Templating Agent Research Articles

Multi-scale self-templating synthesis strategy of lignin-derived hierarchical porous carbons toward high-performance zinc ion hybrid supercapacitors

Chemical activation is a common process for preparing porous carbon electrode materials of supercapacitors. Nevertheless, chemical activation approach has the disadvantages of being chemically caustic, environmentally unfriendly, and expensive. This study constitutes a multi-scale self-template approach for the preparation of lignin-derived hierarchical porous carbons (LHPCs) with high specific surface areas and excellent electrochemical performances. KCl, carbonates, and sulfates, generated in the carbonization process, play the role of multi-scale template agents for the pore-forming process. LHPCs exhibited superb electrochemical performances as electrodes of supercapacitors with alkaline and neutral sulfate electrolytes. In addition, the Zn//LHPCs hybrid supercapacitors (ZIHSCs) achieved an ultra-high energy density of 135 Wh kg−1, which is 20 times higher than symmetric supercapacitors with KOH electrolytes (6.6 Wh kg−1) and 9 times higher than symmetric supercapacitors with Na2SO4 electrolyte (14.8 Wh kg−1). This work proposes a general multi-scale self-template strategy for the synthesis of hierarchical porous carbons from sodium lignosulfonate for supercapacitor applications.

Highly effective removal of formaldehyde from aqueous solution using mesoporous ɛ-MnO2 crystals at room temperature

Without additional templating agent or surfactant, porous and sparse MnCO3 was synthesized hydrothermally from Mn2+ with a CO2-storage material (CO2SM). Through thermal decomposition of the as-synthesized MnCO3, ɛ-MnO2 crystals with good catalytic performance and stability in HCHO degradation were prepared. The optimum preparation conditions were determined by tuning the preparation conditions and carrying out response surface studies, and the resulting ɛ-MnO2 crystals could degrade 66.1% of a 10 ml 10 mg l−1 HCHO solution. After the HCHO degradation conditions were optimized, the thermodynamic data could be fitted with the Langmuir isotherm and quasi-secondary kinetic models at T = 25–50°C. The degradation mechanism of HCHO is discussed. This work provides a new strategy for the degradation of HCHO at room temperature.

Study on catalytic performance and kinetics of high efficiency CeO2 catalyst prepared by freeze drying for the synthesis of dimethyl carbonate from CO2 and methanol

• A high acid-base sites and oxygen vacancies of CeO 2 was prepared by freeze-drying. • The oxygen vacancies can be controlled by the oxygen content in the drying process. • The CeO 2 prepared by freeze drying achieves unprecedented DMC yield. • The optimal catalyst has good stability and has been recycled fifth times. • A new well-fitted kinetic model of sequential reaction was obtained. The synthesis of dimethyl carbonate (DMC) from CO 2 and methanol is an effective route of CO 2 utilization. In this work, CeO 2 nanorods prepared by hydrothermal synthesis using various drying methods were compared. Among them CeO 2 prepared by freeze drying (CeO 2 -FD) had the highest and unprecedented catalytic effects, with DMC yield of 873 mmol g -1 cat and methanol conversion of 51.6 % at 140 °C and 3.5 MPa for 4 h. All CeO 2 nanorods catalysts have been extensively characterized and the results showed that CeO 2 -FD had the largest specific surface area (90.7 m 2 g −1 ), pore volume, oxygen vacancy concentration (44.53%), and acid-base active site (189.4 vs 37.2 mmol g −1 ). The surface properties of CeO 2 nanoparticles were greatly affected by the lower absolute pressure and the use of water as a template agent in freeze-drying. For the first time, the kinetic model of sequential reaction with a dehydrating agent was deduced by Langmuir-Hinshelwood mechanism. The activation energy barrier was 20 ± 3.3 kJ mol −1 using the Arrhenius formula.

Construction and properties of an osteogenic-antibacterial functionalised drug delivery system based on hydroxyapatite microspheres

Pure hydroxyapatite (HA) has attracted much attention in the field of bone repair materials due to its strong potential for bioavailability, but its low osteogenic activity and non-bacterial inhibition limits its further application in this field. Therefore, in this study, strontium (Sr)-doped hydroxyapatite (HA-Sr) microspheres with a high specific surface area were prepared without adding a templating agent. On this basis, berberine hydrochloride (BBH), a Traditional Chinese antimicrobial agent with excellent antibacterial ability, was loaded to overcome traditional limitations and construct a material with good osteogenic activity and antibacterial capacity. A series of characterization results showed the doping of Sr did not affect the physical phase and morphology of HA but altered its chemical composition and crystallinity, and HA-Sr microspheres had good microscopic morphology and ion retardation, which laid the foundation for the subsequent improvement of the integrated capacity. In vitro cell experiments showed that Sr ions could significantly promote the differentiation of rBMSCs at a range of doping concentrations. In this study, the optimal doping concentration of 3% was systematically screened by cell proliferation assay, alkaline phosphatase staining and alizarin red staining in a small concentration range (1–7%). Subsequently, BBH was loaded with 3% Sr ion-doped HA microspheres to construct the drug loading model. And the sustained release test and antibacterial test further proved that its antibacterial performance was enhanced. The combined results of these experiments indicated that this material was successfully constructed with good osteogenic activity and antibacterial property, and its biological property was greatly improved.

Photocatalytic performance of hierarchical metal-doped framework zeolite

Hierarchical metal-doped framework zeolites are synthesized by natural silicate clay attapulgite (short for ATP) as a precursor of molecular sieve via a hydrothermal synthesis method. Under the combined action of the templating agent and the structure-directing agent, the regulation of the framework structure was carried out with metals such as titanium, zirconium, iron, and zinc to form the hierarchical heteroatom-containing zeolite. The synthesized nanocomposites systematically characterized react with azo dyes (Methylene Blue, short for MB) under light response conditions. Two types of relationship between doped metal elements and zeolite are detected as follows: a part of the metals that form oxides can be deposited on the surface or internal pores of the hierarchical zeolite, and part of the metals atoms replace the silicon atoms with the same crystal to form Si-O-Me bond, a small amount of metals sol and –OH are condensed to synthesize MFI or MEL topological structure with framework effect. The photocatalytic performance is as follows: TS-1 > TS-2 > TiO2/ZSM-5 > Fe-TiO2/ZSM-5 > ZrO2-TiO2/ZSM-5 > ZS-1 > ZnO-ZSM-5. The removal efficiency of MB is more than 90% inside 120 min with the significant photocatalytic activity of products. Moreover, the photocatalytic activity of the photocatalyst with metal forming chemical bonds into the zeolite framework is significantly better than that of the metal-supported photocatalysts. And due to the atomic radius and the photoactive sites of the metal atoms the photocatalytic activity of a single metal: Ti4+ > Zr4+ > Zn2+. For ZSM-5 zeolites doped with titanium, the single-metal doping of TiO2 is greater than the double-metal doping. In addition, the mesoporous pore channel effect of the hierarchical zeolite significantly affects the adsorption effect controls the enrichment capacity of the substrate. It was found that the hydrothermal synthesis of hierarchical heteroatom-containing zeolite has a considerable influence on the photocatalytic degradation of dyes, and can be popularized and applied in the field of dyeing wastewater treatment.

Silicalite-1 encapsulated rhodium nanoparticles for hydroformylation of 1-hexene

Hydroformylation has been applied in the chemical industry for decades to produce n-aldehydes from 1-olefins and syngas (a mixture of CO and H2). However, the difficulty of catalyst separation and harsh operating conditions of conventional homogeneous hydroformylation reactions have prompted researchers to explore heterogeneous catalytic strategies. In this work, a novel core-shell structured catalyst comprised of Rhodium nanoparticles (Rh NPs) homogeneously encapsulated in a silicalite-1 zeolite (Rh@S-1) is designed to realize a high activity in 1-hexene hydroformylation. The conversion of 1-hexene over the Rh@S-1 catalyst exhibits as high as 85.8%, and the ratio of n-heptanal to iso-heptanal reaches up to 2.5 at 90 °C. Multiple studies demonstrate that the outstanding catalytic activity over this core-shell structured catalyst can be explained by the highly active homogeneously dispersed Rh NPs and the distinguishable mass transfer effect of the unique and orderly micropores structure of silicalite-1 zeolite. Furthermore, by changing templating agent concentrations during the hydrothermal method, the size of the zeolite crystals can be easily controlled and is proven to be an essential factor affecting the hydroformylation performance.

One-step synthesis of blue emission copper nanoclusters for the detection of furaltadone and temperature

Polyvinyl pyrrolidone (PVP), playing roles as a templating agent, can be applied to prepare blue-emitting copper nanoclusters (Cu NCs@PVP) on the basis of a rapid chemical reduction synthesis method. The Cu NCs@PVP displayed a blue emission wavelength at 430 nm and the corresponding quantum yield (QY) could reach 10.4%. Subsequently, the as-synthesized Cu NCs@PVP were used for the trace analysis of furaltadone based on the inner filter effect (IFE) between Cu NCs@PVP and furaltadone, which caused the fluorescence to be effectively quenched. Additionally, this proposed determination platform based on the Cu NCs@PVP for furaltadone sensing possessed an excellent linear range from 0.5 to 100 μM with a lower detection limit of 0.045 μM (S/N = 3). Meanwhile, the Cu NCs@PVP also could be applied for the sensing of temperature. Furthermore, the practicability of the sensing platform has been successfully verified by measuring furaltadone in real samples, affirming its potential to increase fields for the determination of furaltadone.

Preparation of Nitrogen-Doped Carbon-Based Bimetallic Copper-Cobalt Catalysis Based on Deep Learning and Its Monitoring Application in Furfural Hydrogenation

In the field of catalysis, the support of the catalyst is often composed of hollow carbon materials. In order to monitor the preparation of nitrogen-doped carbon-based bimetallic copper-cobalt catalysis and its hydrogenation reaction in furfural, using m-aminophenol as the nitrogen source, formaldehyde as a carbon source, and P123 as a template agent, a nitrogen-doped bimetallic copper-cobalt mesoporous carbon catalyst Cu-Co@N-MPC-500 was synthesized by the hydrothermal method. The morphology, structure, and chemical composition of the catalyst were analyzed by means of TEM, XRD, BET, and XPS, respectively. The results show that the nitrogen-doped mesoporous carbon has a stable structure, uniform pore size distribution, and the nano-copper-cobalt particles are uniformly dispersed in the mesoporous carbon surface. Through furfural hydrogenation, the catalyst selectivity and cycle stability were discussed. Under the furfural conversion rate of 96.1%, the yield of cyclopentanone could reach 76.2%. After 5 cycles, the catalytic efficiency of the catalyst did not decrease significantly. It shows that Cu-Co@N-MPC-500 has excellent application prospects in the field of industrial production.

Compound surfactant-based emulsion method for the preparation of high-porosity alumina microspheres

Porous alumina microspheres have attracted significant attention owing to their high mechanical strength and excellent chemical and thermal stability. The emulsion method is considered as a simple and controllable method for the preparation of inorganic microspheres. However, preparing alumina microspheres with the emulsion method is challenging because the emulsification of the precursor is inhibited by the rapid hydrolysis of aluminum alkoxide. Herein, we report a new emulsion method for the preparation of high-porosity alumina microspheres using a combination of ionic and non-ionic surfactants; in this method, the compound surfactants act as a template agent to guide aluminum alkoxide to form a lamellar structure through self-assembly. The decomposition of the templating agent and transformation of the alumina crystal at a high temperature result in structural collapse and formation of lamellar pores. Compound surfactants increased the spheroidization rate of the emulsion from 47% to 63% after hydrolysis, whereas the particle size was decreased by almost half. Additionally, the morphology and porosity of the alumina microspheres were changed. With increasing anionic surfactant content, the porosity increased initially and then decreased. The porosity of the alumina microspheres reached a maximum value of 76% at the 1:1 mass ratio of the non-ionic to anionic surfactants. Heat treatment was found to change the size of lamellar pores, with the pore diameter reaching maximum value at 1300 °C. The compound surfactants also increased the compressive stress and specific surface area of the porous alumina microspheres.

Highly luminescent copper nanoclusters as temperature sensors and “turn off” detection of oxytetracycline

Polyethyleneimine (PEI), playing roles as a templating agent, has been successfully applied to prepare blue-green-emitting copper nanoclusters (Cu NCs@PEI) on the basis of a rapid chemical reduction synthesis method. Some characterization methods, such as fluorescence spectrophotometer, UV spectrophotometer, Fourier transform infrared instrument (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and fluorescence lifetime, were used for the analysis of physical, chemical and optical properties of Cu NCs@PEI. The Cu NCs@PEI displayed a blue-green emission wavelength at 485 nm and the corresponding quantum yield (QY) was 2.24%. Subsequently, the as-synthesized Cu NCs@PEI were applied for the trace analysis of oxytetracycline on the basis of the inner filter effect (IFE) and static quenching, which caused the fluorescence to be effectively quenched. Additionally, this proposed platform based on the Cu NCs@PEI for oxytetracycline sensing possessed an excellent linear range from 0.5 to 300 μM with a lower detection limit of 0.032 μM (S/N = 3) and correlation coefficient R2 of 0.9972. Surprisingly, as the temperature increased, the fluorescence intensities of Cu NCs@PEI decreased gradually. Thence, the Cu NCs@PEI could be applied for the sensing of temperature. Finally, the practicability of the detection method have been successfully verified by analyzing oxytetracycline in real samples, enlarging its applicable fields for oxytetracycline sensing.

The Effect of Surface Roughness of Magnetic Particles on the Electromagnetic Wave Absorbing Performance of Fe3O4/Multiwalled Carbon Nanotubes Hybrids

AbstractRecently, for electromagnetic wave (EMW) absorption materials, a considerable literature has testified the significant role of structures, composition, morphologies and interface in the enhancement of absorbing properties. However, far too little attention has been paid to the intensive research of surface morphology of Fe3O4 particles. The objective of this paper is to research the influence of Fe3O4 morphology on absorbing performance of Fe3O4/Multiwalled Carbon Nanotubes (MWCNTs) hybrids. The morphology of Fe3O4 particles was adjusted by the templating agent content of NH4HCO3 and NH4Ac in hydrothermal process. Of importance, we proposed to quantify the difference of Fe3O4 morphology by surface roughness. The surface roughness of three Fe3O4 particles are characterized by atomic force microscopes (AFM), which were 13.1 nm, 21.3 nm and 32.4 nm, respectively. The three absorbing hybrids were prepared via blending Fe3O4 particles with MWCNTs, and the minimum reflection loss (RLmin) of the three hybrids were −24.89 dB, −30.88 dB and −41.00 dB, respectively. The results indicated that the Fe3O4 with larger surface roughness tends to exhibit better EMW absorbing performance. It can be inferred that the greater roughness of Fe3O4 particles is an important factor to enhance EMW absorbing properties of Fe3O4/MWCNTs hybrids.

Simple fabrication of a phosphorus‐doped hierarchical porous carbon via soft‐template method for efficient CO2capture

Hierarchical porous carbons are widely used as adsorbents, catalyst supports, electrode materials, and other applications because of their high specific surface area (SSA), varied pore structure, adjustable porosity, and excellent physicochemical stability. Introducing heteroatoms such as N, P, or S, with electronegativities different from that of carbon, into the carbon skeleton can change the chemical properties of the surface and the density of the electron cloud around the carbon matrix, thus altering interactions of CO2molecules with the surface and improving CO2adsorption capacity. Therefore, doping heteroatoms in carbon materials has attracted a great amount of attention. In this paper, the template method was used with F108 (polyethylene glycol–polypropylene glycolpolyethylene glycol) as the template, resorcinol and formaldehyde solutions as the carbon sources, phosphoric acid as the phosphorus source, and KOH as the activator to prepare phosphorus‐doped hierarchical porous carbons. Through a series of characterization and CO2adsorption experiments, the influence of the amount of KOH and template agent on the pore structure of carbon materials was studied. We conclude that these phosphorus‐doped hierarchical porous carbon materials are promising CO2adsorbents.

Crystalline Covalent Triazine Frameworks with Fibrous Morphology via a Low-Temperature Polycondensation of Planar Monomer.

The morphology regulation of covalent triazine frameworks (CTFs) is a great challenge, which may be due to the difficulty in controlling its morphology by traditional synthesis methods. Herein, a general approach to fabricate morphology controllable CTFs by a mild polycondensation reaction in mixed solvents without any templating agents is reported. As a proof of concept, a type of crystalline CTFs with distinctive fibrous morphology (MS-F-CTF-1) (MS: Mixed Solvent; F: Fibrous Morphology) is developed by adjusting the ratio of mixed solvents to control the solubility of monomers, so that the nucleation, crystal growth, and subsequent self-assembly are controlled, which facilitates the formation of fibrous morphology. The resultant crystalline MS-F-CTF-1 shows uniform fibrous morphology with a diameter of about 100nm and a length of several micrometers. Notably, the fibrous morphology of CTFs can efficiently improve the photocatalytic hydrogen evolution performance, in which the hydrogen evolution rate can be boosted by about two times in comparison to block ones.

Preparation and Adsorption Properties of MCM-41 with Novel Gemini Ionic Liquid Surfactants as Template

A mesoporous molecular sieve was prepared by the hydrothermal synthesis method with symmetric Gemini surfactant 1,3-bis(hexadecyldimethylammonio)-propane dibromide, symmetric Gemini ionic liquid surfactant 1,3-bis(3-hexadecylimidazolium-1-yl) propane dibromide and self-designed asymmetric Gemini ionic liquid surfactant 1-(3-(hexadecyldimethylammonio)prop-1-yl)-3-hexadecylimidazolium dibromide as the template agent. The structure characterization results for mesoporous molecular sieves show that the material possesses a hexagonal pore structure with uniform channels. The mesoporous silica that was synthesized with self-designed asymmetric Gemini ionic liquid surfactant as the template agent possesses the largest surface area and its pore size and specific surface area are, respectively, 3.28 nm and 879.37 m2/g. The adsorption properties of the prepared MCM-41 for crystal violet were investigated, and the adsorption thermodynamics and kinetics were investigated. The results show that adsorption equilibrium can be reached under pH = 9 and 35 °C for 50 min, and the quantity of adsorption can reach up to 464.21 mg/g. The adsorption process belongs to Langmuir isothermal adsorption, conforming to second-order adsorption kinetics, and the adsorption process is an endothermic process.

Two birds with one stone: Nanocontainers with synergetic inhibition and corrosion sensing abilities towards intelligent self-healing and self-reporting coating

A smart coating integrating high-performance self-healing and sensitive self-reporting abilities was developed based on mesoporous SiO2 nanoparticles (MSN) containing both 1,10-phenanthroline-5-amine (Phen-NH2) and cetyltrimethylammonium bromide (CTAB). In the obtained MSN-PC nanocontainers, Phen-NH2 functioned as both the corrosion inhibitor and the coloration species, while CTAB acted as not only the template agent but also the corrosion inhibitor. The synthesis of MSN-PC was achieved in a facile one-step process with high encapsulation degree, and both Phen-NH2 and CTAB exhibited the accelerated release behaviors from MSN-PC triggered by pH variation. Electrochemical impedance spectroscopy (EIS) measurement and quantum chemical calculation results confirmed the synergistic inhibition effect of Phen-NH2 and CTAB against the corrosion of steel substrate and thus a self-healing effect of the damaged coating. Compared with the blank epoxy coating, the healed epoxy coating containing 4 wt% of MSN-PC could increase the low frequency impedance modulus by more than 20 times after 120 h of immersion in 3.5 wt% NaCl solution, hence suppressing the corrosion activity on the exposed metal surface. In addition to the self-healing property, the generated Fe2+ ions from the anodic site of exposed steel surface could quickly react with the released Phen-NH2 from MSN-PC nanocontainers to produce a prominent red color, achieving the timely indication of coating damage within 20 min of salt spray test. The smart coating realized sensitive corrosion visualization while significantly delaying the corrosion degradation, which holds great potential for long-term corrosion protection.

Synthesis of Porous N-doped TiO2 by Using Peroxo Sol-Gel Method for Photocatalytic Reduction of Cd(II)

Porous N-doped TiO2 photocatalyst was successfully synthesized by an environmentally friendly peroxo sol-gel method using polyethylene glycol (PEG) as a templating agent. Here, the effect of PEG addition to the aqueous peroxotitanium solutions on the structure, pore properties and photocatalytic activity of the obtained photocatalysts was systematically studied. The prepared photocatalysts were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and Brunauer-Emmett-Teller (BET). It was found that the doping of nitrogen narrows the band gap of TiO2 leading to enhance its visible-light response. The BET analysis shows that the prepared photocatalysts have a typical mesoporous structure with pore sizes of 3–6 nm. The photocatalytic activity of the prepared photocatalysts was evaluated by photocatalytic reduction of Cd(II) in an aqueous solution under visible light irradiation. The results show that porous N-doped TiO2 with the optimal PEG addition had the highest Cd(II) reduction of 85.1% after 2.5 h irradiation in neutral aqueous solution. This significant improvement in photocatalytic activity of the prepared photocatalysts was mainly attributed to the synergistic combination of N doping and porous structure, which could actively increase the catalytic active site of this photocatalysts. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Research Progress on Polyaniline-Ionic liquids for Long Cycle-Stable Supercapacitors with High Capacitance

Ionic liquids have been used either as polymerization medium or as electrolytes for polyaniline (PANI) electrodes to produce long cycle-stable supercapacitors with high capacitance. As a polymerization medium, ionic liquids play the role of a soft template agent and induce the formation of nanostructured PANI morphology. Nanorod, nanowire, or spherical PANI morphology has been obtained in ionic liquids instead of agglomerated particles resulted in the conventional media. The well-defined one-dimensional PANI morphology ensures a short charge transfer distance in the PANI materials and low contact resistance between PANI and electrolyte interfaces. The efficiency of ionic liquids as a soft template agent is related to their structure as well as to their proportion in the reaction medium. As electrolytes, “neat” ionic liquids provide low but stable specific capacitance of PANI over more than hundreds of cycles. Binary mixtures of ionic liquids and solvents (e.g. acetonitrile, water) have increased both the specific capacitance and the capacitance retention of PANI compared with the performances resulting in the conventional aqueous acid electrolytes. Using ionic liquids to carry out both the synthesis and the electrochemical characterization of PANI is an effective approach to improve PANI cycle life. The key parameter is to choose the convenient ionic liquids. This review covers the most significant studies conducted on PANI/ionic liquids for supercapacitor applications.

Optimizing porous structure of carbon electrodes for temperature-independent capacitance at sub-zero temperatures

Fundamental understanding of ion transport in porous carbon materials with different pore size is of great importance for carbon electrode-based supercapacitors to realize the ability of rapid charge/discharge process and high energy density at broad operating temperatures. Herein, hierarchically porous carbon frameworks are synthesized as model electrodes by using a tunable one-pot strategy in the presence of salt template and pore-forming agent. Density functional theory calculation reveals that the size of micropores can significantly influence the solvation energy and desolvation time of electrolyte, thereby affecting the ion transport kinetics and the specific capacitance of porous carbon electrode, particularly at low temperatures. The accordingly optimized carbon electrode material with rational micropore size and interconnected hierarchical pores exhibits the specific capacitance of 200 and 245F·g−1 at −40 and 60 °C, respectively. The as-fabricated symmetric supercapacitor can deliver an exceptional energy density of 63.4 Wh·kg−1 under power density of 1.5 kW·kg−1 at −40 °C. In addition, the device has the ability for fast charge/discharge process at low temperature, as evidenced by the energy density of 34.3 Wh·kg−1 under an ultrahigh power density of 37.5 kW·kg−1 at − 40 °C.

Effect of hierarchical porous MOF-199 regulated by PVP on their ambient desulfurization performance

Hierarchical porous MOF-199 with small crystal sizes was synthesized via PVP (Polyvinylpyrrolidone) regulation in an aqueous system, in which PVP acted as nucleating, coordination and template agent. The ambient desulfurization performance of the obtained MOF-199 regulated with different PVP amounts toward CH3SCH3 and H2S and their structure-performance relationship were systematically studied. It is found that CH3SCH3 was first chemisorbed on the surface of the adsorbent in a monolayer by weak coordination and then physisorbed in multilayers. This whole process was reversible and the structure of MOF kept stable. The hierarchical pores plus the small crystal size of MOF-199-P1, especially to the latter, endowed the uptake for CH3SCH3 reaching 88.1 mg S/g, 42% higher than that of pristine MOF-199. However, the adsorption of H2S by MOF-199 is chemical and the collapse of the MOF structure was observed. The hierarchical porous structure helped H2S access as many active sites as possible before the blockage of pores caused by the structural damage. As a result, MOF-199-P2 achieved the optimum breakthrough capacity of 74.3 mg S/g towards H2S, 34 % higher than the bare MOF-199. This study provides new strategies and insights for the adsorption process between sulfide and adsorbents in different reaction modes.

Modulation of Cerium Carbonate Crystal Growth by Polyvinylpyrrolidone using Density Functional Theory.

Cerium carbonate crystal morphology is predicted using density functional theory (DFT) simulations in this paper. In the nucleation phase, the ketone group in polyvinylpyrrolidone (PVP) will preferentially bind to Ce3+ to form complexes and provide heterogeneous nucleation sites for the system, prompting the nucleation of cerium carbonate crystals. In the growth stage, due to the adsorption of PVP, the probability of (120) crystal plane appearing in the equilibrium state is the greatest, resulting in the formation of hexagonal flake cerium carbonate crystals with (120) crystal plane as the oblique edge. Experimentally, hexagonal sheet cerium carbonate crystals were successfully prepared using PVP as a template agent. Therefore, DFT can be used to predict the morphology of cerium carbonate crystals, which not only elucidates the growth mechanism of cerium carbonate crystals, but also greatly reduces the experimental cost.