Simple Reaction Research Articles

Establishment of a Cas12a-Based Visual Detection Method Involving PMNT for the Colletotrichum gloeosporioides Species Complex.

Strawberry anthracnose, caused by Colletotrichum spp., is a devastating disease that significantly reduces strawberry yield and quality. This study aimed to develop a simple diagnostic method to detect infection by the Colletotrichum gloeosporioides complex (CGSC), the most predominant and virulent Colletotrichum species complex causing strawberry anthracnose in China. In this study, a Cas12aVIP diagnostic method was developed for the rapid detection of CGSC in strawberry seedlings. This method targets the β-tubulin gene and combines recombinase polymerase amplification (RPA), the CRISPR/Cas12a system, and a cationic-conjugated polythiophene derivative [poly(3-(3'-N,N,N-triethylamino-1'-propyloxy)-4-methyl-2,5-thiophene hydrochloride) (PMNT)] mixed with single-stranded DNA (ssDNA). This method shows high sensitivity (ten copies per reaction) and no cross-reactivity against related pathogens. The entire procedure, from sample to result, can be completed within 50 min, including simplified DNA extraction (15 min), RPA reaction (37°C for 20 min), CRISPR/Cas12a detection (37°C for 10 min), and visual detection by the naked eye (1-2 min). Furthermore, the Cas12aVIP assay successfully detected CGSC in naturally infected strawberry seedling samples in field conditions. Asymptomatic infected plants and plant residues have been identified as primary inoculum sources for CGSC. This method enables visible detection without the need for expensive equipment or specialized technical skills, thereby offering an efficient and straightforward approach for detecting CGSC in strawberries. The newly developed detection method can be used to promote healthier strawberry production.

Roles of network topology in the relaxation dynamics of simple chemical reaction network models

Understanding the relationship between the structure of chemical reaction networks and their reaction dynamics is essential for unveiling the design principles of living organisms. However, while some network-structural features are known to relate to the steady-state characteristics of chemical reaction networks, mathematical frameworks describing the links between out-of-steady-state dynamics and network structure are still underdeveloped. Here, we characterize the out-of-steady-state behavior of a class of artificial chemical reaction networks consisting of the ligation and splitting reactions of polymers. Within this class, we examine minimal networks that can convert a given set of sources (e.g., nutrients) to a specified set of targets (e.g., biomass precursors). By exploring the dynamics of the models with a simple setup, we find three distinct types of relaxation dynamics after perturbation from a steady-state: exponential-, power-law-, and plateau-dominated. We computationally show that we can predict this out-of-steady-state dynamical behavior from just three features computed from the network’s stoichiometric matrix, namely, (1) the rank gap, determining the existence of a steady-state; (2) the left null-space, being related to conserved quantities in the dynamics; and (3) the stoichiometric cone, dictating the range of achievable chemical concentrations. We further demonstrate that these three quantities relates to the type of relaxation dynamics of combinations of our minimal networks, larger networks with many redundant pathways, and a real example of a metabolic network. The relationship between the topological features of reaction networks and the relaxation dynamics presented here are useful clues for understanding the design of metabolic reaction networks as well as industrially useful chemical production pathways.

Widespread biochemical reaction networks enable Turing patterns without imposed feedback

Understanding self-organized pattern formation is fundamental to biology. In 1952, Alan Turing proposed a pattern-enabling mechanism in reaction-diffusion systems containing chemical species later conceptualized as activators and inhibitors that are involved in feedback loops. However, identifying pattern-enabling regulatory systems with the concept of feedback loops has been a long-standing challenge. To date, very few pattern-enabling circuits have been discovered experimentally. This is in stark contrast to ubiquitous periodic patterns and symmetry in biology. In this work, we systematically study Turing patterns in 23 elementary biochemical networks without assigning any activator or inhibitor. These mass action models describe post-synthesis interactions applicable to most proteins and RNAs in multicellular organisms. Strikingly, we find ten simple reaction networks capable of generating Turing patterns. While these network models are consistent with Turing’s theory mathematically, there is no apparent connection between them and commonly used activator-feedback intuition. Instead, we identify a unifying network motif that enables Turing patterns via regulated degradation pathways with flexible diffusion rate constants of individual molecules. Our work reveals widespread biochemical systems for pattern formation, and it provides an alternative approach to tackle the challenge of identifying pattern-enabling biological systems.

Preparation and evaluation of polymeric ionic liquid functionalized microparticles as the efficient adsorbent for pipette tip solid phase extraction of sulfonamides

Sulfonamides (SAs) residues are commonly found in environmental samples, which is highly concerning for public safety and environmental protection. The detection of SAs is quite important but challenging. In this work, a kind of polymeric ionic liquid functionalized microparticles (PIL-FM) was synthesized via a simple free radical polymerization reaction, and applied as the adsorbent for pipette tip solid phase extraction (PT-SPE) of three SAs from river water, milk powder and honey samples. The adsorption performance of PIL-FM on SAs were evaluated using adsorption kinetics and adsorption isotherms, and the results showed that PIL-FM had the best selectivity for SMZ with the maximum adsorption capacity was as high as 45.05 mg·g−1. The extraction process was optimized and the adsorption mechanism was preliminarily discussed. PIL-FM has the excellent selectivity for SAs mainly because of the strong π-π interaction, and the electrostatic repulsion between them in the elution step also has a positive impact. Under optimal conditions, combined with HPLC, this PT-SPE method had wide linearity (0.2–100 μg·L−1, R2 ≥ 0.9998) and low limits of detection (0.06–0.08 μg·L−1). The intra-day and inter-day repeatability were found to be 3.7 %–4.6 % and 4.5 %–6.2 %, respectively. The suggested PT-SPE method is simple, low cost, rapid, and efficient to extract SAs, and can be applied for the monitoring of SAs residues in the aquatic environment and in food.

Modeling of Spray Combustion and Heat Transfer of MMH/N2O4 in a Small Rocket Engine Using Different Mechanisms

Although various hypergolic propellants like MMH/N2O4 (monomethylhydrazine/dinitrogen tetroxide) are widely used in small rocket engines, there remains a lack of in-depth study conducted on their chemical reactions and spray combustion behaviors. To fill this research gap, a simplified chemical kinetic model that is suitable for three-dimensional simulation was proposed in this paper for MMH/N2O4. Then, numerical investigation was conducted using the Volume of Fluid (VOF) model to explore the transient injection and atomization of MMH/N2O4 impinging jets in a small bipropellant thruster. Also, the instantaneous formation and evolution of the fan-shaped liquid film were analyzed. With the spray distribution determined, the proposed kinetic model and two existing mechanisms were applied to simulate spray combustion and heat transfer within the thruster, respectively, under the Euler–Lagrange framework. According to the research results, the liquid film covered nearly the entire chamber wall with a sawtooth pattern, which protected against the high temperatures of the engine wall. Notably, the two existing mechanisms showed significant errors in predicting temperature changes around the wall due to the excessively simplified reaction pathways. In contrast, the proposed model enabled the accurate prediction of the chamber pressure, wall temperature, and thrust with an error of less than 10%. Given the high accuracy achieved by the proposed numerical method, it provides a valuable reference for the development of advanced space engines.

Development of a CFD-DEM Model for a 1 MWth Chemical Looping Gasification Pilot Plant Using Biogenic Residues as Feedstock.

Chemical looping gasification (CLG) is a novel dual fluidized bed gasification process that enables the conversion of solid feedstocks to a nitrogen-free syngas through in situ air separation, avoiding a costly air separation unit. While there have been recent advances in experimental studies, modeling of CLG is almost exclusively restricted to lab-scale units or 1D models. In this study, a 3D CFD-DEM model of a 1 MWth fuel reactor for the conversion of solid biomass was developed. Due to the high computational demand of the DEM method, a coarse-grained approach was used in combination with a simplified reaction network. The hydrodynamics were modeled with an EMMS drag model. Simulations were conducted for two woody biomasses and wheat straw based on experimental data of a 1 MWth CLG reactor. The model was able to predict the pressure profile over the reactor accurately, with a mean error below 10%. Carbon conversion and oxygen carrier oxidation were in good agreement with the experimental data with mean deviations below 5%, while reasonable values below 8 mol % mean error were achieved for the gas composition. Discrepancies in the gas composition as well as temperature profile indicate that further work is needed in the pyrolysis step of the model.

Gasification of mixed plastic-biomass pellets in an updraft fixed bed reactor: A simplified dynamic model

In the context of materials recycling, updraft gasifiers are promising small and middle-scale reactors to obtain building blocks and/or energy from waste plastic and biomasses. To this aim, these kinds of materials can also be mixed and reduced into pellets, while the needed heat enters the process with a heated carrier gas. In order to preliminarily design a gasifier to check its feasibility with an available feedstock, currently available models are inadequate. Thermodynamic ones are useless for the purposes of sizing, while too detailed rate-based models (e.g. based on fluid-dynamic modelling) are too substrate specific, need detailed input data and are extremely time consuming. A dynamic model of a fixed-bed reactor for biomass gasification is presented here. The gasifier is loaded continuously from the top with solid pellets and fed with counter-current air flow. The model considers: i) a one-step gasification kinetics, yielding a product spectrum which matches experimental data from the literature; ii) dynamic gas and solid energy balances and iii) steady-state energy balance for the furnace. The model has been applied to describe a tubular furnace (Ø 40 cm) which gasifies 500–1000 kg day−1 of mixed wastes using air heated up to 1200 °C: on the basis of the produced chemicals, the energy consumption was estimated as ca. 2 MJ per kg of solid feedstock. This simplified approach proved robust in describing the overall yields and start-up dynamics, showing higher reliability than equilibrium models in addressing the temperature profiles, at the cost of a simplified reaction kinetic and pellet description with respect to more complex simulation models. The model validation was done by comparison between the calculations results and available pilot-plant data. An overall good fit of the data can be concluded. The solid-gas heat transfer and the bed packing are the main computational criticalities to achieve a reliable process description.

1,2,3-Triazole-Guided Multi-Component Sonogashira Coupling of Substituted Benzosuberenes Derived from Cedrus deodara Oil

AbstractHerein, Sonogashira coupling at the vinyl bromide position of triazole-bearing benzosuberene has been introduced for the synthesis of potentially bioactive 1,2,3-triazole and conjugated enynes containing benzosuberene analogues. The instalment of triazole moiety on the allylic position dictates the Sonogashira coupling at the vinylic position, the absence of which failed to execute the desired reaction. The Cu-catalyzed cycloaddition initially led to the incorporation of 1,2,3-triazole, which subsequently directed the Pd/Cu-catalyzed Sonogashira coupling to deliver new class of benzosuberene analogues in appreciable yields. The regioselective synthesis of 1,2,3-triazole and conjugated enynes containing benzosuberene analogues has been reported under operationally simple and milder reaction conditions.

Magnetic Nanoparticles with On-Site Azide and Alkyne Functionalized Polymer Coating in a Single Step through a Solvothermal Process.

Background/Objectives: Magnetic Fe3O4 nanoparticles (MNPs) are becoming more important every day. We prepared MNPs in a simple one-step reaction by following the solvothermal method, assisted by azide and alkyne functionalized polyethylene glycol (PEG400) polymers, as well as by PEG6000 and the polyol β-cyclodextrin (βCD), which played a crucial role as electrostatic stabilizers, providing polymeric/polyol coatings around the magnetic cores. Methods: The composition, morphology, and magnetic properties of the nanospheres were analyzed using Transmission Electron and Atomic Force Microscopies (TEM, AFM), Nuclear Magnetic Resonance (NMR), X-ray Diffraction Diffractometry (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR), Matrix-Assisted Laser Desorption/Ionization (MALDI) and Vibrating Sample Magnetometry (VSM). Results: The obtained nanoparticles (@Fe3O4-PEGs and @Fe3O4-βCD) showed diameters between 90 and 250 nm, depending on the polymer used and the Fe3O4·6H2O precursor concentration, typically, 0.13 M at 200 °C and 24 h of reaction. MNPs exhibited superparamagnetism with high saturation mass magnetization at room temperature, reaching values of 59.9 emu/g (@Fe3O4-PEG6000), and no ferromagnetism. Likewise, they showed temperature elevation after applying an alternating magnetic field (AMF), obtaining Specific Absorption Rate (SAR) values of up to 51.87 ± 2.23 W/g for @Fe3O4-PEG6000. Additionally, the formed systems are susceptible to click chemistry, as was demonstrated in the case of the cannabidiol-propargyl derivative (CBD-Pro), which was synthesized and covalently attached to the azide functionalized surface of @Fe3O4-PEG400-N3. Prepared MNPs are highly dispersible in water, PBS, and citrate buffer, remaining in suspension for over 2 weeks, and non-toxic in the T84 human colon cancer cell line, Conclusions: indicating that they are ideal candidates for biomedical applications.

Synthesis and fluorescence properties of europium complex functionalized fiberglass paper.

The development of novel rare earth fluorescent materials and the exploration of their applications have consistently been focal points of research in the fields of materials science and chemistry. In this work, a novel rare earth composite material with good photo-fluorescence properties and self-supporting has been prepared via a simple ultrasonic solvent reaction method. Initially, the Phen moieties is immobilized onto the surface of a self-supporting fiberglass paper using ICPTES, followed by the coordination of Eu(TTA)3 moieties with Phen moieties through a convenient ultrasonic solvent reaction. The resulting GF-Phen-Eu(TTA)3 has been characterized using FTIR, UV-Vis DRS, fluorescence measurements, and so on. The results indicate that the composite material exhibits strong fluorescent emission and presents a vivid red color under ultraviolet light. Further research has shown that the fluorescence of GF-Phen-Eu(TTA)3 strips demonstrated a pronounced quenching effect in response to some transition metal ions (1 mM). Hence, the rare earth composite materials presented here can be utilized not only for the production of optical materials, but also for the development of fluorescence sensing strips.

Effects of fortified electrolyte drink on cognitive, mood, and nutritional parameters: a randomised, single‐blind, placebo‐controlled study

SummaryElectrolyte drinks contain charged minerals and are easily accessible in the market. It has become popular for the food and beverage industry to add nutrients and/or active ingredients to electrolyte drinks and market them as functional beverages. This study aims to determine the interactive effects of electrolyte drinks added caffeine, glucose, and B‐group vitamins (FED) on cognitive, mood index, and nutritional parameters. A total of 34 university students participated in this randomised, single‐blind, and placebo‐controlled study. Participants in the intervention group consumed 500 mL of FED, while participants in the control group consumed 500 mL of an electrolyte drink (ED). Baseline and post‐intervention data on cognitive performance, mood index, blood glucose, blood pressure, heart rate, and urine specific gravity were measured. Results indicated no significant differences (P > 0.05) in post‐intervention cognitive performance scores for simple reaction time, choice reaction time, verbal paired associates, visual paired associates, and digit symbol matching between the FED and ED groups. Levels of fatigue, confusion, and total mood disturbance (TMD) were significantly reduced (P < 0.05) by 46.50%, 62.75%, and 9.54%, respectively, following FED consumption. Post‐intervention data indicated no differences between the FED and ED groups in blood pressure, heart rate, and urine specific gravity, except for the blood glucose parameter, in which the blood glucose level of the FED group was significantly greater (P < 0.05) than that of the ED group. This study indicates that FED consumed in a realistic dose can reduce fatigue, confusion, and TMD. Further studies with a higher caffeine dosage, but within the safe range, could be conducted to investigate the cognitive enhancement potential of FED.

N-Alkylation of Dopamine and Its Impact on Surface Coating Properties.

Surface coating with dopamine (DA) has received significant attention over the past decade due to its compatibility with other surface coating techniques and versatility, making it applicable to solid surfaces regardless of substrate and shape. Much effort has been made to elucidate the origin of its surface coating capability, and as a result, many important factors affecting the coating properties have been determined. For example, it has been reported that the length of the carbon chain between catechol and amino groups, the attachment of specific functional groups to the catechol ring and amino group, and the replacement of the amino group with another functional group can affect the surface coating properties of DA. Despite these various attempts, there are still many factors that remain unknown. In this study, we investigate the effect of N-alkylation on DA coating. N-Ethyl-DA, N-propyl-DA, and N-isopropyl-DA are newly synthesized through simple organic reactions, and the coating efficiency of DA derivatives is compared with nucleophilicity and steric bulkiness. As a result, the coating efficiency of N-ethyl-DA and N-propyl-DA is lower than for pristine DA and N-methyl-DA, but it is possible to coat solid surfaces with alkyl-functionalized DA. In contrast, the coating with sterically bulky N-isopropyl-DA is almost unsuccessful.

Electrochemical Hydrogenation of N‐Heterocycles and Related Substrates: A Mini‐Review

ABSTRACTCatalytic hydrogenation refers to the (often) metal‐mediated addition of dihydrogen (H2) equivalents to unsaturated compounds to form new element‐hydrogen bonds. This conceptually simple reaction is ubiquitous in the production of a vast number of essential chemicals. Despite a growing recognition of the importance of sustainability in manufacturing, the use of fossil‐derived hydrogen gas and precious metal catalysts in hydrogenation remains widespread. Electrochemical variants of these processes are an appealing alternative, especially those that can make use of sustainable Brønsted acids, more abundant electrode materials and renewable electricity. In this mini‐review, we give a selective overview of electrochemical hydrogenation methodologies for N‐heterocycles and some related substrates from the specific perspective of the synthetic chemistry made possible by this increasingly popular approach.

Spectral studies of a selenium(IV) vitamin B3 compounds prepared in the form of nanometer using simple chemical reactions to further use as antioxidant in the preparation of drugs

The current study dealt with selenium metal ion complexes with mixed ligands, consisting of nicotinamide (vitamin B3) as the first ligand, and amino acids such as (histidine, tryptophan, and tyrosine) as the second ligand. It was synthesized in (1:1:1) (selenium: vitamin: amino acid) in molar ratio. By using different characterization techniques such as elemental analysis, the conductance, FTIR, XRD, UV-Vis, TG/DTG, 1H-NMR, XRD, SEM, TEM analyses, the chemical structures and the morphological properties of the synthesized complexes were checked and discussed. The nicotinamide was coordinated as monodentate ligand via the nitrogen of pyridine ring but all amino acids as a secondary ligand coordinated as bidentate through oxygen of carboxylic group and nitrogen of amino group. The complexes demonstrate antioxidant activity with potent scavenging property, the synthesized in the form of nanometer give great importance in increasing efficiency of absorption of human cells to selenium giving the highest efficiency of medical product. All complexes in this study were evaluated for their anticancer effect towards HepG2 and A2780 cell lines. From these data the complex (Se/Nia/ Tyr) can be used as antitumor agents. KEY WORDS: Selenium, Amino acids, Vitamin B3, Mixed ligand, Complexes, Antioxidant Bull. Chem. Soc. Ethiop. 2024, 38(6), 1759-1774. DOI: https://dx.doi.org/10.4314/bcse.v38i6.20

Porphyrin-based schiff-base and aminal nitrogen-rich porous organic polymers for capture of SO2 and CO2

Due to its serious hazards to human health and the environment, the deep removal of sulfur dioxide (SO2) has been of great significance. Thus, it is critical to develop high efficient SO2 capture and sequestration materials in gas purification process. Herein, we reported two novel prophyrin-based nitrogen-rich porous organic polymers (POPs), PrPOA-BP and PrPSN-BP, constructed through the simple catalyst-free condensation reaction. Owing to the strong affinity to SO2 from the conjugate-electron macrocycles structure of prophyrin and nitrogen-rich porous networks, also the high porous structure, these two POPs demonstrated excellent SO2 capture and separation performance with the adsorption uptakes up to 18.2 mmol g−1 (273 K, 1 bar), 13.3 mmol g−1 (298 K, 1 bar), 1.68 mmol g−1 (298 K, 0.01 bar). This very competitive performance has far exceeded most of the prior reported nanoporous materials. Meanwhile, the IAST selectivities of SO2/CO2 (10/90, v/v) could reach 107.8 and 72.0 at 273 and 298 K, 1 bar. This study represents a new type prophyrin-based POPs materials and confirms the intrinsic potential for high efficiency SO2 capture and sequestration.

Accuracy of Reaction Time Measurement on Automated Neuropsychological Assessment Metric UltraMobile.

This observational study examined the accuracy of simple reaction time (RT) measurements on various touchscreen tablet devices using the Automated Neuropsychological Assessment Metric (ANAM) UltraMobile test battery. The study investigated the implications of interpreting ANAM UltraMobile with laptop-based normative data by analyzing the magnitude and variability of RT accuracy across devices. RT accuracy on 10 different tablets was assessed using a photodetector and robotic arm to respond to stimuli at predetermined response times. The recorded RT was compared with the true RT obtained from the robotic arm to calculate the RT error. ANAM UltraMobile recorded slower RTs than the laptop version. Additionally, RT error varied considerably among the 10 tablet models, suggesting psychometrically significant implications that could lead to interpretive errors when using laptop-based normative data. Relative to the RT error from the laptop-based version of ANAM, tablet data from ANAM UltraMobile are significantly slower and exhibit large variability between devices. These differences may have clinically significant implications for the comparability of the two versions. The findings suggest that further research with human participants is needed to assess the equivalence of ANAM UltraMobile with its predecessor.

Analytical Method Development and Validation Based on Simple Color Reactions and Microwave Plasma–Atomic Emission Spectrometry (MP-AES) for the Detection of Adulteration in Teff Injera (Ethiopian Flatbread)

Analytical Method Development and Validation Based on Simple Color Reactions and Microwave Plasma–Atomic Emission Spectrometry (MP-AES) for the Detection of Adulteration in Teff Injera (Ethiopian Flatbread)

Optical characteristics, Judd-Ofelt analysis of enhanced luminescence by flux in thermally stable, novel Eu3+- doped BaZr(PO4)2 phosphor for indoor lighting applications

A series of novel single phased Eu3+ doped BaZr(PO4)2 phosphor were synthesized employing simple solid-state reaction route and studied the influence of different chlorides as fluxes (NH4Cl, KCl, LiCl and NaCl) on structural and photoluminescence properties. The structural characterization reveals pure phase formation of the as prepared phosphors with monoclinic crystal structure. The photoluminescence (PL) spectra recorded under 392 nm excitation depicts intense emission at 612 nm. Further, the concentration of Eu3+ ion was well tuned by carefully studying the PL spectra and the optimised amount of Eu3+ ion in BaZr(PO4)2 is found to be 3.0 mol%. The luminescence properties of phosphor with added aforementioned fluxes were also studied in detail. NH4Cl was found to be the best among all the fluxes taken and the photoluminescence intensity of phosphor gets enhanced by 1.43 times of without flux. The Judd-Ofelt theory was employed for determination of spectral parameters from photoluminescent emission spectra. The temperature dependent photoluminescent studies establishes stability of phosphor emission at operating temperatures. The CIE coordinates were evaluated that confirms the pure red emission under n-UV excitation. All the studies indicate the potential of the said phosphor in phosphor converted white light emitting diodes as red emitter and indoor lighting.

Acid-assisted synthesis of core-shell Prussian blue cathode for sodium-ion batteries

In recent years, core–shell structured Prussian Blue Analogues (PBAs) have been considered as highly promising cathode materials for sodium-ion batteries. Reducing production costs and simplifying the preparation method for core–shell PBAs have also become crucial considerations. This paper presents a novel approach for the first time: by acid-treating the as-synthesized solution from a simple coprecipitation reaction, a high-crystallinity, sodium-rich Mn2+-doped iron hexacyanoferrate (Fe/MnHCF) shell material is self-grown on the surface of manganese hexacyanoferrate (MnHCF). This method significantly improves the electrochemical properties of the MnHCF material. The core–shell structured PBA exhibits excellent cycling performance (with a capacity retention of 95.5 % for 400 cycles at 1 A/g) and high rate performance (134.2mAh/g@10 mA/g, 95.2mAh/g@1 A/g). In this article, we explore the growth mechanism of the high-sodium content, high-crystallinity shell structure and introduce a green chelating agent that is better suited for the crystallization of Mn and Fe-type PBA systems. Our study demonstrates that Mn2+ doping enhances the conductivity of the shell material. Meanwhile, the heterojunction structure of MnHCF@Fe/MnHCF conducive to charge separation and migration. This straightforward synthesis strategy offers a novel approach for fabricating high-performance core–shell structured Prussian Blue Analogue materials.

Synthesis and enhanced H2S gas sensing performances of Co-doped NiO@g-C3N4 heterocomposites

Metal doping is an efficient approach to improve H2S gas sensing performances, but the metal-doped NiO is still faced poor recovery capability at low working temperature. Herein, Co-doped NiO@g-C3N4 heterocomposites were constructed firstly via a simple solid phase reaction. Texture characterizations indicate that Co-doped NiO@g-C3N4 heterocomposites with the architecture of hierarchical microspheres show high specific surface areas and rich surface oxygen vacancies. The gas-sensitive measurements exhibit that the response value of the heterocomposites with g-C3N4 content of 30 wt% (Co-NiO@g-C3N4-3) increases to 45 toward 20 ppm H2S gas at 172 °C, which is about 1.8 times of Co-NiO (23), as well as response/recovery times decreased to ca. 100/130 s. Besides, excellent repeatability, stability and selectivity of Co-NiO@g-C3N4-3 sensors are obtained. The improved H2S gas sensing performances of Co-NiO@g-C3N4 heterocomposites is mainly contributed to the formation of nano-heterojunctions, which promotes electron accumulation at nano-heterojunctions near Co-NiO, facilitates O2 molecules adsorption on the material surface and accelerates the resistance change of the sensors, resulting the enhanced gas sensing performances.