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The emission of volatile sulfur compounds (VSCs) could cause environmental pollution, low-grade products and human health risks. Accordingly, it is of great significance to establish some sensitive and convenient analytical methods for their identification and determination. With the advantages of fast response, high sensitivity and simple instrument, chemiluminescence (CL) and cataluminescence (CTL) are promising for the detection of VSCs. So far, CL analysis of VSCs has been widely applied in various fields based on auxiliary CL methods and sulfur chemiluminescence detector (SCD), while CTL detection is prosperous in the construction of gas sensors, including the exploration of sensing materials and detection modes. Herein, this mini review briefly summarized the progresses, difficulties and future developments of CL analysis and CTL sensor in the detection of VSCs. [ABSTRACT FROM AUTHOR]

Material morphology-dependent cataluminescence (CTL) sensing characteristic and application are presented in this work. Hierarchical hollow microspheres CeO2 were synthesized via the hydrothermal reaction of glucose and N, N-dimethyl-formamide (Glu-DMF). SEM, XRD, TEM, HRTEM and BET were used to characterize the prepared CeO2 materials. Compared with CeO2 cubics (CeO2 Cubs), CeO2 hierarchical hollow microspheres (CeO2 HMs) show an enhanced CTL response to carbon disulfide. The response and recovery times of CeO2 HMs-based CTL sensor towards carbon disulfide are about 8 s and 20 s, respectively. CeO2 HMs exhibits a linear CTL response to carbon disulfide in the concentration range of 0.50~10 μg•mL-1 with an excellent sensitivity and selectivity. These results suggest that CeO2 HMs will be a highly promising CTL sensing material for the detection and monitoring carbon disulfide.CeO2 hierarchical hollow microspheres (CeO2 HMs) were synthesized via the hydrothermal reaction of glucose and N, N-dimethyl-formamide (Glu-DMF). Meanwhile, the prepared CeO2 HMs shows commendable CTL response towards carbon disulfide. Due to the excellent analytical performance of designed CeO2 HMs-based sensor for carbon disulfide, it has potential application value in various locations [ABSTRACT FROM AUTHOR]

Harmful and toxic gas sensing techniques are of vital importance for ecological environment. Abundant physical and chemical properties of metal-organic frameworks (MOFs) have been discovered gradually, such as luminescence, catalysis, and electrical conductivity, which make MOFs evolve into a kind of powerful sensing materials. Although many reported MOF-based sensors have been well reviewed, a comprehensive summary focused on the extremely toxic and harmful gas/vapor sensors is missing. In this review, from a different perspective, the major advances and applications of MOF-based sensors towards the very harmful and toxic analytes in the gas or vapor phase are reviewed, and the sensing mechanisms are also highlighted in detail. Finally, the critical challenges and prospects in this field are discussed from a macro point of view. It is expected that this review could offer a guidance of current state-of-art state on MOF-based hazardous gas/vapor sensors, and accelerates the further practical applications. • The main sensing principles of metal-organic frameworks-based gas sensors are summarized. • Applications of metal-organic frameworks in hazardous gas substances sensing are reviewed. • Challenges and future prospects of these metal-organic frameworks-based gas sensors are highlighted. [ABSTRACT FROM AUTHOR]

Abstract: A novel and highly sensitive gas sensor for alcohols (methanol, ethanol, propanol, isopropanol, butanol, and isobutanol) was proposed based on cataluminescence (CTL) on the surface of nano-CdS. Using cetrimonium bromide (CTAB) as template, the nano-sized sensing material CdS was successfully obtained by a simple hydrothermal synthesis process. The luminescence characteristics and the experiment conditions were investigated in detail. Under the optimized conditions, little interference was observed while eleven foreign substances were passing through the sensor. It demonstrated that this gas sensor has high selectivity for alcohols. The calibration curve (y = kx + b) of the relative CTL intensity versus the concentration of methanol was made, with the linear range of 1.2–76.1μgmL−1 and the detection limit of 0.5μgmL−1 (S/N=3). The relative standard deviation (R.S.D.) (n =7) of relative cataluminescence intensity for 58.5μgmL−1 methanol was 4.3%. There was no significant change of the catalytic activity of the sensor for a week, with R.S.D. less than 5% by collecting the CTL intensity every hour. The method can be applied to detect alcohols in the air. The possible mechanism of CTL on the surface of nano-CdS was discussed preliminarily. [Copyright &y& Elsevier]

Cataluminescence- (CTL-) based sensors are among the most attractive and effective tools for gas sensing, owing to their efficient selectivity, high sensitivity, and rapidity. As the sensing materials of CTL-based sensors, metal-based catalysts easily bring about high costs and environmental pollution of heavy metals. More importantly, the long-term stability of metal-based catalysts is usually rather poor. Metal-free catalysts have unique advantages such as environmental friendliness, low costs, and long-term stability, making them promising materials for CTL-based sensors. Herein, we report the fabrication of a CTL sensor based on a metal-free catalyst. F-doped cage-like SiC was synthesized by wet chemical etching. The as-prepared products showed a rapid, stable, highly selective, and sensitive cataluminescent response to H2S. The stability of the sensor was demonstrated to be fairly good for at least 15 days. After CTL tests, Fdoped cage-like SiC retained its original morphology, structure, and chemical composition. In addition, to the best of our knowledge, this is the first report of a metal-free CTL sensor. Metal-free catalysts are environmentally friendly and low in cost and exhibit long-term stability, which could open a new avenue of CTL sensing. [ABSTRACT FROM AUTHOR]

In the present paper, we have successfully synthesized three new morphologies of enclosed hollow tubular, porous penoy-like and rose-like ZnO architectures via a facile hydrothermal route. The SEM, XRD, TEM, HRTEM and N 2 adsorption–desorption measurements were employed to characterize the as-synthesized ZnO materials. Results of HRTEM exhibited that the exposed crystal facet of enclosed hollow tubular was {10 1 ¯ 0}, while that of the penoy-like and rose-like were both {11 2 ¯ 0}. Moreover, a possible growth mechanism of enclosed hollow tubular ZnO was deduced by exploring the products gathered at different reaction stages and the effects of influencing parameters on cataluminescence (CTL) sensing were also researched. Experimental results indicated that the assorted morphological with different exposed crystal facets ZnO materials exhibited distinctly disparate CTL behavior to detect H 2 S gas and the enclosed hollow tubular ZnO showed the highest catalytic capability. In order to scrutinize the analytical characteristics of the CTL sensor based on enclosed hollow tubular ZnO towards H 2 S, further study was carried out under the optimal experimental conditions. What’s more, gas sensing tests revealed that the enclosed hollow tubular ZnO could have the potential applications as advanced gas sensing materials owning to its excellent gas sensing performances. [ABSTRACT FROM AUTHOR]

A novel and facile dielectric barrier discharge (DBD) plasma-based strategy for fast fabrication of g-C 3 N 4 -Mn 3 O 4 composite is developed. The obtained g-C 3 N 4 -Mn 3 O 4 can be used as a superior cataluminescence (CTL) catalyst for H 2 S gas sensing, with excellent selectivity, high sensitivity, rapid and stable response. Sub-ppm level H 2 S is able to be detected based on the proposed sensor, providing a splendid alternative for monitoring H 2 S in various fields. SEM, TEM, XPS, XRD, N 2 adsorption–desorption measurement were employed to characterize the as-synthesized sensing material. The composite possesses smaller particle size and enlarged specific surface area, which might be attributed to the oxidizing non-equilibrium plasma etching. Besides, using Mn 2+ -impregnated g-C 3 N 4 as the only precursor and air as working gas, this synthesis is free of solvent, extra oxidant/reductant or high temperature, offering advantages such as simplicity in construction, convenient operation and fast speed, and it could be easily implemented on a large scale and extended to manufacturing diverse metal oxide-modified composites for different purposes. [ABSTRACT FROM AUTHOR]

A novel gas sensor toward ketones based on cataluminescence generated on the surface of nanosized NaYF 4 :Er was developed. The sensing materials NaYF 4 :Er was synthesized by a simple hydrothermal method and characterized by powder X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectroscopy. The effect of Er 3+ doping concentration and crystallinity of NaYF 4 :Er on the CTL intensity were studied. When the Er 3+ doping concentration reaches 20%, the materials show excellent sensing characteristics for ketones. Under the optimal experimental conditions, as represented by the acetone and butanone, the gas sensor has fast responses (3 s) and relatively low work temperature (250 °C). The linear range of cataluminescence intensity versus concentration were 2.388–143.28 μg mL −1 for acetone and 2.45–49.0 μg mL −1 for butanone, with a detection limit (signal-to-noise ratio is 3) of 1.7 μg mL −1 and 0.7 μg mL −1 , respectively. Foreign 11 substances in common have little interference which indicates the high selectivity of the CTL sensor for ketones. [ABSTRACT FROM AUTHOR]

Cataluminescence (CTL) was regarded as a simple and efficient sensing method and had made great contributions in gas sensing. Herein, a novel CTL sensor based on Ce(IV)-MOF was designed for detection of H 2 S. The sensor shows outstanding selectivity, high sensitivity and excellent stability in CTL towards H 2 S due to the large surface area and excellent stability of Ce(IV)-MOF. A good linear curve (R2 =0.997) between CTL intensity and H 2 S in the range of 1.04–21.0 μg/mL was obtained with the detection limit of 0.035 μg/mL. Besides, the investigation of the CTL mechanism provides more theoretical support for catalytic reaction. This work broadened the application field of MOF and provided a new clue for the development of catalytic materials in CTL. • Cataluminescence gas sensor with outstanding selectivity, high sensitivity and excellent stability towards H 2 S. • The CTL sensor has excellent thermal stability, porous structure, large surface area and high catalytic activity. • The catalytic oxidization and luminescence mechanism of H 2 S on Ce(Ⅳ)-MOF was investigated in detail. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, Y-doped metal-organic framework-5 (MOF-5) was synthesized by a simple solvothermal method and characterized by X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy and nitrogen adsorption–desorption measurements, and firstly used as gas sensor materials based on cataluminescence (CTL). When isobutanol passed through the surface of the material, CTL emission was observed. The luminescence characteristics and optimal parameters were investigated in detail. Under the optimized conditions, the present gas sensor exhibited a linear range of 6.4–80.1mgL−1 toward isobutanol and with a limit of detection of 3.7mgL−1. The designed CTL sensor based on Y-doped MOF-5 shows no or weak sensing performance for foreign common volatile organic compounds. Moreover, compared with pure MOF-5, Y-doped MOF-5 exhibited a better CTL response to isobutanol under the same conditions. This work exploits a new application domain of metal-organic frameworks (MOFs). [Copyright &y& Elsevier]

In the present work, two-dimensional (2D) transition metal dichalcogenides (TMDs) WS 2 nanosheets, which was synthesized through simple ultrasonic-assisted liquid exfoliation, was used for constructing H 2 S CTL gas sensor for the first time. With respect to other H 2 S CTL gas sensors based on metal oxides and metal-free materials, this sensor based on WS 2 nanosheets is outstanding in H 2 S sensing with excellent properties at relative low temperature of 187 ℃. Furthermore, both of the response and recovery time are as fast as 0.2 s with linear range of 0.26–6.38 µg mL−1 (R2 =0.9933) and detection limit of 0.06 µg·mL−1 (S/N = 3). The characterization results showed that as-prepared WS 2 nanosheets had larger surface, richer edges and more sulfur defects by comparing with bulk WS 2 , which are beneficial for catalytic performance improving. Importantly, the possible mechanism is proposed. In detail, some amount of WO 3 were in-situ generated forming WS 2 /WO 3 hybrids, and WO 3 could keep exchange balance with WS 2 during H 2 S sensing attributed to repeatable S-O bonding exchange. This is crucial for the repeatability of the sensor. This work provides a new view for CTL gas sensing mechanism and may open a new avenue of applying TMDs in H 2 S CTL sensors. • Two-dimensional WS 2 nanosheets was applied to build H 2 S CTL sensor for the first time. • With respect to other H 2 S CTL sensors, this sensor not only reduce the sensing temperature as low as 187 ℃, but also overcome the drawback of poisoning of sulfur compounds. • The mechanism study showed WO 3 were in-situ generated and balanced coexist with WS 2 during H 2 S sensing may due to the repeatable O-S binding exchange, which is crucial to sensor repeatability. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, ZnO hierarchical microspheres were synthesized by hydrothermal methods in the sodium dodecyl sulfate-N,N-dimethyl-formamide-thiourea (SDS-DMF-thiourea) system. XRD, SEM, TEM, and N2 adsorption measurements were used to characterize the prepared ZnO materials. Compared with ZnO nanoparticles (ZnO NPs), the as-prepared ZnO hierarchical microspheres (ZnO HMs) exhibit a better cataluminescence (CTL) response to ethanol. The response and recovery time of the home-made ethanol gas sensor with zinc oxide hierarchical microspheres as sensing materials were about 5s and 25s, respectively. The linear dependence of the sensitivity on the ethanol concentration was observed in the range of 4–400ppm with excellent selectivity. These results indicated that ZnO hierarchical microspheres would be a good candidate for fabricating practical cataluminescence ethanol sensor. [Copyright &y& Elsevier]

Abstract: In the present work, In2O3 hierarchical hollow microsphere and flower-like microstructure were achieved controllably by a hydrothermal process in the sodium dodecyl sulfate (SDS)-N,N-dimethyl-formamide (DMF) system. XRD, SEM, HRTEM and N2 adsorption measurements were used to characterize the as-prepared indium oxide materials and the possible mechanism for the microstructures formation was briefly discussed. The cataluminescence gas sensor based on the as-prepared In2O3 was utilized to detect H2S concentrations in flowing air. Comparative gas sensing results revealed that the sensor based on hierarchical hollow microsphere exhibited much higher sensing sensitivity in detecting H2S gas than the sensor based on flower-like microstructure. The present gas sensor had a fast response time of 5s and a recovery time of less than 25s, furthermore, the cataluminescence intensity vs. H2S concentration was linear in range of 2–20μgmL−1 with a detection limit of 0.5μgmL−1. The present highly sensitive, fast-responding, and low-cost In2O3-based gas sensor for H2S would have many practical applications. [Copyright &y& Elsevier]

Abstract: A novel and highly sensitive gas sensor for triethylamine (TEA) was proposed based on its cataluminescence (CTL) from the catalytic oxidation on the surface of nano-sized LaF3–CeO2. The LaF3–CeO2 nanoparticles were successfully prepared by using a calcination method. The luminescence characteristics and the optimal conditions were investigated in detail. Under the optimal conditions, the present gas sensor exhibited a linear range of 0.9–54ppm, with a correlation coefficient (R) of 0.9987 and a limit of detection (S/N=3) of 0.2ppm. The relative standard deviation (R.S.D.) for 36.5ppm triethylamine was 4.3% (n =6). There was no significant change in the catalytic activity of the sensor after 6 days, with a R.S.D. less than 5%. The proposed triethylamine sensor showed the advantages of good sensitivity and high selectivity. [Copyright &y& Elsevier]

Abstract: In this paper, we presented a carbon tetrachloride gas sensor with strong cataluminescence response based on Ag2Se nanomaterial, which was synthesized via the electrodeposition on the surface of Al foil by directly using a non-aqueous dimethyl sulfoxide (DMSO) solution with CH3COOAg and SeCl4. The deposited Ag2Se material was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Then, the prepared Ag2Se material along with the Al foil substrate was employed to design the carbon tetrachloride gas sensor. Under the optimized conditions, the present gas sensor exhibited a broad linear range of 0.9–228μgmL−1, with a limit of detection of 0.3μgmL−1 (S/N=3). The proposed gas sensor showed good characteristics with high selectivity, fast response and long lifetime. [Copyright &y& Elsevier]

Abstract: This work proposed a gas sensor for the determination of tert-butyl mercaptan, one of the highly toxic volatile sulfur compounds, which was based on cataluminescence emission during its catalytic oxidation on the surface of nanosized V2O5. The cataluminescence characteristics and the optimum conditions, including the morphology of sensing material, the wavelength of cataluminescence emission, the oxygen flow rate and working temperature were investigated in detail. Under the optimized conditions, the calibration curve of the relative cataluminescence intensity versus the concentration of tert-butyl mercaptan vapor was made, with the linear range of 5.6–196μgmL−1 and the detection limit of 0.5μgmL−1 (S/N =3). The relative standard deviation (R.S.D.) (n =5) of relative cataluminescence intensity for 84μgmL−1 tert-butyl mercaptan was 3.6%. There is no or weak response to some common substances, such as formic acid, alcohol (methanol, ethanol, propanol, isopropanol, n-butanol, isoamyl alcohol), o-dichlorobenzene, acetonitrile, ethyl acetate, aldehyde (formaldehyde, acetaldehyde and propanal), 1,2-dichloroethane and ammonia. Furthermore, the proposed sensor was successfully used for determining tert-butyl mercaptan in four artificial samples, with a good recovery. The results demonstrated that the proposed gas sensor had a promising capability for the tert-butyl mercaptan in routine monitoring. [Copyright &y& Elsevier]

Abstract: In the present work, a novel and highly sensitive gas sensor for ethanol was demonstrated based on the intensive cataluminescence emission on the surface of YVO4:Eu3+ luminescent nanocrystals. By a hydrothermal synthesis process with surfactant (PEG 4000), the rice-like sensing material (YVO4:Eu3+) was successfully obtained. Considering the cataluminescence spectra and the fluorescence spectra of YVO4:Eu3+ nanocrystals, an energy transfer mechanism from excited intermediates to the YVO4:Eu3+ nanocrystals was proposed. Under the optimized conditions, the present gas sensor exhibited a linear range of 0.2–31.5μgmL−1, with a limit of detection of 0.03μgmL−1 (S/N=3). The proposed gas sensor showed good characteristics with fast response, high sensitivity and good stability. [Copyright &y& Elsevier]

Abstract: A novel and sensitive gas sensor was proposed for the determination of carbon tetrachloride based on its cataluminescence (CTL) by oxidation in the air on the surface of nanosized ZnS. The luminescence characteristics and the optimal conditions were investigated in detail. Under the optimized conditions, the linear range of the CTL intensity versus the concentration of carbon tetrachloride was 0.4–114μgmL−1, with a correlation coefficient (R) of 0.9986 and a limit of detection (S/N=3) of 0.2μgmL−1. The relative standard deviation (R.S.D.) for 5.9μgmL−1 carbon tetrachloride was 2.9% (n =5). There was no or weak response to common foreign substances including methanol, ethanol, benzene, acetone, formaldehyde, acetaldehyde, dichloromethane, xylene, ammonia and trichloromethane. There was no significant change of the catalytic activity of the sensor for 40h over 4 days, with a R.S.D. of less than 5% by collecting the CTL intensity once an hour. The proposed method was simple and sensitive, with a potential of detecting carbon tetrachloride in environment and industry grounds. The possible mechanism was also discussed briefly. [Copyright &y& Elsevier]

Abstract: When carbon disulfide (CS2) was passing through the surface of nanosized-CeO2 (nano-CeO2), strong chemiluminescence (CL) emission was observed. Based on this phenomenon, a novel sensitive gas sensor was demonstrated for the determination of CS2. The luminescence characteristics and optimal parameters, such as the morphology of the CeO2, wavelength, temperature and the flow rate of carrier gas, were investigated in detail. Under the optimal conditions, the CL intensity versus the concentration of CS2 was linear in the range of 0.9–12.6μgmL−1, with a linear correlation coefficient (R) of 0.999 and a limit of detection (S/N=3) of 3.7ngmL−1 for CS2. The relative standard deviation (R.S.D.) for the determination of 3.6μgmL−1 CS2 was 1.2% (n =5). There is no or weak response to foreign substances, such as alcohol (methanol, ethanol, and n-butanol), aldehyde (formaldehyde and acetaldehyde), acetone, ethyl acetate, chloroform, carbon tetrachloride, toluene, chlorobenzene, hexane and hydrogen sulfide. The stability and durability of the sensor were examined by sampling 7.2μgmL−1 CS2 vapor into the sensor everyday for 3h over two weeks, with a long-term R.S.D. of less than 6.0%. Finally, the proposed sensor was applied to the determination of CS2 in artificial air samples. [Copyright &y& Elsevier]

As a catalyst widely used in industry, manganese dioxide (MnO 2) has different crystalline forms and shows excellent performance in catalytic reactions. Therefore, it is of significance to rapidly evaluate the catalytic performance of MnO 2 online. In this paper, a highly efficient evaluation method based on H 2 S cataluminescence (CTL) sensing was proposed for MnO 2 with different crystalline forms. Firstly, α-, β- and δ-MnO 2 were synthesized successfully and performed diacritical CTL behaviours in the catalytic oxidation of H 2 S. Based on these interesting phenomena, the catalytic performance of α-, β- and δ-MnO 2 was efficiently evaluated online through CTL method for the first time. Results showed that β-MnO 2 had the best catalytic oxidation performance, followed by α- and δ-MnO 2 , and the reactive oxygen species of MnO 2 was the most significant influencing factor. Subsequently, β-MnO 2 was selected to design a CTL sensor for H 2 S detection with a wide linear range (2.43–29.1 μg/mL) and a low limit of detection (LOD, S/N = 3, 0.280 μg/mL). This work not only provided a new and feasible method for online evaluation of the catalytic performance of materials, but also designed a CTL sensor for H 2 S determination with high selectivity and sensitivity. [Display omitted] • Cataluminescence was employed to evaluate materials and screen catalysts efficiently. • The correlation between structures and catalytic performances of MnO 2 was firstly investigated using H 2 S as the model gas. • β-MnO 2 was firstly selected to build a H 2 S CTL sensor with high sensitivity and selectivity. [ABSTRACT FROM AUTHOR]