Thermal Condensation Research Articles

Facile Synthesis And Characterization Of gCN, gCN-Zn And gCN-Fe Binary Nanocomposite And Its Application As Photocatalyst For Methylene Blue Degradation

Thermal condensation method to obtain for pure graphitic carbon nitride (gCN) and two binary nanocomposites, gCN-Zn - gCN-Fe have been used in the present study. The structural, morphological, thermal and optical characterizations of the syhtesized samples were characterized with X-ray diffraction, scanning electron microscopy, thermogravimetric analysis (TGA) and UV-Vis spectroscopy. The intensity of characteristic gCN peak at (002) crystalline plane decrease with formation of binary nanocomposites was observed. The EDX spectra supports presents of Zn and Fe element in binary nanocomposites. The bandgap of pristine gCN is calculated as 2.75 eV and it decreases to 2.58 eV and 2.50 eV for Zn and Fe addition. The degradation capacity of pristine gCN and synthesized binary nanocomposites showed an enhanced photodegradation performance for binary composite relative to pristine gCN was observed. The maximum degradation performance was observed at gCN-Zn binary composite. The obtained composites with this simple synthesis method and cost effective raw materials used for the photodegradation of methylene blue dye detail.

Enhanced electron density of the π-conjugated structure and in-plane charge transport to boost photocatalytic H2 evolution of g-C3N4

Graphite carbon nitride (g-C3N4) has become an emerging metal-free photocatalyst and attracted the attention of researchers. However, pure g-C3N4 (PCN) prepared by traditional thermal condensation polymerization has a low polymerization of heptazine ring chains and a large number of charge recombination centers, which hinder in-plane charge transport, leading to undesirable photocatalytic performance. Herein, PCN fabrication by thermal treatment with ammonium oxalate monohydrate was performed to produce highly dispersed porous g-C3N4 nanosheets, and the integrity of their in-plane heptazine ring chains was successfully improved without introducing heteroatoms. Electron paramagnetic resonance and 13C nuclear magnetic resonance analyses revealed significantly increased electron density and delocalization of the π-conjugated structure. The obtained samples exhibited acceptable stability and photocatalytic activity, and the hydrogen reduction rates without and with the Pt co-catalyst were 11.2 and 5.3 times that of PCN.

In Situ Prepared Three-Dimensional Covalent and Hydrogen Bond Synergistic Binder to Boost the Performance of SiOx Anodes for Lithium-Ion Batteries

Polymer binders play an important role in enhancing the electrochemical performance of silicon-based anodes to alleviate the volume expansion for lithium-ion batteries. It is difficult for common one-dimensional (1D) linear binders to limit the volume expansion of a silicon-based electrode when combined with silicon-based particles with scant binding points. Therefore, it is necessary to design a three-dimensional (3D) network structure, which has multiple binding points with the silicon particles to dissipate the mechanical stress in the continuous charge and discharge circulation. Here, a covalent and hydrogen bond synergist 3D network green binder (poly(acrylic acid) (PAA)-dextrin 9 (Dex9)) was prepared by the simple in situ thermal condensation of a one-dimensional liner binder PAA and Dex in the electrode fabrication process. The optimized SiOx@PAA-Dex9 electrode exhibits an initial Coulombic efficiency (ICE) of 82.4% at a current density of 0.2 A g-1. At a high current density of 1 A g-1, it retains a capacity of 607 mAh g-1 after 300 cycles, which is approximately twice as high as that of the SiOx@PAA electrode. Furthermore, the results of in situ electrochemical dilatometry (ECD) and characterization of electrode structures demonstrate that the PAA-Dex9 binder can effectively buffer the huge volume change and maintain the integrity of the SiOx electrodes. The research overcomes the low electrochemical stability difficulty of the 3D binder and sheds light on developing the simple fabrication procedure of an electrode.

Triazine-free polyimide for photocatalytic hydrogen production

Polyimide (PI) has received considerable attention as a promising donor-acceptor polymer for photocatalytic hydrogen production, yet the previous studies entirely focused on the exploration of triazine-based PI. Herein, we report for the first time triazine-free PI for photocatalytic hydrogen evolution. The triazine-free PI was synthesized by thermal condensation of urea and pyromellitic dianhydride. The resultant PI photocatalyst yielded a stable hydrogen evolution activity and an appreciable photocurrent response. This work manifests that triazine is not an indispensable unit for the photocatalytic hydrogen evolution activity of PI, which expands the chemical library of PI photocatalysts and opens up new opportunities for designing efficient polymeric photocatalysts.

Polypeptide Chain Growth Mechanisms and Secondary Structure Formation in Glycine Gas-Phase Deposition on Silica Surfaces.

Peptide formation by amino acids condensation represents a crucial reaction in the quest of the origins of life as well as in synthetic chemistry. However, it is still poorly understood in terms of efficiency and reaction mechanism. In the present work, peptide formation has been investigated through thermal condensation of gas-phase glycine in fluctuating silica environments as a model of prebiotic environments. In-situ IR spectroscopy measurements under a controlled atmosphere reveal that a humidity fluctuating system subjected to both temperature and water activity variations results in the formation of more abundant peptides compared to a dehydrated system subjected only to temperature fluctuations cycles. A model is proposed in which hydration steps result in the hydrolysis and redistribution of the oligomers formed during previous deposition in dry conditions. This results in the formation of self-assembled aggregates with well-defined secondary structures (especially β-sheets). Upon further monomers feeding, structural elements are conserved in newly growing chains, with indications of templated polymerization. The structural dynamics of peptides were also evaluated. Rigid self-assembled structures with a high resistance to further wetting/drying cycles and inaccessibility to isotopic exchange were present in the humidity fluctuating system compared to more flexible structures in the dehydrated system. The resistance and growth of self-assembled structures were also investigated for an extended duration of Gly deposition using isotope labeling.

Application potential analysis of different control strategies for radiant floor cooling systems in office buildings in different climate zones of China

The application potential of radiant floor cooling systems is affected by climatic conditions. The meteorological parameters of 22 cities in five climatic zones in China (severe cold (SC), cold, hot summer and cold winter (HSCW), hot summer and warm winter (HSWW), and temperate) are analyzed to evaluate the applicability of four conventional control strategies of radiant floor cooling system in office buildings. The control strategies are modeled in the Transient System Simulation Program (TRNSYS), and the indoor thermal comfort, condensation risk, energy consumption, and carbon emissions are analyzed. Multi criteria decision-making is used to evaluate the radiant floor system. The results show that the control strategy with direct ground cooling produces the highest energy savings in the five climate zones. The energy savings are 25–66 % higher than those of the three control strategies using a heat pump as a cold source. Under the same indoor environment conditions, the three-step control strategy provides the optimum indoor temperature and humidity control. The number of hours when the three-step control strategy exceeds the thermal comfort zone is 5 % in 22 cities, and the number of hours with condensation risk is only 3%. The variable water supply temperature control and precooling control have better performance than the other strategies in the SC, cold, and temperate zones. In addition, the control strategies are ranked based on their application potential in 22 cities. The application potential of the radiant floor cooling system with a direct ground cooling source is the highest in the five climate zones in the two scenarios with equal weights of the four criteria and is preferable due to less carbon emissions. When the condensation risk is considered, the radiant floor cooling system with a direct ground cooling source exhibits better performance in the SC and cold zones. The variable water supply temperature control is the optimum strategy in the HSCW, HSWW, and temperate zones. The precooling control strategy ranks the highest in Changchun and Guiyang, and the three-step control strategy performs the best in Shanghai.

Кинетические особенности термолиза газойлей каталитического крекинга

The high-temperature macrokinetics of the process of thermolysis of low-sulphur catalytic cracking gas oil with the formation of needle coke was studied. The experiments were carried out on a laboratory setup with a quartz microreactor at temperatures of 450-500 °C and a process duration of up to 300 min. It was established that the process is two-stage and its kinetics obeysthe Avrami-Erofeev equation, the rate constant of the process at both stages has a diffusion character. The second stage includes thermal condensation of polycyclic hydrocarbons with the formation of mesophase and needle coke. The results of the study are confirmed by optical microscopy in polarized light, data of electron paramagnetic resonance and electron spectroscopy.

Multiscale modification of carbon nitride-based homojunction for enhanced photocatalytic atrazine decomposition.

Herein, PDI-g-C3N4/g-C3N4 homojunction has been fabricated via the multiscale modification strategy to enhance photocatalytic atrazine degradation. The morphological scale modification was realized by multistep thermal condensation, where the released gas could act as templates to form the porous structure. The molecular scale modification was achieved by the pyromellitic diimide (PDI) decoration, which could distort the planar nanosheet to induce a porous structure and provide more chromophores for better light absorption. The electronic scale modification was realized by the built-in electric field between the PDI-g-C3N4/g-C3N4 homojunction interfaces, which suppressed the recombination of photocarriers. The PDI-g-C3N4/g-C3N4 strengthened photocatalytic atrazine degradation was well-adapted to different environmental influence interference. The optimum atrazine degradation rate within one hour reached 90% in a strong acidic condition (pH=3.09). It was found that the highly pH-dependent ATZ removal is related to the H2O2 generation during photocatalysis. Within one hour, the PDI-g-C3N4/g-C3N4 could generate 147.38μM H2O2. In addition, 1O2, ·O2-, h+, and ·OH were found to have contributed to the ATZ decomposition. During photocatalysis, 14 intermediates and three pathways for atrazine degradation have been found. Hopefully, this study could pave a way for the development of the multiscale modification for the photocatalyst.

Facile synthesis of Ru nanoclusters embedded in carbonaceous shells for hydrogen evolution reaction in alkaline and acidic media

Exploring effective electrocatalyst with low-cost for hydrogen evolution reaction (HER) is highly desirable for commercial hydrogen production. Herein, a heterogeneous nanostructured catalyst is synthesized by implanting Ru nanoclusters into N and S co-doped carbonaceous shell using a simple thermal condensation of glucose and thiourea with ruthenium chloride precursors followed by carbonization. Due to the unique structural design and synergistic effect of Ru nanoclusters embedded in N, S co-doped carbonaceous shell (NSC), the compositionally tuned catalyst (Ru/NSC-200) tends to show HER activity with overpotentials of 50 and 110 mV at 10 mA cm−2 current density in 1 M KOH and 1 M KHCO3 solutions, respectively. The catalyst exhibits mass activity of 10- and 1.2-times greater than those of commercial Pt/C (20 wt%) in 1 M KOH and 0.5 M H2SO4 solutions, which reveals the techno-economic trait of the catalyst. Density functional theory (DFT) calculations demonstrate that the NSC induces a strong interaction with Ru, facilitating fast electron transfer during the catalysis. This work provides a simple and straightforward approach to develop effective catalyst in the realm of hydrogen evolution reaction.

Ti–N coordination bonds boost Z-scheme interfacial charge transfer in TiO2/C-deficient g-C3N4 heterojunctions for enhanced photocatalytic phenolic pollutant degradation

Rational designing of chemical bond-bridged TiO2-based Z-scheme heterojunctions and deep understanding mechanism of significantly enhanced visible-light photocatalytic performance of the heterojunctions is a hotspot in photocatalysis. Herein, a defect-engineering strategy is developed to fabricate Ti–N coordination bond-bridged TiO2/C-deficient g-C3N4 heterojunctions (TiO2/VC-CN), and the preparation process includes formaldehyde-assisted preorganization of molten urea in the presence of titanium isopropoxide followed by thermal condensation. The detailed characterization results evidence the formation of a unique atomic-level heterojunction contact interface via Ti–N coordination bonds in TiO2/VC-CN, in which N atoms around the C vacancies of g-C3N4 donate electrons to unoccupied Ti 3d orbitals of TiO2. At the optimal TiO2 doping level, the TiO2/VC-CN heterojunctions exhibit remarkably high visible-light photocatalytic oxidation performance in the degradation of recalcitrant phenolic pollutants, methylparaben and acetaminophen, which outperforms commercially available P25 TiO2, as-prepared anatase TiO2 and bulk g-C3N4. The experimental results combined with theoretic calculations reveal that the outstanding interfacial Ti–N coordination bonding remarkably boosts the direct Z-scheme charge carrier transfer in the TiO2/VC-CN heterojunctions, which results in the generation of plentiful reactive oxidation species including O2−, OH and 1O2 for efficient removal of the target pollutants.

1H and 13C NMR Study of Oligosuccinimide Prepared by Thermal Condensation and Evaluation of Its Scale Inhibition

<p>The presence of scale is a serious problem in the petroleum industry, and some efforts should be made to control scale formation. Oligosuccinimide (OSI) is an oligomer with several repeating units of succinimide. The structure of the OSI main chain and end groups has never been comprehensively analyzed. Meanwhile, OSI is potentially a scale inhibitor due to chelating properties, high polarity, and high solubility. This study investigates the molecular structure of oligosuccinimide, focusing on the main chain and end groups. Synthesis was carried out by thermal condensation between maleic anhydride and ammonium carbonate using a <sup>1</sup>H and <sup>13</sup>C NMR spectroscope equipped with Distortionless Enhancement by Polarization Transfer 135, Heteronuclear Multiple Quantum Coherence, and Single Quantum Coherence. The NMR analysis results detected the presence of the main chain and several synthesized OSI end groups, such as the amino, succinimide, and maleimide end groups. However, the dicarboxylic acid end group and other irregular structures, as in polysuccinimide (various synthesis methods), were not identified. It confirmed that our thermal condensation method produced OSI with less irregular structures than previous methods. Evaluation of OSI as CaCO<sub>3</sub> and CaSO<sub>4</sub> scales inhibitor showed reasonably good performance in very small concentrations. The inhibition efficiency was 73.20% for the CaCO<sub>3</sub> scale with 10 mg.L<sup>-1</sup> and 55.29% for the CaSO<sub>4</sub> scale with 10 mg.L<sup>-1</sup> inhibitor concentration. Analysis of thermal stability informed OSI has good thermal stability because it started to be degraded at 353.38 °C.</p>

Supramolecular preorganization synthesis of nitrogen-doped carbon nanotubes functionalized by Brønsted acidic ionic liquid for microwave-assisted production of promising furanic derivatives

Brønsted acidic ionic liquids functionalized nitrogen-doped carbon nanotubes catalysts, [C4SO3HN][OTf]-NCNTs (OTf = SO3CF3), are synthesized by an additive-free supramolecular preorganization-thermal condensation route followed by chemical modification. By controlling the molar composition of carbon–nitrogen based monomers, sequence of the monomers and thermal condensation temperature, the tubular morphology and porosity properties of the catalysts are well-adjusted. The [C4SO3HN][OTf]-NCNTs are successfully applied in the reactions of great relevance to the development of sustainable bio-economy, namely, microwave-assisted production of 5-hydromethylfurfural (HMF) and furfural (FFR) from the dehydration of fructose and xylose, and the important reaction parameters including microwave irradiation temperature and time as well as solvent are considered. Co-operation of strong Brønsted acidity, unique tubular nanostructures and microwave heating approach finally endows [C4SO3HN][OTf]-NCNTs the enhanced dehydration reactivity and selectivity, in which the [C4SO3HN][OTf]-NCNTs800-2 with perfect tubular nanostructures displays the highest HMF yield (82.6%, 15 min in THF media) and FFR yield (56.2%, 45 min in DMSO media). The [C4SO3HN][OTf]-NCNTs also exhibit good catalytic reusability, attributing to covalent bonding of the [C4SO3HN+][OTf−] units onto NCNTs frameworks; meanwhile, the formation of considerable amount of humins at the surface of the catalysts is effectively inhibited by using microwave heating mode.

Application of Thermal Response Measurements to Investigate Enhanced Water Adsorption Kinetics in Ball-Milled C2 N-Type Materials.

Sorption-based water capture is an attractive solution to provide potable water in arid regions. Heteroatom-decorated microporous carbons with hydrophilic character are promising candidates for water adsorption at low humidity, but the strong affinity between the polar carbon pore walls and water molecules can hinder the water transport within the narrow pore system. To reduce the limitations of mass transfer, C2 N-type carbon materials obtained from the thermal condensation of a molecular hexaazatriphenylene-hexacarbonitrile (HAT-CN) precursor were treated mechanochemically via ball milling. Scanning electron microscopy as well as static light scattering reveal that large pristine C2 N-type particles were split up to a smaller size after ball milling, thus increasing the pore accessibility which consequently leads to faster occupation of the water vapor adsorption sites. The major aim of this work is to demonstrate the applicability of thermal response measurements to track these enhanced kinetics of water adsorption. The adsorption rate constant of a C2 N material condensed at 700 °C remarkably increased from 0.026 s-1 to 0.036 s-1 upon ball milling, while maintaining remarkably high water vapor capacity. This work confirms the advantages of small particle sizes in ultramicroporous materials on their vapor adsorption kinetics. It is demonstrated that thermal response measurements are a valuable and time-saving method to investigate water adsorption kinetics, capacities, and cycling stability.

Synthesis of g-C3N4 from Various Precursors for Photocatalytic H2 Evolution under the Visible Light

Graphitic carbon nitride (g-C3N4) fabricated from different precursors exhibits unique microstructures and photocatalytic performance under visible light. Herein, we synthesized five different microstructures of g-C3N4 by the thermal poly condensation method using guanidine hydrochloride, melamine, urea, dicyandiamide and thiourea as the precursors. The results indicated that g-C3N4 prepared from urea precursor (UCN) has a nanostructure, porous layered structure, large specific surface area, and high separation efficiency of photo generated hole-electron pairs, which showed the best photocatalytic activity among all of the as-prepared samples. As for the lowest cost among the above five precursors, urea is an ideal candidate material for preparing g-C3N4 photocatalyst for a huge potential of wide industrial applications. In addition, Pt or Ni were used as the co-catalyst and loaded onto the g-C3N4 surface for photocatalytic hydrogen production. In comparison with noble metal Pt co-catalyst, Ni co-catalyst is inexpensive and has a significant effect o enhancing the photocatalytic activity under visible light. Therefore, Ni exhibits a considerable prospect to replace noble metal co-catalysts in the photocatalytic reactions.

Tuning the optical properties of high quantum-yield g-C[formula omitted]N[formula omitted] with the inclusion of ZnS via FRET for high electron–hole recombination

Luminescent polymeric graphitic composites have the potential to be efficient energy converters for sophisticated displays and light sources. Thermal condensation is used to synthesize g-C3N4-ZnS composites. The XRD, and FTIR analyses confirmed the synthesis of the pure host, filler, and composites. FESEM, and TEM images revealed that the ZnS nanosheets were evenly distributed over the g-C3N4 sheets. As a result of ZnS incorporation, the melting point of g-C3N4 has been raised to 748.5 °C, and the thermal stability of gZ has been increased by 27 %. The optimized gZ15 band gap is determined to be 2.98 eV with a crystallite size of 4.2 nm and a micro stain of 35.42 × 10−3. With a purity of 63.4 %, gZ15 demonstrated a significant rate of recombination in the blue region. gZ15 has a high PLQY of 98 % and a FRET efficiency of 92%. All of the improved properties demonstrated that polymeric g-C3N4-ZnS was the optimum materials for usage in the active or emissive layer of optoelectronic devices.

Durable and regenerative superhydrophobic surface using porous nanochannels

Despite substantial advancements in development of artificially engineered superhydrophobic surfaces, durability and regenerative aspect of such surfaces remain elusive. Harsh working condition, especially extreme exposure to water or humidity deteriorates plastron property of superhydrophobic surfaces rendering them inappropriate for prolonged under-water applications. We report a systematic approach for creating a durable superhydrophobic surface by first plasma-treating a fabricated porous nanochannel geometry on a silicon substrate followed by infusion-depletion of silicon oil and coating a layer of carbon derived from candle soot. The surface is capable of maintaining water contact angle (WCA) of nearly 160° and roll off angle (ROA) less than 5° after undergoing 20 different tests including mechanical (tap water jet up to 10.3ms-1, tape peeling test up to 12 cycles), chemical (saline and solvents immersion), thermal (high temperature exposure and condensation heat transfer), self-cleaning tests, organic compatibility (honey, soy sauce, chocolate syrup, all-purpose flour) and superoleophilic test, thus exhibiting potential real-world applications. The surface retains stable plastron with negligible change in WCA and ROA even after being under 10cm of water for 30 days, similar to respiration plastrons seen on some aquatic insects. Regenerative capability of the surface is demonstrated by restoring its superhydrophobicity from a forced degraded state.

One-pot preparation of poly(triazine imide) with intercalation of Cu ions: A heterogeneous catalyst for peroxymonosulfate activation to degradate organic pollutants under sunlight

• One-pot preparation of poly(triazine imide) with intercalation of Cu + ions. • The catalyst was efficient in the activation of peroxymonosulfate. • The catalyst demonstrated a wide pH application range and excellent stability. • Possible formation mechanism of the catalyst and degradation pathways of pollutants were studied. A novel poly(triazine imide) (PTI)with intercalation of Cu ion heterogeneous catalysts (Cu/PTI) was synthesized by one-pot thermal condensation of melamine and copper acetate as precursors, resulting in a material with stoichiometry of C 6 N 8.7 Cu. The microscopic morphology and structural characteristics of Cu/PTI were characterized by XRD, SEM, TEM, FT-IR, and XPS. The characterization results corroborated the highly condensed triazine-based structure, and copper mainly existed in the form of Cu + . The possible formation mechanism of composite materials was proposed. The prepared composite Cu/PTI catalyst was used to activate PMS to enhance the simulated pollutant RhB degradation under sunlight irradiation. The experimental results show that sunlight could improve the activation efficiency of Cu/PTI to PMS, Cu/PTI(1:4) had the best activation ability, and the degradation rate of RhB reached 96.2% in 60 min, nearly doubling that without sunlight. Critical impacting factors, initial solution pH was investigated in terms of the catalytic efficiency. The catalyst has a high ability to activate PMS to degrade pollutants in the range of pH = 3–10. In addition, quencher experiments demonstrated that O 2 · - , 1 O 2 , h V B + , and S O 4 · - are the main active species, and a detailed catalytic mechanism was proposed. Thus, the enhanced reactivity of the Cu/PTI catalyst was attributed to the existence of dual catalytic sites and the synergistic effect between Cu and PTI. This strategy provides a feasible way to treat wastewater using Cu/PTI with PMS under sunlight.

A Novel Nanocomposite Based on Triazine Based Covalent Organic Polymer Blended with Porous g-C3N4 for Photo Catalytic Dye Degradation of Rose Bengal and Fast Green.

Metal free visible light active photocatalysts of covalent organic polymers (COPs) and polymeric graphitic carbon nitride (g-C3N4) are interesting porous catalysts that have enormous potential for application in organic pollutant degradation. Imine condensation for COPs, and thermal condensation for g-C3N4 were used to produce the catalysts. FT-IR, Raman, NMR, UV-Vis Spectroscopy, X-ray diffraction, and scanning electron microscopy studies were used to investigate the structural, optical, and morphological features of the metal free catalysts. We have constructed COPs with a π-electron deficient (Lewis acidic) triazine core and π -electron rich (Lewis basic) naphthalene and anthraquinone rings coupled by -O and -N donors in this study. Furthermore, the prepared Bulk-g-C3N4 (B-GCN) was converted to porous g-C3N4 (P-GCN) using a chemical oxidation process, and the generated P-GCN was efficiently mixed with the COP to create a novel nanocomposite for photocatalytic application. Using the anthraquinone-based COP and P-GCN (1:1 ratio, PA-GCN) catalyst, the highest photodegradation efficiencies for the polymeric graphitic carbon nitride of 88.2% and 82.3% were achieved using the Fast green (FG) and Rose bengal (RB) dyes, respectively. The rate constant values of 0.032 and 0.024/min were determined for FG and RB degradation, respectively. Higher activity may be related to the incorporation of COP and PA-GCN, which act significantly well in higher visible light absorption, have superior reactive oxygen generation (ROS), and demonstrate an excellent pollutant-catalyst interaction.

Temperature Dependence of Electrical Resistance in Carbon Nanotube Composite Film during Curing Process.

Carbon nanotube (CNT) film possesses excellent mechanical and piezoresistivity, which may act as a sensor for process monitoring and reinforcement of the final composite. This paper prepared CNT/epoxy composite film via the solution dipping method and investigated the electrical resistance variation (ΔR/R0) of CNT/epoxy composite film during the curing process. The temperature dependence of electrical resistance was found to be closely related to resin rheological properties, thermal expansion, and curing shrinkage. The results show that two opposing effects on electrical resistivity occur at the initial heating stage, including thermal expansion and condensation caused by the wetting tension of the liquid resin. The lower resin content causes more apparent secondary impregnation and electrical resistivity change. When the resin viscosity remains steady during the heating stage, the electrical resistance increases with an increase in temperature due to thermal expansion. Approaching gel time, the electrical resistance drops due to the crosslink shrinkage of epoxy resin. The internal stress caused by curing shrinkage at the high-temperature platform results in an increase in electrical resistance. The temperature coefficient of resistance becomes larger with an increase in resin content. At the isothermal stage, an increase in ΔR/R0 value becomes less obvious with a decrease in resin content, and ΔR/R0 even shows a decreasing tendency.

Charge Transfer Doping of Carbon Nitride Films through Noncovalent Iodination for Enhanced Photoelectrochemical Performance: Combined Experimental and Computational Insights.

To improve the photoelectrochemical (PEC) performance of photocatalysts, the doping strategy through covalent functionalization is often adopted to adjust material electronic structures. By contrast, this work demonstrates that the noncovalent interaction in the case of iodinated graphitic carbon nitride (g-CN) film can also enhance the PEC performance. Through a facile synthesis method of rapid thermal vapor condensation (RTVC), the preparediodinated g-CN film shows a significantly improved photocurrent density (38.9µAcm-2 ), three times that of pure g-CN film (13.0µAcm-2 ) at 1.23V versus reversible hydrogen electrode. Computations reveal that the noncovalent attachment of iodine anion (I- ) on g-CN plays a crucial role in modulating the bandgap states and broadening of the visible-light absorption range as well as the charge carrier separation with the photo-induced hole confined to I- and electron to g-CN film. The fully filled valence orbitals (4d10 5s2 5p6 ) of I- determine its noncovalent attachment on the g-CN film and so do the iodine species of I3 - , I5 - , etc. This work offers a favorable synthesis method to achieve efficient doping through noncovalent charge transfer between thin film and certain dopants and provides a useful modification strategy for the establishment of multi-channel transportation of charge carriers in general photocatalysts.