Environment-related Applications Research Articles

Exploring the impact of Anions, Alkyl group and confinement effect in ionic liquid @ UiO-66(Zr) MOF: A DFT study

Metal organic frameworks (MOFs) have emerged as a strong research material due to their exceptional porosity and tunable functional nature. MOF structures consist of metal nodes with organic linker, which can be functionalized depending on the required application. With the tunable properties, it has wide range of applications in energy, environmental and therapeutic approaches. Nevertheless there are several factors which can affect their performance such as lower affinity towards target molecules, chemical and thermal stability etc. To counter these issues several studies have been devoted on functionalizing the MOF. In this work, we have considered UiO-66 (University of Oslo-66) MOF because of its exceptional thermal and chemical stability with a series of versatile ionic liquids (ILs). The selected ILs are 1-ethyl-3-methylimidazolium ([C2MIm]+) and 1‑butyl‑3-methylimidazolium ([C4MIm]+) cations with various anions [X]−, where X = acetate (OAc), tetrafluroborate (BF4), dicyanamide (DCA), nitrite (NO2) and chloride (Cl) anions. These ILs have been impregnated in tetrahedral (∼10 Å) and octahedral (∼16 Å) pores of UiO-66 structure. First principle density functional theory (DFT) approach is used to study the structure, stability, spectral properties and charge transfer between IL/UiO-66 interfaces. Our calculations suggest that, IL does not affect the structure of UiO-66 surface. The anion and the alkyl group in the cations play a vital role in the stability of the complexes. Furthermore, confinement effect influence the stability of the complexes, irrespective nature of anion and cation. Electron density and charge transfer analyses reveal that anions have profound liking towards MOF because of having high electronegative atoms. Our study will help to understand the molecular level interaction between IL@MOF interface, and these composite can be utilized for the energy and environment related applications.

Rational design of amine-terminated terephthalate in bismuth metal-organic framework for boosting sunlight-catalytic removal of organic pollutants

BackgroundBismuth-based metal-organic frameworks (Bi-MOFs) have garnered significant interest in energy and environment-related applications. Here, we report a Bi-MOFs synthesized by amino terephthalic acid (Bi-MOF (ATP)) and Bi-MOF (CAU-17), the developed Bi-MOF (ATP) shows exceptional photocatalytic efficiency in degrading both cationic and anionic pollutants, crystal violet (CV) fast green (FG) under solar light exposure. MethodsThe CAU-17 and Bi-MOF (ATP) were prepared by the solvothermal method. However, only the Bi-MOF (ATP) ability to absorb visible spectrum and degradation of pollutants can be attributed to several factors, including the diminished particle sizes, mitigated recombination of charge carriers, oxidation of nitrogen during photocatalytic reactions, and a favorable bandgap of positioning within the visible spectrum. Significant findingsThe Mott-Schottky plot and electron paramagnetic resonance analyses confirmed a Bi-MOF (ATP) generated free radicals (·O2‾). The remarkable photocatalytic degradation of CV and FG can achieve 92 % and 95 %, respectively. Notably, the catalyst retains robust stability throughout reusability assessments, maintaining its degradation efficiency without compromising the integrity of its crystalline structure and morphology. This study sheds light on the promising potential of Bi-MOFs (ATP) as effective photocatalysts for pollution under solar light.

Scalable confined-space microwave heating strategy enables the rapid preparation of N/O co-doped activated carbons with high gas capture capacity

Heteroatom doping is essential for enhancing the performance of activated carbons (ACs) in various environmental-related applications. Herein, a scalable confined-space microwave heating (CSMH) strategy is proposed and demonstrated to achieve minute-level fast preparation of N/O co-doping ACs with well-developed porosity. The introduction of confined space prevents the escape of nitrogenous and oxygenous volatiles, enabling the sufficient reaction for heteroatom doping. Therefore, the nitrogen content of MWC-0.5 (6.0 at.%) is higher than that of MW-0.5 (3.5 at.%) and CH-0.5 (4.3 at.%). This causes a nearly 50 % reduction in the consumption of nitrogenous reagents. Moreover, through CSMH strategy, N/O co-doped ACs (6.0 at% and 8.1 at% for N and O, respectively) with high pore volume (0.53 cm3 g−1) can be acquired to achieve an excellent adsorption performance for toluene (0.31 g g−1) and CO2 (3.97 mmol g−1 at 25 °C and 1 bar) and outstanding CO2/N2 selectivity (189 at 0.02 bar). This work for the first time develops a scalable confined-space N/O co-doped strategy for enhancing the chemical activity of ACs with low-spend nitrogenous reagents.

Environmental-related applications of ZnO nanopowders: Photocatalytic activity and photoluminescence response to ethanol

Zinc oxide (ZnO) and copper-doped zinc oxide (ZnO:Cu) nanopowders were synthesized via solvothermal methods using methanol and hexamethylenetetramine (HMTA). Undoped ZnO nanopowders underwent calcination in O2-rich and H2-rich atmospheres at 600 °C. Samples were studied by scanning electron microscopy, Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD), and Raman, photoluminescence (PL) and UV–vis absorbance spectroscopies. The doping and calcinations led to a reduction of the optical bandgap of the nanopowders, while their structure remained hexagonal wurtzite with some changes in lattice parameters and average nanoparticle sizes. The Cu2+ doping led to a BET surface area and violet PL component increase. Samples were also examined for environmental related applications, namely as photocatalyzers for dye degradation and as ethanol optical sensors. For photocatalytic activity in methylene blue degradation under UV, H2-rich calcined powders excelled, with a rate constant of −0.076 min−1, surpassing −0.057 min−1 (ZnO:Cu), −0.056 min−1 (O2-rich calcination), and −0.041 min−1 (as-grown ZnO). We propose that this improvement can be attributed to the formation of ZnO/Zn interfaces stemming from the reduction of surface interstitial zinc by H2 during calcination, in addition to the observed reduction of the ZnO bandgap. The doped nanopowders PL also showed excellent response when exposed to ethanol vapor.

Carbon nitride with water soluble ability: Enhanced oxygen species interphase mass transfer for homogenous photocatalytic water purification

Heterogeneous catalysis has been considered a promising way for waste purification, however the catalytic performances of the heterogeneous-based systems are still unsatisfactory, mainly due to the limited active sites exposure and sluggish reactants mass transfer. In this study, we propose a conceptual carbonitride-based quasi-homogeneous catalytic system, exhibiting remarkable photocatalytic activity toward organic pollutants degradation and pathogenic bacteria inactivation. We verify that downsizing carbonitride into nanodot level and modifying the material with hydrophilic groups can endow it with water soluble ability, forming a quasi-homogeneous catalytic system to maximize the active sites exposure and minimize the reactants mass transfer resistance for high-efficient water purification. As a result, the as-established quasi-homogeneous photocatalytic system exhibits abundant surface-active sites and reactants mass transfer efficiencies that allows remarkable O2 reduction for ROS generation. In addition, the treated water containing the functionalized carbonitride is found capable of driving the fast flocculate of suspended substance, which helps to build a well water decontamination and suspended substance removal water purification nexus for practical applications. The work demonstrated here sheds new light in designing high-efficient homogeneous catalytic system for energy and environmental related applications.

Mesopore and macropore engineering in metal–organic frameworks for energy environment-related applications

The fabrication strategies of mesopores and macropores in metal–organic frameworks (MOFs) and their emerging applications are summarized. In addition, the challenges and future perspectives of pore engineering in MOF design are also indicated.

Four-in-one strategy to boost the performance of 3-dimensional MoS2 nanostructures for industrial effluent treatment and hydrogen evolution reactions

Two-dimensional (2D) molybdenum disulfide (MoS2) has gained enormous attention as a photocatalytic material due to its extraordinary optical, electrical, and chemical properties which are highly tunable by engineered control of its 2D layers orientation. However, high carrier recombination rates in pristine MoS2 nanostructures hinder their practical applications as an efficient catalyst. There is an upsurge of research on developing new strategies to improving its photocatalytic actions for environmental remediation. One approach is to design MoS2 nanostructures with vertically aligned layer-structures or cross-linking 3-dimensional flower-like morphologies, which exhibit ultrahigh-density 2D edge sites that offer tremendous chemical reactivity. Another challenge is to obtain its highly active metallic 1 T phase by functional design of intrinsic structures without sacrificing its ambient stability. Herein, we reported highly active and mix-phased 1 T/2 H MoS2 nanostructures through elegant synthesis management. By regulating reaction kinetics with the assimilation of NH4+ ions and water molecules, tunable surface morphology from nano wrinkles to nanoflowers was achieved. The morphology regulations induced modifications in the surface areas of final products which were calculated as 64.3 m2g−1, 114.3 m2g−1, and 219.7 m2g−1, respectively. Moreover, the bandgaps were significantly lowered from 2.13 eV to 1.93 eV and 1.85 eV. This four-in-one strategy efficiently boosted photodegradation of organic pollutants up to 94% in less than 20 min with excellent cyclic reproducibility for seven cycles. In addition, exceptional hydrogen evolution reaction (HER) performance with a very low overpotential of 145 mV and Tafel slope of 81.4 mV/dec was recorded. The results obtained in this work demonstrated excellent suitability of these materials as catalysts in environment related applications such as organic dye removal and for efficient hydrogen production.

Conjugated Microporous Polymers Based on Octet and Tetratopic Linkers for Efficient Iodine Capture.

Radioactive iodine from nuclear waste poses a huge threat to public safety and raises concerns about environmental pollution. There is thus a growing demand for developing novel adsorbents for highly effective iodine capture. In this work, we design and synthesize three novel conjugated microporous polymers, namely, TPE-PyTTA-CMP, TPE-TAPP-CMP, and TPE-TPDA-CMP, which are constructed by an imidization reaction based on octet and tetratopic linkers. The iodine vapor adsorption experiments show that the three CMPs have an excellent iodine adsorption capacity as high as 3.10, 3.67, and 4.68 g·g-1 under 348 K and ambient pressure conditions, respectively. The adsorbed iodine in the CMPs can be released into methanol in a dramatically rapid manner, and their excellent iodine adsorption performance can still be maintained after multiple cycles. In addition, the CMPs demonstrate good adsorption performance in an n-hexane solution of iodine, and the kinetic experimental data follow the pseudo-second-order model. The hierarchical porosity, extended π-conjugated skeleton, and rich electron-donor nitrogen sites of the CMPs could contribute to their excellent iodine adsorption performance. The knowledge information obtained in this work could open up new possibilities for designing novel CMPs targeting a wide range of environment-related applications.

(Invited) Coupling Metal-Organic Framework with Oxide Photocatalyst for Selective Photoredox Reactions

Oxide photocatalyst is one of the major groups of photoactive semiconductors capable of facilitating useful photoredox reactions for a variety of energy and environmental-related applications. The intrinsic optical and electronic properties of oxide photocatalysts encounter a number of limitations. Often, the wide band gap and inferior photoexcited charge transportation within oxide semiconductors are highlighted. Wide band gap limits the light absorption while inadequate charge transport properties such as low charge mobility and short lifetime can only afford mild photoactivities. Strategies have been formulated to improve the performance of these semiconductors in order to bridge the gap for practical use. Among many existing strategies, coupling oxide photocatalysts with metal-organic framework (MOF) has gained attention in the community as one potential method to improve performance (e.g. higher light absorption, better product yield, prolonged stability and etc). Attaching photoactive MOFs onto or “doping” metallic element into oxide photocatalyst may extend the light absorption of the composite materials. Improved product yield is, more often, attributed to the adsorption capacity of MOFs towards reactant, which bring about the localised concentration of reactants adjacent to active sites of photocatalyst. Encapsulation of oxide photocatalyst by MOFs can suppress the undesirable side reactions (such as preventing Cu2O from direct contact with moisture) to prolong the stability of oxide photocatalyst.In this presentation, in addition to the above mentioned advantages of MOFs, the role of MOFs in tuning the selectivity of product formation will also be examined and discussed. Figure 1 shows an example of improved selective oxidation of ethanol to form acetaldehyde using ZIF-8 encapsulated ZnO. Selectivity towards acetaldehyde has been improved from ~79% to ~92% with stable photocatalytic activity.1 In another work, Cu2O covered by Cu-MOF has afforded selective CO2 photoreduction to CH4.2 We believe there is charge interaction between the oxide photocatalyst and the adjacent MOF structure. Transfer of photoexcited electrons from the conduction band of Cu2O to the LUMO level of non-excited wide band gap Cu-MOF has been indicated using time-resolved photoluminescence. Because photocatalytic reactions are the results of electron transfer between photocatalyst and reactants, the presence of photocharge interplay between oxide photocatalyst and MOFs may provide new room for exploration as it has demonstrated significant influence in the selectivity of product formation. Figure 1. Example of improved product selectivity by incorporating MOFs to oxide photocatalyst. The left figure indicates the improved formation of acetaldehyde from photocatalytic ethanol oxidation. The right figure shows the reasonable stability of the MOF-oxide photocatalyst under illumination. Reference: H. Wu, T. H. Tan, R. Liu, H. -Y. Hsu, Y. H. Ng, Selective Ethanol Oxidation to Acetaldehyde on Nanostructured Zeolitic Imidazolate Framework-8-wrapped ZnO Photothermocatalyst Thin Films, Solar RRL 2021, 5, 2000423.H. Wu, X. Y. Kong, X. Wen, S. –P. Chai, E. C. Lovell, J. Tang, Y. H. Ng, Metal-Organic Framework Decorated Cuprous Oxide Nanowires for Long-lived Charges Applied in Selective Photocatalytic CO2 Reduction to CH4. Angew. Chem. Int. Ed. 2021, 60, 8455-8459. Figure 1

Computational Examination of Heat and Mass Transfer Induced by Ternary Nanofluid Flow across Convergent/Divergent Channels with Pollutant Concentration

Studying waste discharge concentration across a convergent/divergent channel is essential in environmental-related applications. Successful environmental administration must understand the behavior and concentration of waste contaminants released into these channels. Analyzing waste discharge concentrations aids in determining the efficacy of treatment techniques and regulatory controls in lowering pollutant scales. Because of this, the current analysis examines the ternary-based nanofluid flow across convergent/divergent channels, including non-uniform heat source/sink and concentration pollutants. The study also concentrates on understanding the movement and heat transmission characteristics in ternary-based nano-liquid systems with divergent and convergent channels and maximizing the ternary nanofluid flow’s effectiveness. The equations representing the flow, temperature, and concentrations are transformed into a system of ODEs (ordinary differential equations) and are obtained by proper similarity variables. Further, solutions of ODEs are gathered by using the Runge Kutta Fehlberg 4-5 (RKF-45) method and shooting procedure. The significant dimensionless constraints and their impacts are discussed using plots. The results mainly focus on improving local and external pollutant source variation will enhance the concentration for the divergent channel while declining for the convergent channel. Adding a solid fraction of nanoparticles will escalate the surface drag force. These findings may enhance heat management, lessen pollutant dispersion, and enhance the circulation of nanofluid systems.

Nanoconfinement enabled non-covalently decorated MXene membranes for ion-sieving

Covalent modification is commonly used to tune the channel size and functionality of 2D membranes. However, common synthesis strategies used to produce such modifications are known to disrupt the structure of the membranes. Herein, we report less intrusive yet equally effective non-covalent modifications on Ti3C2Tx MXene membranes by a solvent treatment, where the channels are robustly decorated by protic solvents via hydrogen bond network. The densely functionalized (-O, -F, -OH) Ti3C2Tx channel allows multiple hydrogen bond establishment and its sub-1-nm size induces a nanoconfinement effect to greatly strengthen these interactions by maintaining solvent-MXene distance and solvent orientation. In sub-1-nm ion sieving and separation, as-decorated membranes exhibit stable ion rejection, and proton-cation (H+/Mn+) selectivity that is up to 50 times and 30 times, respectively, higher than that of pristine membranes. It demonstrates the feasibility of non-covalent methods as a broad modification alternative for nanochannels integrated in energy-, resource- and environment-related applications.

Tunability of bandgap from UV to visible region by transition metal ion implantation in CeO2 and their electronic structures

The present report examines the tunability of optical band gap by 150 keV Fe ion implantation in cerium oxide (CeO2) thin films and their electronic structures. X-ray diffraction (XRD) confirms the stable FCC structure and these films lose their crystalline nature with increasing ion fluences. Atomic force microscopy (AFM) shows the morphology changes. Raman measurement exhibits the presence of defect states. UV–vis spectroscopy reveals that the optical band gap reduces from 3.14 eV to 2.70 eV. These results are well correlated with the electronic structure studies from the x-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS). The XPS indicates the existence of Ce3+ due to the replacement of Fe3+ which reduces the Ce4+ to Ce3+ ions. XAS at the Ce-M4,5 edge reveals the change in Ce4+→Ce3+ with Fe ion fluence and the O-K edge spectra show that the vacancies are introduced after Fe ion implantation. The edge shifting of the O-K edge confirmed the presence of Ce4+-VO-Ce3+ and Ce3+-VO-Fe3+ networks in Fe-implanted thin films. This reversible ability enables the CeO2-based nanomaterial for energy and environmental-related applications.

Polysulfone-based mixed matrix membranes loaded with a multifunctional hierarchical porous Ag-Cu dendrites@SiO2 core-shell nanostructure for wastewater treatment

Eliminating pollutants from wastewater is a crucial approach to securing the global water supply. It is well known that membrane purification technologies are remarkably attractive due to their high efficacy and low energy consumption. The neat polysulfone (PSF) polymer membranes, though, are prone to be fouled by organic pollutants, causing pore blockage and waned separation performance. We herein report and describe the rational design of a hierarchical porous Ag-Cu dendrites@SiO2 core-shell nanostructure/PSF mixed matrix membranes (MMMs) by coupling heterogeneous dendritic Ag-Cu@SiO2 core-shell nanostructure with PSF polymer matrix using facile phase inversion method for efficient separation of the protein (Bovine Serum Albumin; BSA) and Rose Bengal (RB) dye removal. Besides, for the first time, a theoretical mapping of molecular electrostatic potential (MESP) maps for chemical structure has been used for studying the interaction between the compounds (membrane moieties and pollutants). Practically, the SiO2 nanoparticles provide excellent hydrophilicity causing a sequential efficient, antifouling protein and dye separation with an outstanding rejection rate of over 96 % for both BSA and RB. In addition, the porous hierarchical scaffold formed from the hydrophilic Ag-Cu nanosheets embedded with SiO2 nanoparticles greatly assists the rapid permeation of water with a high flux rate of up to 50 L m−2 h−1 bar−1 for pure water. Furthermore, the hydrophilic nature of Ag and Cu nanoparticles also renders this membrane with a high removal capability for dye blocking enabling it to remove soluble pollutants in molecular dimensions as well. This design strategy not only provides an outstanding membrane for water purification but also sheds light on the design of multi-purpose functional membranes for a variety of energy and environment-related applications.

Progress reports of metal-phenolic network engineered membranes for water treatment

Metal-phenolic network (MPN) is a kind of supramolecular material formed by the complexation of metal ions and organic ligands, and is widely used due to its extensive adhesive properties and simple operation methods. At present, MPN has been successfully applied in the surface modification of separation membrane materials, but there is still a lack of comprehensive reviews of separation membranes constructed by MPN, including construction methods and different applications. This paper emphasizes the formation mechanism and characteristics of MPN and MPN-based engineering strategies for the fabrication of multifunctional MPN-engineered membranes. The application of MPN-engineered membranes in water treatment is mainly introduced, including separation (molecular sieving and oil–water separation), catalysis (degradation of organic pollutants), and adsorption (dye adsorption and heavy metal adsorption). Given the limitations of current MPN functional membranes, the prospects for developing ultra-thin and durable MPN-engineered functional membranes are presented. This review has reference significance for the fields of water treatment and other energy and environment-related applications.

Recent Advances in Porous Carbon Materials as Electrodes for Supercapacitors.

Porous carbon materials have demonstrated exceptional performance in various energy and environment-related applications. Recently, research on supercapacitors has been steadily increasing, and porous carbon materials have emerged as the most significant electrode material for supercapacitors. Nonetheless, the high cost and potential for environmental pollution associated with the preparation process of porous carbon materials remain significant issues. This paper presents an overview of common methods for preparing porous carbon materials, including the carbon-activation method, hard-templating method, soft-templating method, sacrificial-templating method, and self-templating method. Additionally, we also review several emerging methods for the preparation of porous carbon materials, such as copolymer pyrolysis, carbohydrate self-activation, and laser scribing. We then categorise porous carbons based on their pore sizes and the presence or absence of heteroatom doping. Finally, we provide an overview of recent applications of porous carbon materials as electrodes for supercapacitors.

Database Design for Double-Linker Metal–Organic Frameworks

Most metal–organic frameworks are composed of a single organic linker bridging between two different metal clusters. On the other hand, “double-linker” MOFs, which can be formed by bridging two different metal clusters with two organic ligands, are comparatively rare. In this work, we devise an algorithm that can computationally generate these double-linker MOFs and use our strategy to build a large database of hypothetical double-linker MOFs. These MOFs tend to have large pore volumes compared to other experimentally synthesized MOFs and can serve to expand the set of potential MOFs for various energy and environmental-related applications.

Construction of TiO2-x Confined by Layered Iron Silicate toward Efficient Visible-Light-Driven Photocatalysis-Fenton Synergistic Removal of Organic Pollutants.

The photocatalysis-Fenton synergistic reaction has great potential for water purification but generally suffers from unsatisfactory electron transfer due to an undesirable interface structure. Herein, we developed a novel heterojunction of oxygen vacancy-rich TiO2-x confined in the layer space of a synthetic montmorillonite-like iron silicate (denoted as TiO2-x/FeMMT) that addresses the issue mentioned above. Two-dimensional layered montmorillonite-like silicates in heterojunctions as a support not only provided more active sites for the reaction but also induced oxygen vacancies in TiO2-x through interfacial effects to enhance the visible-light harvesting ability. Notably, such loading TiO2-x as an electron donor accelerated the Fe(III)/Fe(II) redox cycling and facilitated the effective activation of H2O2, while Fe(III) in the montmorillonite-like silicate as electron trap sites greatly improved the separation of photogenerated electron-hole pairs. More interestingly, the internal electric field and oxygen vacancies (Vo) existing at the interface realized the directional migration of photogenerated electrons and improved the energy band structure of the heterojunction, respectively. Eventually, the TiO2-x/FeMMT composites exhibited superior photocatalysis-Fenton performance toward degradation removal of phenol, dinotefuran (DIN), and sulfamethoxazole (SMX) under visible-light irradiation. This paves the way for the rational design of high-efficiency heterojunction catalysts based on layered silicates for environment-related applications.

Trace to the Source: Self‐Tuning of MOF Photocatalysts

AbstractBenefitting from ultra‐high porosity, large specific surface area (SSA), and rich active sites, metal–organic frameworks (MOFs) have emerged as a star material in energy and environment related applications, especially in photocatalysis. In comparison with conventional photocatalysts, MOFs can be customized in terms of electronic structure, photo‐responsiveness, and morphological dimensions by rational design, which means that MOFs eliminate the need for other species to achieve enhanced photocatalytic performance, such as metals, compounds, and polymers, which may introduce extra costs, be time‐consuming, be multi‐phase, or have an unclear mechanism. Most previous review works related to MOF photocatalysis have mixed self‐tuning and assisted‐tuning, which often gives an incomplete understanding. In this work, the self‐tunning of MOFs by analyzing component (as clusters, ligands, and inclusions), defect (defect engineering, as linkers, clusters, and oxygen vacancies (OVs), and crystal (as facets, dimensions, and amorphization) is summarized. Then, outstanding examples of these strategies applied to water redox, CO2/N2 reduction, organic conversion, and environmental treatment are discussed. Finally, the opportunities and challenges faced in the self‐tuning of MOFs are analyzed from different perspectives. This paper is a comprehensive and systematic review on the self‐tuning of MOFs to enhance photocatalytic activity.

Enhancing Hydrogen Sulfide Detection at Room Temperature Using ZIF-67-Chitosan Membrane.

Developing new materials for energy and environment-related applications is a critical research field. In this context, organic and metal-organic framework (MOF) materials are a promising solution for sensing hazardous gases and saving energy. Herein, a flexible membrane of the zeolitic imidazole framework (ZIF-67) mixed with a conductivity-controlled chitosan polymer was fabricated for detecting hydrogen sulfide (H2S) gas at room temperature (RT). The developed sensing device remarkably enhances the detection signal of 15 ppm of H2S gas at RT (23 °C). The response recorded is significantly higher than previously reported values. The optimization of the membrane doping percentage achieved exemplary results with respect to long-term stability, repeatability, and selectivity of the target gas among an array of several gases. The fabricated gas sensor has a fast response and a recovery time of 39 s and 142 s, respectively, for 15 ppm of H2S gas at RT. While the developed sensing device operates at RT and uses low bias voltage (0.5 V), the requirement for an additional heating element has been eliminated and the necessity for external energy is minimized. These novel features of the developed sensing device could be utilized for the real-time detection of harmful gases for a healthy and clean environment.

Supramolecular assembly-derived carbon-nitrogen-based functional materials for photo/electrochemical applications: progress and challenges

Supramolecular chemistry during the synthesis of carbon-nitrogen-based materials has recently experienced a renaissance in the arena of photocatalysis and electrocatalysis. In this review, we start with the discussion of supramolecular assemblies-derived carbon-nitrogen-based materials’ regulation from the aspect of morphology, chemical composition, and micro/nanostructural control. Afterwards the recent advances of these materials in energy and environment related applications, including degradation of pollutants, water splitting, oxygen reduction reactions, CO₂ reduction reactions along with organic synthesis are summarized. The correlations between the structural features and physicochemical properties of the carbon-nitrogen-based materials and the specific catalytic activity are discussed in-depth. By highlighting the opportunities and challenges of supramolecular assembly strategies, we attempt an outlook on possible future developments for highly efficient carbon-based photo/electrocatalysts.