pathways, resulting in degradation of perovskite solar cell efficiency and stability. In this work, a strategy for simultaneous passivation of both bulk and interfacial defects is reported. For bulk passivation polystyrene (PS) is used as an additive in the perovskite precursor which reduces the structural defects by forming larger defect‐free grains. While the F‐PEAI cation is used to passivate the interfacial defects, present at both perovskite HTL/ETL interfaces. Furthermore, by conducting control measurements with just bulk modification (PS), just interface modification (F‐PEAI), and a combination of both, the role of individual defect passivation strategies is decoupled. As a result of simultaneous bulk as well as interfacial passivation, the modified perovskite solar cell shows the highest efficiency of 22.32% with a high Voc of 1.14 V and fill factor of 80%. Moreover, the cells have excellent stability retaining 92% and 99% of their initial efficiency after 1008 h and 560 h under ISOS‐ D1 and D2 storage conditions. These results highlight the importance of simultaneous bulk and interfacial passivation for improving solar cell efficiency and stability.

Microfluidic capillary platform with hydrophilic PDMS for point-of-care immunoassays

Point-of-care (PoC) devices offer the possibility of fast and easy to use testing platforms. Self-driven capillary devices are particularly interesting because they can function without external pumps. Microfluidic devices often rely on polydimethylsiloxane (PDMS) prototyping; however, for self-driven microfluidics, its hydrophobic nature makes its use challenging. Bulk modification of PDMS through copolymers with hydrophilic moieties could be a practical solution because the copolymer is added prior to PDMS baking in a single-step process. In this work, a PDMS bulk modification with dimethylsiloxane-(60–70 % ethylene oxide) block copolymer was used to render PDMS hydrophilic. The addition of 1 % (w/w) copolymer resulted in a hydrophilic PDMS which was then used to fabricate the capillary devices. The microfluidic design included a serpentine channel with reagent entry points connected to a capillary pump and was closed by a membrane layer with conical shaped reservoirs. The reservoirs were designed to allow the sequential entry of the solutions and the device sealing and robustness were improved through PMMA frames with integrated magnets. A proof-of-concept was performed with food colouring demonstrating the capability of the device to flow the solutions sequentially. Finally, an immunoassay to detect the presence of Infliximab, a therapeutic antibody for chronic inflammatory diseases, was used to demonstrate the functionality of the capillary device. The versatility of the device was also shown by performing a fluorescent indirect immunoassay and a colorimetric indirect-ELISA for the detection of Infliximab with both approaches detecting Infliximab in the clinical range of interest (between 3 and 7 μg/mL).

Electrochemically Intercalated Ti3C2 MXene Bulk for Expanding Interlayer Spacing and Enhancing Supercapacitor Performance.

Tuning the interlayer spacing of 2D MXenes bulk mainly focuses on hydrothermal intercalation, physiotherapy intercalation, and ion exchange intercalation. Nevertheless, the feasibility of electrochemical intercalation technology for expanding the interlayer spacing of Ti3C2 MXene bulk is not yet clear, and further research is required to advance it. Here, we employed an electrochemical intercalation technology to successfully embed metal cations (K+ and Na+) into the interlayer structure of Ti3C2 MXene bulk, expanding the interlayer spacing from ∼10.50 to ∼13.10 Å by K+ intercalation, which can broaden electron/ion transport channels and enhance supercapacitor performance. Compared to the pristine Ti3C2 MXene bulk, the specific capacitance value increased by a factor of 2.8. Moreover, the intercalated MXene also exhibits excellent rate capability, with an increase from 47.32 to 70.20%. This work opens up a new path for the modification of Ti3C2 MXene bulk.

Rapid and eco-friendly ultrasonic exfoliation of transition metal dichalcogenides supported on sonogel-nanocarbon black: A non-precious electrocatalyst for hydrogen evolution reaction

Recently, there has been growing interest in replacing expensive platinum-based catalysts with cost-effective non-precious metal alternatives for water electrolysis aimed at hydrogen production. This study introduces an innovative, green, and cost-effective strategy for the development of non-precious electrocatalysts by leveraging sodium alginate-mediated ultrasonic exfoliation to produce transition metal dichalcogenide (TMD) nanosheets. These nanosheets are supported on Sonogel-Carbon electrodes (SGC), providing a novel conductive base for HER catalysis. Using a diverse array of TMD materials, including MoS2, MoSe2, WS2, and WSe2, we assess their catalytic activity towards HER. The study demonstrates significantly enhanced HER performance through bulk modification of the electrodes with nanocarbon black (SGC-CB). This enhancement is primarily due to the synergistic effects of improved electron transfer and increased active site availability, facilitated by the unique structural properties of the exfoliated TMD nanosheets and the conductive Sonogel-Carbon substrate. Notably, the optimized MoSe2NS-SGC-CB configuration achieves an exceptional overpotential of 240 mV at a current density of 10 mA/cm2, surpassing conventional bulk catalysts and highlighting the potential of sodium alginate as a viable dispersing agent for the large-scale production of TMD nanosheets. The operational stability and cost-effectiveness of this electrocatalyst, combined with its environmental friendliness, mark a significant step forward in the pursuit of sustainable hydrogen fuel production technologies.

Simultaneous bulk and surface modifications of g-C3N4 via supercritical CO2-assisted post-treatment towards enhanced photocatalytic activity

A high-temperature supercritical CO2 (ScCO2)-assisted post-treatment strategy is developed to simultaneously modify the bulk and surface structures of graphitic carbon nitride (g-C3N4) using ScCO2 as penetrant and a small amount of methanol/acetonitrile mixture as modifiers. Specifically, the product of modified g-C3N4 is obtained through the post-treatment of pristine g-C3N4 in a homogeneous ScCO2/methanol/acetonitrile system, continuously heating to reach a target temperature (330 °C, 15.2 MPa) without a residence time. With the assistance of ScCO2, organic molecules penetrate the interlayers of g-C3N4 and subsequently modify the in-plane structure of g-C3N4. Methanol induces the partial transformation of g-C3N4 into a carbon nitride with a poly(heptazine imide)-like structure and with abundant methyl and hydroxyl groups. Simultaneously, acetonitrile polymerizes into 2,4,6-trimethyl-1,3,5-triazine, which is then covalently grafted onto the surface of modified g-C3N4. Remarkably, the entire post-treatment process is completed within 5 min, achieving a final product yield of 92.3 %. The modified g-C3N4 photocatalyst achieves an H2-evolution rate of 2126.1 μmol·h−1·g−1 and a CO2-to-CO conversion rate of 874.1 µmol·h−1·g−1. This work provides a green, efficient, high-yield, and scalable strategy for preparing layered and porous non-metallic photocatalysts using supercritical fluids technology.

Chiral Bulk Solitons in Photonic Graphene with Decorated Boundaries

AbstractA chiral bulk soliton in a nonlinear photonic lattice with decorated boundaries, presenting a novel approach to manipulate photonic transport without extensive bulk modifications is proposed. Unlike traditional methods that rely on topological edge and corner modes, this strategy leverages the robust chiral propagation of bulk modes. By introducing nonlinearity into the system, a stable bulk soliton, akin to the topological valley Hall effects is found. The chiral bulk soliton exhibits remarkable stability; the energy does not decay even after a long‐distance propagation; and the corresponding Fourier spectrum confirms the absence of inter‐valley scattering indicating a valley‐locking property. The findings not only contribute to the fundamental understanding of nonlinear photonic systems but also hold significant practical implications for the design and optimization of photonic devices.

Elucidating the origin of laser induced nonlinearities in propagation inside transparent medias: A comparative numerical study of silicon and fused silica

Abstract The creation of localized bulk modification using femtosecond pulses inside semiconductors like silicon (Si) is quite challenging whereas it is not difficult to achieve it for dielectric material like fused silica (FS). So, this report addresses the fundamental origin of this issue. By taking simple numerical approach, it has been found that in FS we can deliver stronger fluence due to self-focusing on higher power level as compared to Si. The origin for the above lies on the spatial-temporal pulse-splitting behavior which is dominant in case of FS at the focus, whereas for Si it is only effective after focus. We have also considered the influence of plasma and Kerr terms to elucidate the reason behind such nonlinearities. For FS case, omission of Kerr term dominates whereas for Si the influence of each term does not significantly create self-focusing like FS under a similar focusing condition. This study could make an important guideline for researchers to understand the complexity of laser-matter interaction in transparent materials specifically being studied by many laser processing industries.

PVA-based formulations as a design-technology platform for orally disintegrating film matrices

In the majority of pharmaceutical applications, polymers are employed extensively in a diverse range of pharmaceutical products, serving as indispensable components of contemporary solid oral dosage forms. A comprehensive understanding of the properties of polymers and selection the appropriate methods of characterization is essential for the design and development of novel drug delivery systems and manufacturing processes. Orally disintegrating film (ODF) formulations are considered to be a potential substitute to traditional oral dosage forms and an alternative method of drug administration for children and uncooperative adult patients, including those with swallowing difficulties. A multitude of pharmaceutical formulations with varying mechanical and biopharmaceutical properties have emerged from the modification of the original polymeric bulk. Here we propose different formulation approaches, i.e. solvent casting (SC), 3D printing (3DP), electrospinning (ES), and lyophilization (LP) that enabled us to adjust the disintegration time and the release profile of poorly water soluble haloperidol (HAL, BCS class II) from PVA (polyvinyl alcohol) based polymer films while maintaining similar hydrogel composition. In this study, the solubility of haloperidol in aqueous solution was improved by the addition of lactic acid. The prepared films were evaluated for their morphology (SEM, micro-CT), physicochemical and biopharmaceutical properties. TMDSC, TGA and PXRD were employed for extensive thermal and structural analysis of fabricated materials and their stability. These results allowed us to establish correlations between preparation technology, structural characteristics and properties of PVA films and to adapt the suitable manufacturing technique of the ODFs to achieve appropriate HAL dissolution behaviour.

A green bulk modification for imparting a green VIPS membrane with antifouling properties

BackgroundMembrane preparation and membrane modification processes have long involved the use of toxic solvents. The present work proposes to only use envrionmentally-friendly solvents for both the fabrication and the surface modification of hydrophobic microfiltration membranes. In addition, coating processes for membrane modification are essentially surface modification processes. However, spray-coating may be a suitable method for both surface and bulk modification. MethodsAfter dissolving poly(vinylidene fluoride) in dimethylsulfoxide, membranes were formed by the vapor-induced phase separation process, and then modified using an aqeous solution of an amphiphilic copolymer containing poly(ethylene glycol) methyl ether methacrylate units. Then, a variety of physicochemical techniques were employed to characterize the membrane structure and prove the effectiveness of the surface/bulk modification. Antifouling tests in static and dynamic conditions were conducted. Significant findingsIt is possible to reduce the water contact angle of the top surface of the membrane from 135° to 0° and that of the bottom surface from 126° to 0° within <10 s, indicating successful hydrophilization of the membrane on the one hand, and top-to-bottom modification, despite solely exposing the top surface to the spray, on the other hand. This conclusion was confirmed by deidcated surface chemistry analyses. Besides, the membranes maintained their original highly porous and symmetric structure with light effects on surface porosity and pore size following the spray-coating process. The drasting improvement of hydrophilicity resulted in effective mitigation of fibrinogen adsorption (reduced by 85 %) and Escherichia coli adhesion (reduced by 86 %). Fouling during cyclic filtration involving a bacterial suspension was also effectively reduced with a flux recovery ratio of 53 % (against 37 % for a commercial hydrophilic membrane) and an irreversible flux decline ratio of 47 % (against 63 % for a commercial hydrophilic membrane) in the conditions of the test.

Gradient doping–induced triphasic intergrowth hexacyanoferrate cathode for high-performance sodium-ion batteries

As a high-capacity, high-voltage, and low-cost cathode material for sodium-ion batteries (SIBs), Na/Mn-based hexacyanoferrates (NaxMn[Fe(CN)6]1−y·□y·nH2O) typically exhibit poor structural reversibility and interfacial stability during cycling. In this study, we report the in-situ construction of a triphasic intergrowth Na/Mn/Zn-based hexacyanoferrate (mcr-Zn0.2Mn0.8) with concentration-gradient Zn distribution by an anion-controlled fractional precipitation route. Density functional theory calculations verify that the unique heterostructure arises from the different binding energies between cations and anions. A small amount of Zn2+ doping in the inner cubic/monoclinic phases enhances their structural reversibility during cycling by impeding lattice deformation induced by the Jahn–Teller effect of Mn3+. Meanwhile, the rhombohedral Zn-based hexacyanoferrate epitaxially grown on the surface diminishes the particle size of mcr-Zn0.2Mn0.8 resulting in short Na+ diffusion distance, and provides interface protection that suppresses detrimental electrolyte decomposition. Consequently, mcr-Zn0.2Mn0.8 exhibits a high discharge capacity of 121.1 mAh/g at 15 mA g−1, improved cycling stability at 750 mA g−1 with a capacity retention of 65.0 % after 2000 cycles, and enhanced rate capability with a discharge capacity of 71.4 mAh/g at 6000 mA g−1. The successful implementation of simultaneous surface and bulk modifications through a one-step reaction opens new possibilities for developing high-performance hexacyanoferrate cathode materials for SIBs.

Investigation of physical, thermal and morphological properties of CuCl2 modified polyurethane sponges

There are many types of polyurethane sponge (PUS), depending on properties such as hardness, flexibility and surface texture. The fact that it can be produced in any shape and size has given it very wide range of applications. Surface modification is one of the most commonly used methods to improve the performance of PUS. Here, inspired by metal coordination polymers, a simpler and faster method for surface modification of PUS with metal ions compared to bulk modification was proposed. In the case of copper, which is often used for PUS modification, the change in the basic properties sought in different applications as a function of the concentration of the modifier was investigated. Samples prepared by immersing sponges in solutions of copper chloride salt were subjected to physical, thermal and morphological analyses. Due to the modification, the coordination bonds between CuCl2 and polyurethane were revealed by XPS and FTIR. SEM and EDS studies of the PUS revealed both closed and open cells. DSC and TGA analysis showed that the obtained product had better thermal stability than the unmodified product. When the PUS was modified with 0.5 Cu, the water contact angle increased from 101.32° to 135.01° and hydrophobic properties were imparted to all pore surfaces, and the desired properties such as porosity, density could be adjusted. Furthermore, it is envisaged that the surface, mechanical and thermal properties will make it suitable for use in a range of practical applications such as medical and environmental.

Multiphoton-initiated laser writing of semiconductors using nanosecond mid-infrared pulses

The advent of more powerful mid-infrared nanosecond laser sources allows using them as attractive tools in material laser processing. For semiconductor bulk processing, laser intensities must remain modest to avoid detrimental nonlinear propagation and pre-focal plasma screening effects. Accordingly, nanosecond pulses are usually appropriate to locally initiate energy deposition by multiphoton absorption and subsequent modification, hardly achievable with ultrashort pulses. Employing a 2.8-μm 2.5-ns laser source, we explore the possibility to modify silicon and other semiconductors. With interactions initiated by three-photon absorption, we modify and determine the surface and bulk modification thresholds of Si, GaAs, and InP. For Si, compared to previous studies at telecom wavelengths, we report on a reduction of the energy threshold for volume modification with processing depth, and repeatable rear-surface modifications. Compared to Si, we find for GaAs and InP important fluctuations in the modification responses, which we attribute to an absorption mechanism initially triggered by a greater presence of defects. We also study germanium, as this narrower bandgap semiconductor very interesting for mid-infrared electro-optical applications is transparent at the newly introduced wavelength. Despite the ability to modify the surface, the bulk of Ge remains inaccessible in this two-photon regime, mainly attributed to beam aberrations and nonlinearities. Nonetheless, we demonstrate the ability to process Si chips integrating Ge layers. All these results showcase the potential of mid-infrared wavelengths to offer new degrees of flexibility for 3D laser processing technologies turned to silicon photonics and microelectronics packaging.

Direct Defluorination and Amination of Polytetrafluoroethylene and Other Fluoropolymers by Lithium Alkylamides.

Polytetrafluoroethylene (PTFE) and, by extension, fluoropolymers are ubiquitous in science, life, and the environment as perfluoroalkyl pollutants (PFAS). In all cases, it is difficult to transform these materials due to their chemical inertness. Herein, we report a direct amination process of PTFE and some fluoropolymers such as polyvinylidene fluoride (PVDF) and Nafion by lithium alkylamide salts. Synthesizing these reactants extemporaneously between lithium metal and an aliphatic primary di- or triamine that also serves as a solvent leads to the rapid nucleophilic substitution of fluoride by an alkylamide moiety when in contact with the fluoropolymer. Moreover, lithium alkylamides dissolved in suitable solvents other than amines can react with fluoropolymers. This highly efficient one-pot process opens the way for further surface or bulk modification if needed, providing an easy, inexpensive, and fast experiment protocol on large scales.

Research on the performance of foamed concrete based on superhydrophobic bulk modification

Foamed concrete is a kind of lightweight insulation material formed by the uniform mixture of foam and cement slurry. The superhydrophobic bulk modification of foamed concrete can reduce its high water absorption and prolong its service life. In this paper, the compatibility of three hydrophobic agents named polydimethylsiloxane (PDMS), isoctyltriethoxysilane (ICTS) and SBT®-TIA with foams was studied, and the reasons of incompatibility were revealed. Then, the superhydrophobic bulk foamed concrete system was constructed by physical foaming method, adding polydimethylsiloxane (PDMS), calcium stearate (CS), nano-silica (NS) and covering the surface of the specimen with 200-mesh wire mesh. The results show that the maximum contact angles of the meshed surface and the internal polished surface of superhydrophobic foamed concrete were 162.7° and 153.5°, respectively. At the same time, the water absorption rate of the modified specimen was significantly reduced, and the reduction rate was up to 90 %. In addition, the deterioration degree of thermal insulation performance after soaking and the dry shrinkage rate were significantly reduced compared with ordinary foamed concrete. Scanning electron microscopy (SEM) revealed that increasing the multi-scale roughness could improve the hydrophobic properties of foamed concrete. Fourier infrared spectroscopy (FT-IR) also confirmed that low surface energy groups such as -CH2 and -CH3 in PDMS bonded to the cement hydration products, indicating the successful preparation of superhydrophobic bulk foamed concrete.

A superhydrophobic mortar with ultra-robustness for self-cleaning, anti-icing, and anti-corrosion

Superhydrophobic cement-based materials are promising candidates to alleviate the performance deterioration of concrete constructions caused by water penetration. However, the weak mechanical performance of superhydrophobic surfaces, and severe reduction in compressive strength due to bulk modification, present significant challenges for the application of superhydrophobic cement-based materials. In this work, a superhydrophobic mortar (S-mortar) was prepared using a facile and economical method by surface micro-nano roughness construction and matrix silane modification, and nano-silica was introduced to compensate for the strength loss. The obtained S-mortar exhibits superb surface mechanical durability and chemical stability, no significant decrease in superhydrophobic property after sandpaper rubbing, knife scratches, and exposure to extreme temperatures, while even new surfaces exposed by cutting and powders obtained by grinding possess excellent water repellency. Furthermore, the superhydrophobicity endows the S-mortar with self-cleaning, anti-fouling, anti-icing, anti-freezing, and anti-corrosion properties. This approach creates a balance between superhydrophobic property and mechanical performance, broadening application prospects of superhydrophobic cement-based materials.

Nanoprecipitation to produce hydrophobic cellulose nanospheres for water-in-oil Pickering emulsions

In recent years, there has been growing interest in replacing petroleum-based water-in-oil (W/O) emulsifiers with sustainable and less toxic natural materials. Pickering emulsifiers are considered well-suited candidates due to their high interfacial activity and the ability to form emulsions with long-term stability. However, only sporadic examples of natural materials have been considered as inverse Pickering emulsifiers. This study describes the synthesis of a series of hydrophobic cellulose nanospheres by bulk modification with acyl groups of different chain lengths followed by nanoprecipitation, and their application as inverse emulsifiers. Modification with acyl groups of longer chain length (C16, C18) afforded lower degrees of substitution, but resulted in greater thermal stability than groups with shorter acyl chains (C12, C14). Formation of nanospheres with low aspect ratios and narrow size distributions required low initial cellulose concentrations (< 1% w/v), high volumetric ratios of antisolvent to solvent (> 10:1), and slow addition rates (< 20 mL/h). The modified cellulose nanospheres were able to reduce the interfacial tension between water and hexane from 45.8 mN/m to 31.1 mN/m, with an effect that increased with the number of carbons in the added acyl chains. The stearate-modified nanospheres exhibited superhydrophobic behavior, showing a contact angle of 156° ± 4° with water, and demonstrated emulsification performance comparable to the commonly used molecular surfactant sorbitan stearate. Our findings suggest that hydrophobically modified cellulose nanospheres have the potential to be a bio-derived alternative to traditional molecular W/O emulsifiers.Graphical

Hybrid Surface Modification and Bulk Doping Enable Spent LiCoO2 Cathodes for High-Voltage Operation.

The emerging market demand for high-energy-density of energy storage devices is pushing the disposal of end-of-life LiCoO2 (LCO) to shift toward sustainable upgrading into structurally stable high-voltage cathode materials. Herein, an integrated bulk and surface commodification strategy is proposed to render spent LCO (S-LCO) to operate at high voltages, involving bulk Mn doping, near surface P gradient doping, and Li3PO4/CoP (LPO/CP) coating on the LCO surface to yield upcycled LCO (defined as MP-LCO@LPO/CP). Benefiting from hybrid surface coating with Li+-conductive Li3PO4 (LPO) and electron conductive CoP (CP) coupled with Mn and P co-doping, the optimized MP-LCO@LPO/CP cathode exhibits enhanced high-voltage performance, delivering an initial discharge capacity of 218.8 mAh g-1 at 0.2 C with excellent capacity retention of 80.9% (0.5 C) after 200 cycles at a cut-off voltage of 4.6V, along with 96.3% of capacity retention over 100 cycles at 4.5V. These findings may afford meaningful construction for the upcycling of commercial S-LCO into next-generation upmarket cathode materials through the elaborate surface and bulk modification design.

Novel MXene/PVDF nanocomposite ultrafiltration membranes for optimized Eriochrome black T (azo dye) removal

In the context of recycling and reusing textile wastewater, the quest for a membrane possessing superior efficiency has garnered considerable attention. This research endeavors to advance this objective by introducing a novel asymmetric ultrafiltration membrane constructed from PVDF (Polyvinylidene Fluoride) modified with MXene through bulk modification, thereby augmenting its resistance to fouling for textile wastewater treatment applications. The investigation employed a comprehensive array of characterization techniques. The proposed interaction mechanism between the contents of PVDF/MXene and the interaction mechanism of composite membrane with water molecules were also presented. Comparative analysis with pure membranes revealed that the incorporation of MXene resulted in enhanced hydrophilicity and porosity, concurrently reducing its surface roughness when compared to a pristine membrane. The lowest water contact angle about 38.5 (⁰) was observed in the mixed matrix membrane containing 0.5 wt% MXene. The developed membranes exhibited a maximum pure water flux of 538 LMH and a flux of 467.8 LMH for EBT dye solution. Furthermore, optimization of the nanocomposite membrane composition led to nearly complete rejection of Eriochrome black T (EBT). A continuous improvement in the flux recovery ratio (FRR%) culminating in a peak value of 85.6% for the MMMs prepared from 0.5 wt% MXene.

Highly Conductive Doped Fluoride Solid Electrolytes with Solidified Ionic Liquid to Enable Reversible FeF3 Conversion Solid State Batteries

AbstractSolid‐state lithium metal batteries based on fluorinated solid electrolytes have attracted attention due to their safety and stability advantages. However, the fluoride solid electrolytes face the problem of relatively low Li‐ion conductivity due to the lacking of suitable structural prototypes and their corresponding modulation modes. In this work, a chlorine‐doped fluoride solid electrolyte Li3AlF5.87Cl0.13 is developed with high ionic conductivity by thermal fluorination and weak chlorination of mixed ionic liquids. The Cl anion is doped into the cryolite‐like open framework structure, and the electrolyte particle boundaries are decorated by solidified thin‐layer (≈2 nm) ionic liquid. Both the bulk and interface modifications enable the improvement of Li‐ion conductivity to 2 × 10−4 S cm−1 at 30 °C, which is the highest level among fluoride solid electrolytes. The Li3AlF5.87Cl0.13 with residual solidified ionic liquid shows the excellent stability of interface contact with Li metal, and the corresponding Li symmetric cell exhibits a small overvoltage (≈100 mV) with outstanding cycle life (at least 500 h). For the first time, a conversion‐type solid‐state Li/FeF3 battery is developed based on this fluoride electrolyte, delivering a reversible capacity as high as 430 mAh g−1. The existence of natural F‐rich interface promotes the conversion reaction reversibility of FeF3 cathode.

Recent Progress on the Surface and Bulk Modification of Carbon Nitrides for Photocatalytic Carbon Dioxide Reduction

Photocatalytic CO2 reduction has been considered as a green and sustainable approach to solve energy and environmental problems. However, the CO2 reduction efficiency of various types of semiconductor photocatalysts studied at this stage is far from realizing practical applications. The challenge of photocatalytic CO2 reduction is to design photocatalysts with excellent catalytic performance. This article summarizes the carbon nitride materials for efficient CO2 reduction and obtaining high value‐added products. The physicochemical properties of carbon nitride materials are discussed in terms of the photocatalytic mechanisms (bandgap tuning, high specific surface area, shorter electron–hole transmission paths, increasing the number of active sites, etc.). The present review provides the latest research progress of carbon nitride modification strategies. The prospects and challenges for the application of carbon nitride materials for CO2 reduction are presented. This review article will provide useful guidance for further research on carbon nitride materials for efficient photocatalytic CO2 reduction.