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CuO–CeO2 (Cu–Ce) catalyst with a CuO/CeO2 mass ratio of 1 prepared by a sol–gel method is used in the CO catalytic oxidation reaction in the actual industrial sulfur-containing atmosphere. At a reaction temperature of 200 °C, the catalyst exhibits quite different stability under sulfur-containing and sulfur-free conditions. When 30 ppm SO2 was added to the feed gas, the Cu–Ce catalyst had an initial CO conversion rate of 100%, gradually decreasing after 26 h, and this catalyst completely deactivated at about 50 h. However, the CO conversion rate of the catalyst under sulfur-free conditions could be nearly maintained at 100% within the measured time range (60 h). The results of IR, Raman, and XPS characterizations proved that the accumulation of cerium sulfate on the Cu–Ce catalyst would cover the active sites of the catalyst, eventually leading to the complete deactivation of the catalyst, which provides favorable evidence for the actual industrial anti-sulfur application.

The Fe-Ti-Ox catalysts with the different Fe contents were used for the catalytic hydrolysis of hydrogen cyanide (HCN) in the presence of H2O, which investigated the roles of Fe chemical valence and oxygen species in HCN removal and the production (NH3 and CO). The results implied that more amounts of Fe3+ species over Fe-Ti-Ox could increase the catalytic hydrolysis activity of HCN while Fe2+ species contributed to the formation of NH3 at high temperatures. Furthermore, the abundance of surface oxygen species was in favour of the catalytic performance of HCN.

The improved Ni/SBA-15 catalysts were prepared by thermal inducing method and applied to dry reforming of methane. The promoting effect exerted by thermal activated reconstruction was studied systematically by means of various characterization techniques. TEM results indicated that the thermal inducing process led to the reconstruction of Ni particles to form ultra-fine Ni nanoparticles (2–3 nm) uniformly distributed on SBA-15. The resulting Ni nanoparticles not only improved catalytic activity but also inhibited the formation of carbon deposition during the DRM reaction. The thermal treatment catalyst with tiny particles presented the superior catalytic performance in the DRM reaction, where H2/CO ratio was close to 1 and no deactivation was discovered after continuous reaction at 750 °C for 50 h. Additionally, it was found that the metal-support interaction was strengthened observably after the thermal activated reconstruction. The strong interaction anchored Ni particles to prevent their high temperature sintering, thus forming stable catalytic centers. Therefore, the conversions of both CO2 and CH4 almost stabilized at 90% and 85%, respectively, for the thermal activated reconstruction samples during the long-term catalytic test.

Catalytic desulfurization is favored for its ability to desulfurize low concentrations of SO2 by generating sulfur without the need for flue gas conditioning or additives. Maintaining reaction efficiency at a low temperature would justify the industrial scale use of this method. To that end, in this study, we modified a previously reported highly efficient CuO-ZrSnO4 catalyst and investigated its desulfurization performance. The non-thermal plasma (NTP) method was used to enhance the low-temperature efficiency of the catalyst. The desulfurization rate was significantly improved without generating excess heat or by-products in the low-output mode of post-plasma-catalysis-type (PPC-type) dielectric barrier discharge (DBD). In addition, we studied the physicochemical properties of the catalyst (pore structure, physical structure, morphology, electronic properties, and chemical state) under plasma enhancement conditions. The catalyst loaded with 20 wt% Cu and aged at 40 °C exhibited optimum desulfurization performance. This study provides a theoretical foundation for the analysis of plasma-enhanced catalytic desulfurization under low-temperature conditions.

Fe(OH)3 and Fe2O3 were first prepared by a precipitation method and then sulfated to obtain the SO2−4 -functionalized SO2−4/Fe(OH)3 and SO2−4/Fe2O3 catalysts for the selective catalytic reduction of NOx with NH3 (NH3-SCR); the promoting effect of SO2−4 functionalization on the performance of Fe2O3 catalyst in NH3-SCR was then investigated. The results indicate that the SCR activity of the SO2−4 -functionalized Fe2O3 catalysts is significantly improved in comparison with that of unmodified Fe2O3. In particular, the SO2−4/Fe(OH)3 catalyst exhibits excellent performance in NH3-SCR, with the NOx conversion of over 80% at 250–450°C; besides, it also display high catalytic stability and resistance towards H2O + SO2. A series of characterization results including XRD, Raman spectroscopy, TG analysis, FTIR spectroscopy, H2-TPR, NH3-TPD and in situ DRIFTS reveal that the functionalization with sulfuric acid can inhibit the growth of Fe2O3 grains; moreover, SO2−4 combines with Fe3+ to form the sulfate complex, leading to an increase in the number of surface acid sites and the acid strength, which can inhibit the ammonia over-oxidation on Fe2O3 and enhance the deNOx performance of Fe2O3.

Electroacupuncture (EA) treatment has proved to significantly decrease nociception in inflammatory nociception model by suppressing the phosphorylation of p38 mitogen-activated protein kinase (p38MAPK). However, repeated EA treatment results in gradual attenuation of its analgesic effects, which was defined as “EA tolerance.” Recent studies have shown that let-7b-5p microRNA (miRNA) contributes to the EA tolerance. The present study aimed to explore the function of let-7b-5p in p38MAPK pathway and the development of EA tolerance in the inflammatory nociception. Dual luciferase reporter gene experiments were used in cortical neurons to determine the target gene locus of let-7b-5p. The threshold of nociception was assessed by tail flick latency (TFL) and paw withdrawal threshold (PWT). Western blots were used to measure the expression of mitogen-activated protein kinase phosphatase 1 (MKP-1) and phosphorylation level of p38MAPK after intracerebroventricular (ICV) injections of let-7b-5p agomir, antagomir, and controls. In vitro dual luciferase experiments demonstrated that the MKP-1-3′ untranslated region (UTR) is a target of let-7b-5p. In vivo experiment, rat with repeated EA treatment exhibits gradual decrease in TFL and PWT, which showed formation of EA tolerance. This trend was delayed after IVC injection of let-7b-5p antagomir and facilitated after IVC injection of let-7b-5p agomir. The protein levels of MKP-1 in the EA+let-7b-5p antagomir group were significantly higher than in the EA + let-7b-5p agomir group. However, P-p38MAPK in the EA+let-7b-5p antagomir group was significantly lower than in the EA+let-7b-5p agomir group. By upregulating the p38MAPK pathway through the inactivation of the MKP-1 gene, let-7b-5p contributes to EA tolerance in complete Freund’s adjuvant (CFA)-induced inflammatory nociception rats. Our work revealed the mechanism of EA tolerance and indicated that let-7b-5p could be targeted to improve the long-term effects of EA. Electronic supplementary material The online version of this article (10.1007/s12031-020-01527-6) contains supplementary material, which is available to authorized users.

A 3D flower-like mesoporous Ce doped ZnO composite composed of nanosheets was prepared by a facile, one-step wet chemical method at room temperature. It was found that the moderate Ce doping can improve the light absorption of ZnO. The photocatalytic activities of the samples were studied by the degradation of Rhodamine B (RhB) and phenol under stimulated sunlight. The 1% mole ratio of Ce doped ZnO composites (denoted as CZ1) showed higher photocatalytic performance than other samples, where 85.1% of RhB and 69.6% of phenol can be removed within 125 min and 120 min, respectively. The Ce4+ doped in the lattice of ZnO can act as the electron trapping sites, which effectively improve the electron-hole separation. In addition, it was also found the annealing temperature had effect on the morphology and structure of Ce doped ZnO. The photocatalytic performance can be further enhanced at proper annealing temperature (500 °C) due to the increase of ZnO crystallinity with maintained flower-like structure and the formation of CeO2-ZnO heterojunction at their tight interface promoting the separation of photogenerated electron-hole pairs.

The promoting effects of SO42− on N2 selectivity for selective catalytic oxidation (SCO) of ammonia to nitrogen over RuO2/ZrO2 catalyst were systematically investigated. The catalysts were measured by different characterization methods (BET, XRD, TEM, NH3–TPD and in situ DRIFTS). The results showed that the introduction of SO42− into RuO2/ZrO2 presented obvious effects on the structure, surface acidity and N2 selectivity of RuO2/ZrO2. The introduction of SO42− obviously increased the amount of surface acid sites, which could promote the adsorption of ammonia species and prevent the excessive oxidation of ammonia to NOx, improving the N2 selectivity dramatically. The DRIFTS results confirmed that the SCO of ammonia over RuO2/ZrO2–SO42− followed the in situ selective catalytic reduction of NOx (i-SCR) mechanism, involving NH3 oxidation to NO species and –NH2 reacted with NO to form the main product N2. The presence of SO42− not only increased the surface acid sites of the catalyst, but also inhibited the production of nitrate species, which was beneficial to improve the N2 selectivity.

A series of CeO2-modified TiO2–ZrO2–SO42− catalysts were employed to the selective catalytic reduction (SCR) of NOx by NH3. The obtained results indicated that the interaction between CeO2 and TiO2–ZrO2–SO42− contributed to the increased reducibility and decreased surface acidity with the augment of CeO2. The in situ DRIFTS results suggested that suitable surface acidity and reducibility could be offered by increasing the ceria loadings from 24 to 40 wt%. The amount of adsorbed NH3 species, amide species (–NH2) and activated nitrate was increased with the augment of ceria. Excessive addition of CeO2 (80 wt%) resulted in the lacking of surface acid sites and induced the inert nitrate species generation on the catalysts surface.

Pt-Pd-HMS catalyst had been prepared by a one-pot approach and tested for toluene combustion. Comparing with conventional impregnated Pt-Pd/HMS (Ea = 111.41 kJ/mol, Pt-Pd particle size = 23.4 nm), the Pt-Pd-HMS exhibited lower activation energy (Ea = 80.23 kJ/mol) and smaller Pt-Pd particle size (6.3 nm). Moreover, surface Pt0/Pttotal of the Pt-Pd-HMS (52.8%) was higher than that of the Pt-Pd/HMS (46.8%), and Pt-Pd-HMS obtained an optimal catalytic performance with T90 = 179 °C at a GHSV = 26,000 mL/(g·h). In-situ DRIFTS indicated that simultaneous generation of benzoate species and aliphatic compounds as intermediates occurred on the active sites of Pt-Pd-HMS. In contrast, the intermediates of toluene combustion on the active sites of Pt-Pd/HMS were dominated by benzoates.

CuO-Fe2O3 catalysts categorized by the thermal treatment were systematically investigated for ammonia oxidation to nitrogen. The activity results exhibited that the calcination temperature had a significant contribution to the difference of the catalytic performance. Lower calcination temperature (≤500 °C) resulted in the excellent catalytic activity owing to the formation of large surface area, superior redox behavior and abundant surface oxygen species. On the contrary, the catalytic activity of catalysts declined with further raising the calcination temperature (≥600 °C) due to the destroyed structure and acid sites. In addition to this, DRIFTS study revealed that the reaction of ammonia oxidation largely depended on the presence of surface active oxygen on the catalysts. In particular, fast ammonia activation was observed on CuO-Fe2O3–500 °C, which was reflected by the rapid formation of –NH2 and nitrate species on DRIFTS combining the XPS results. The intermediates –NH2 and NO of internal selective catalytic reduction (iSCR) predominantly accounted for the excellent catalytic activities.

The effect of Ce or La on the hydrothermal stability of Cu-SAPO-34 catalyst was evaluated by the selective catalytic reduction of NOx by ammonia (NH3-SCR) reaction after hydrothermal aging at 700 °C in 10 vol% H2O/air for 10 h. The hydrothermal stability of Cu-SAPO-34 was dramatically enhanced by introducing small amount Ce or La into Cu-SAPO-34. More than 93% NOx conversion was maintained over the aged Ce or La modified Cu-SAPO-34 at 175–350 °C, while extremely poor NH3-SCR activity was obtained over the aged Cu-SAPO-34. In situ diffuse reflection infrared Fourier transform spectrum (DRIFTS) results illustrated that the hydrothermal treatment cut off the intrinsic “E-R” reaction route over the Cu-SAPO-34 and opened the new reaction pathway (“L-H” mechanism) over the La modified Cu-SAPO-34 catalyst. Additionally, the introduction of Ce or La effectively mitigated the dealumination progress and restrained the aggregation of copper species over Cu-SAPO-34 during the hydrothermal aging, further maintaining the relatively large specific surface area and uniform pore size distribution. Meanwhile, the incorporation of Ce or La enhanced the redox property and stabilized the surface acid sites of Cu-SAPO-34, further facilitating the adsorption and activation of reactants.

A series of different manganese oxides supported Pd catalysts with low Pd loading of 0.3 wt.% have been synthesized and applied to CO catalytic oxidation at low-temperature. In situ DRIFTS was employed to dynamically trace CO oxidation process. It was found that the CO catalytic activity decreased in the order of Pd/OMS-2 > Pd/MnO2 > Pd/Mn2O3 >> Pd/Mn3O4. More interestingly, the Pd/OMS-2 catalyst exhibited exceptionally high activity of T99 = 16 °C, as well as higher reducibility. Furthermore, XPS and in situ DRIFTS results indicated that a substantial of lattice oxygen participated in CO oxidation, contributing to the optimal activity over Pd/OMS-2. While the low reactivity over Pd/Mn3O4 was ascribed to a small amount of lattice oxygen and the strongly adsorbed CO on Pd0.

In the previous research, we found that thermal treatment at high temperature could induce the re-dispersion of Ni particles on SBA-15 for dry reforming of methane (DRM). Here, we aimed to study the re-dispersion behavior of Ni particles of Ni/SBA-15 at different temperatures. The results indicated that the mean Ni particle size of Ni/SBA-15 catalysts were 16.9 nm, 14.5 nm, 7.1 nm and 18.4 nm after thermal treatment at 700 °C, 800 °C, 900 °C and 1000 °C, respectively. It could be seen the optimal inducing temperature of Ni/SBA-15 was at 900 °C. The relatively lower inducing temperature did not drive the re-dispersion of Ni particles sufficiently, while the large Ni particles were formed by re-aggregation of re-dispersive Ni species at relatively higher inducing temperature. After 34 h DRM reaction, encapsulated carbon was formed over the catalyst induced by low temperature and the catalytic performance decreased. However, a slight amorphous carbon was discovered over the catalyst induced at 900 °C with highly dispersion. Interestingly, in spite of a large amount of carbon deposition, the 1000Ni/SBA-15 still maintained excellent catalytic activity.

A series of RuO2-Fe2O3 catalysts varied in RuO2 loading were prepared by sol-gel method and used for selective catalytic oxidation of ammonia to nitrogen. The results indicated that all the RuO2-Fe2O3 catalysts showed an excellent low-temperature catalytic activity and the RuO2 loading played a key role in catalytic activity of ammonia oxidation. Moreover, the characterizations of BET, XRD, H2-TPR and DRIFTS were employed to investigate the relation between the physicochemical property of catalysts and catalytic activity. The research results elucidated that the introduction of RuO2 increased the surface area. The synergistic effect between RuO2 and Fe2O3 enhanced the redox property and the catalytic activity of ammonia oxidation. Meanwhile, the RuO2 loading gave the significant effect on surface acidity of catalysts. Lewis acid sites were predominant on the catalyst surface.

Recent progress of stir bar sorptive extraction (SBSE) in the past six years is reviewed. The preparation methods including electrodeposition, self-assembly, solvent exchange, physical magnetic adsorption and electrostatic spinning, for the coated stir bar are summarized and compared, specifically for a specific material for coatings fabrication, e.g., carbon-based materials and metal organic frameworks. The emerging materials (e.g., graphene, graphene oxide, carbon nanotubes, monolith, metal-organic frameworks and porous organic polymers) applied for coated stir bar fabrication are one of the focus of this review, along with their respective advantages in extraction process and application in trace analysis. The development and application of extraction apparatus of SBSE are also involved. Based on these information, the development status and prospects of SBSE as an efficient sample pretreatment technique in real sample analysis are discussed.

Accumulated evidence has shown that the photosensitizer Verteporfin (VP) may be an ideal agent for various cancer types. However, the effect and mechanism of VP on human cervical carcinoma remain rudimentary. The aim of this study was to investigate the effect of VP on human cervical carcinoma cells (HeLa and SiHa cells) and to elucidate the possible mechanism. CCK-8, wound healing assay, flow cytometry analysis, western blotting, TUNEL staining were performed to evaluate the effects of VP on HeLa and SiHa cells in vitro as well as in vivo on a xenograft model. In addition, the role of endoplasmic reticulum (ER) stress in VP-induced apoptosis was investigated using RT-qPCR and western blotting. The results showed that the viability of HeLa and SiHa cells was suppressed by VP in dose- and time-dependent manners. Compared with the control group, apoptosis rates were higher with stronger TUNEL fluorescence signals in the experimental group, which substantiated that VP induced apoptosis at both 2D and 3D cell levels. Besides, VP can squelch the growth of tumors in both sizes and weights on the xenograft models without impairing ovarian reserve. Mechanism studies demonstrated that VP activated ER stress by upregulating the expression of GRP78, CHOP, and Caspase-12, and VP-induced apoptosis can be alleviated when ER stress pathway was inhibited. Our results provided a foundation for repurposing VP as a promising agent for cervical cancer patients without obvious reproductive toxicity by targeting ER stress pathway, and more researches are required to support its application in clinical practice.

The effect of different pH values (8, 9, 10 and 11) on the catalytic activity over CeSiW catalysts was investigated for the selective catalytic reduction of NO by NH3. CeSiW-9 showed a remarkable higher NOx conversion. The strongest interaction was observed between silicotungstic acid and CeO2 over CeSiW-9, resulting in the improvement of redox ability and surface acidity, which could increase the catalytic activity. The superior catalytic performance of the CeSiW-9 catalyst was attributed to the favored pore structures, excellent redox ability and the abundance of surface acid sites, which depended on pH values in the preparation process of CeSiW catalysts.

MSnO4 (M = Mn, Zn, Co, Mg, etc.) has been widely investigated as an anode material for lithium-ion batteries in recent years, but its practical applications are limited by serious capacity loss caused by severe volume expansion during Li+ insertion/extraction. So far, hollow structures, carbon coating, and encapsulation by reduced graphene oxide have been introduced to improve the electrochemical properties of MSnO4. In this study, Mn2SnO4 nanoparticles@reduced graphene oxide (Mn2SnO4@rGO) composites were prepared using simple steps and applied as anode materials for lithium-ion batteries. The rGO sheet encapsulated Mn2SnO4 nanoparticles show improved electrochemical properties. The first discharge capacity of Mn2SnO4@rGO reaches 1223.5 mAh g-1 and remains at 542.0 mAh g-1 after 100 cycles at a current density of 0.1 A g-1. The electrochemical properties were significantly improved compared to those of pure Mn2SnO4 nanoparticles.

A series of CeO2 prepared with H2SO4 (C–S), H3PO4 (C–P) and H2SO4 + H3PO4 (C–P–S) were investigated in selective catalytic reduction of NOx with NH3. The sulfates contributed to the improvement of Bronsted (B) acid sites, while phosphates were prone to the enhancement of Lewis (L) acid sites, which could improve the catalytic activity. Furthermore, sulfates existed in the surface of C–P–S and C–S; phosphates occurred on the subsurface region or were highly dispersed on the surface of C–P–S and C–P. Besides, the nitrates adsorbed on the CeO2 and NH3 contacted with the sulfates, which followed the L–H mechanism at 200 °C on C–P–S and C–S. The adsorption and activation of NO and NH3 over C–P occurred at the same active sites, which obeyed the E–R mechanism at 200 °C. C–P–S possessed the best catalytic activity because of the appropriate surface acidity and redox property, and more than 80% conversion of NOx was obtained at 220–450 °C. CeO2 modified by H2SO4 (C–S), H3PO4 (C–P) and H2SO4 + H3PO4 (C–P–S) was prepared and used for selective catalytic reduction of NOx by NH3. The presence of sulfate species over C–S and C–P–S contributed to the formation of surface acidity. CeO2 modified by phosphoric acid favored excellent oxidation ability.

A series of silicotungstic acid modified CeO2 (SC-x, x represents the pH value of solution that is used for the preparation of catalysts) were prepared for the selective catalytic reduction (SCR) of NOx with NH3. SC-9 showed the best catalytic activity among the samples. The monodentate nitrate, bidentate nitrate, bridging nitrate and NO2 were detected over SC-9 and SC-10. Monodentate nitrate and bridging nitrate disappeared over SC-8. Furthermore, the monodentate nitrate and bridging nitrate could react with NH4+ on Bronsted acid sites to generate NH4NO3, and then was reduced by NO to form NO2, accompanied with the fast reaction between NO2 and coordinated NH3 on Lewis acid sites in the presence of gaseous NO. Besides, the SCR reaction pathway of SC catalysts followed by the Langmuir–Hinshelwood mechanism and the Eley–Rideal mechanism.

Mesoporous Al2O3-supported Pt-Pd catalyst was prepared via a one-step evaporation-induced self-assembly (EISA) process and employed for toluene combustion. It was found that the T90 (160 °C) and activation energy (43 kJ/mol) of the one-pot prepared Pt-Pd-Al2O3 catalyst are lower than the conventional Al2O3- supported Pt-Pd catalyst prepared by the wet impregnation method (250 °C, 49.8 kJ/mol). Moreover, the one-pot prepared Pt-Pd-Al2O3 catalyst shows the presence of nano Pt-Pd particles in the mesochannels. In terms of the one-pot EISA approach, the bi-metallic Pt-Pd-Al2O3 catalyst exhibits reduced noble-metal mean particle size (6.1 nm) and T90 than the mono-metallic Pt-Al2O3 and Pd-Al2O3 catalysts. It was demonstrated that the present Pt-Pd-Al2O3 catalytic system exhibits the lowest T90 and T50 parameter values and apparent activation energy at comparable space velocities and toluene feed composition compared to several best performed catalysts reported in the literature.

Carbon dioxide reforming of methane to syngas was investigated over a series of MgO promoted Ni/CNT catalysts. MgO played a critical role in improving the catalytic performance of Ni/CNT. The results showed that the addition of MgO strengthened the interaction of Ni and interior surface of CNT. Highly dispersed nickel particles with small size (less than 4.5 nm) were also observed in MgO modified CNT. Otherwise, the NiO nanoparticles were facilely reduced over the catalyst prepared with a narrow size of CNT, as shown in H2-TPR. The reaction tests demonstrated that the Ni-based catalyst with an addition of MgO and narrow size of CNT exhibited better catalytic activity. Furthermore, the lifetime of Ni-based catalyst was prolonged effectively after adding MgO, attributed to the stabilization and dispersion of Ni particles and the effective restraint on the gasification of CNT.

The promoting effects of WO3 on RuO2-Fe2O3 catalyst were systematically investigated for the selective catalytic oxidation of ammonia to nitrogen. It was found that the introduction of 5 wt.% WO3 led to a dramatic promoting effect on the high-temperature N2 selectivity of RuO2-Fe2O3 catalyst, giving 100% NH3 conversion at 250 °C and 94% N2 selectivity at a high temperature of 400 °C. In depth analysis using XRD, Raman and H2-TPR revealed that the addition of WO3 into the RuO2-Fe2O3 catalyst could strongly inhibit the crystallinity of Fe2O3 and decrease the reducibility of RuO2-Fe2O3 catalyst, which were related to the strong interaction between WO3 and Fe2O3. Moreover, in situ DRIFTS studies illustrated that the ammonia oxidation over 1RuO2-5WO3-Fe2O3 catalyst followed the iSCR mechanism, involving the oxidation of NH3 into NO species and the reaction of -NH2 with in situ-formed NO to form N2. The introduction of WO3 not only promoted the formation of more acid sites on the catalyst surface but also restrained the formation of nitrate species at high temperature, with few NOx formed, which contributed to the high N2 selectivity.

The solid superacid TiO2-ZrO2-SO42−-supported 20 wt.% CeO2 catalyst (20CeO2/Ti-Zr-S) was synthesized for selective catalytic reduction of NO with NH3 (NH3-SCR). The NH3-SCR performance was significantly enhanced by the construction of strong acid sites on the surface of 20CeO2/Ti-Zr-S and over 96% NO conversion was obtained at 225–425 °C. Meanwhile, the strong interaction between solid superacid and CeO2 resulted in excellent redox property and abundant surface oxygen species. Furthermore, the NH3-SCR reaction over 20CeO2/Ti-Zr-S catalyst mainly followed the Langmuir-Hinshelwood mechanism at low-temperature (250 °C). The M-NO2 (M = Ce, Ti, Zr) nitrate compounds, monodentate and bridging nitrates were the crucial intermediates in Langmuir-Hinshelwood mechanism. In addition, amide (–NH2) species were available at 350 °C over 20CeO2/Ti-Zr-S catalyst, which facilitated the high-temperature NH3-SCR activity via Eley-Rideal pathway.

Ni-CeZrAl catalyst prepared by a facile co-precipitation method was applied for dry reforming of methane (DRM). DRM catalytic performance of Ni-CeZrAl presented the highest methane conversion of 38.1% at 650 °C, and remained stable at 700 °C for 50 h without deactivation. Kinetic investigations further showed the lowest apparent activation energy (34.5 kJ/mol) of DRM reaction and the highest CH4 TOF value (7.62 × 10−2 s−1) at 640 °C over Ni-CeZrAl. The surface properties of these samples were systematically characterized by H2-chemisorption, H2-TPR, XPS, Raman, CO2-TPD and O2-TPD. It can be found that the superior catalytic behaviors of Ni-CeZrAl catalyst were closely associated with its high dispersion of surface Ni0 active phase. More importantly, ample oxygen vacancies and basic sites favored the formation of disordered carbon and effectively protected the Ni active sites. The inferior activity in Ni-CeAl was due to the formation of NiAl2O4 inactive spinel phase. Similarly, weak interaction and fewer active sites resulted in the inferior catalytic performance of Ni-CeZr. Hence, unique surface properties of Ni-CeZrAl with the optimum active site-support interaction were responsible for considerable performance. This work provides a guidance to design high performance Ni-based catalysts for DRM.

A series of Ce/Fe-Zr-SO42- catalysts have been prepared and developed for selective catalytic reduction of NO with ammonia (NH3-SCR). The catalysts were characterized by XRD, H2-TPR, N2 adsorption-desorption, NH3-TPD and DRIFTS. The characterization results demonstrated that the coexistence of cerium and sulfuric acid on Fe-Zr catalyst could contribute to excellent SCR performance. Among all samples, Ce/Fe-Zr-0.3 S catalyst showed the optimal NOX conversion, reaching more than 80% at 250 °C at a GHSV of 60000 h-1. Moreover, the optimum concentration of SO42- to modify Ce/Fe-Zr catalyst was 0.3 mol/L. The low sulfuric acid concentration contributed to improving low-temperature activity, while high concentration leaded to outstanding high-temperature activity. According to H2-TPR and NH3-TPD, the presence of SO42- increased the total amount of acid sites and more stable sulfate species were formed with higher concentration of sulfuric acid. In situ DRIFTS revealed the NH3 molecule was mainly activated at the Lewis acid site and reacted with the adsorbed NOX species (such as bidentate nitrates) to produce N2 and H2O, which conformed to the L-H reaction mechanism.

During the high-temperature hydrothermal aging process, the tolerance of the zeolite structure and the stability of the active Cu2+ ions directly determined the denitration (deNOx) performance of the copper-based zeolite catalysts in automobile exhaust treatment. Herein, we displayed the hydrothermal aging stability of La-free and La-doped Cu/SAPO-34 catalysts at variant temperatures (650, 750 and 850 °C). A series of characterization results signified that the addition of La into SAPO-34 framework by ion exchange method had obvious contribution to hold back the collapse of SAPO-34 structure and transformation of isolated Cu2+ ions. Different from Cu/SAPO-34 catalyst, Cu/La-SAPO-34 catalyst was more prone to maintain its superior catalytic activity after hydrothermal aging at 750 °C, which possessed great application potential. In addition, NH3-TPD and DRIFT spectra shed light on the variation of surface acidity over two kinds of catalysts inducing by hydrothermal treatment. It could be discovered that doping of La provided moderate surface acidity and excellent hydrothermal stability for Cu/SAPO-34 even up to 750 °C, which was in favor of the NH3-SCR reaction.

The use of porous carrier and coating sorbents in stir bar sorptive extraction (SBSE) contributes to the improvement of extraction efficiency and dynamics. Herein, porous nickel foam (NF) with large surface area and magnetic property was used as the carrier of stir bar. NF was added into the mixture of graphene oxide (GO) and reducing agent, and reduced graphene oxide (RGO) coating was obtained on the surface of NF substrate by in situ hydrothermal reduction. The characterization results of Fourier transform infrared spectroscopy, X-ray power-diffraction and scanning electron microscope showed that GO was partially reduced into RGO, and the RGO coating was uniformly loaded on the NF surface. The obtained RGO-NF composite was used as the stir bar coating for the analysis of six benzotriazole (BZTs) UV absorbents. The extraction efficiency was between 48 and 64% for six BZTs. RGO-NF stir bar exhibited faster adsorption/desorption kinetics than commercial polydimethylsiloxane coated stir bar (50 min vs 120/360 min) due to its porous structure and large specific surface area. On this basis, a method of RGO-NF coated stir bar sorptive extraction combined with high performance liquid chromatography (HPLC)-DAD was established for the determination of six BZTs. Under the optimized conditions, the limits of detection were 0.33–0.50 μg/L for six target BZTs, and the linear range was 1–100 μg/L. The proposed method merits good ability to resist matrix and was used to analyze six BZTs in environmental water samples. The recoveries of target BZTs were obtained within 83.0–112% in the spiked East Lake water and 97.0–111% in the spiked Yangtze River water, respectively.

Highly dispersed Ni/SBA-15 catalysts were prepared via template extraction with varying different extraction times (Ni/S-x, x = 0.5, 3.5, 6.5 h) for methane reforming with carbon dioxide. Based on the various characterization results and initial activity evaluation, Ni/S-3.5 h catalyst showed the best catalytic performance. Compared with the catalyst prepared via template calcination (Ni-S), Ni/S-3.5 h catalyst held steady with CH4 and CO2 conversions while those of the Ni-S catalyst respectively decreased by 15 and 11% during the long-term stability test at 700 °C for 50 h. As TEM and TG–DSC results confirmed, Ni particles in spent Ni/S-3.5 h catalyst stayed well-dispersed with size slightly increasing from an initial 3.9–4.1 nm and nearly no carbon deposition was observed. On the contrary, Ni-S catalyst was subjected to sintered metal particles (increased from 11.6 to 18 nm) and formed carbon fibers. The prominent resistance to sintering and coking over stable Ni/S-3.5 h catalyst was attributed to the high dispersion and strengthened metal-support interaction induced via the residual in situ templates.

A series of CuO-Fe 2 O 3 composite oxides were successfully prepared for low temperature selective catalytic oxidation of ammonia (NH 3 -SCO). Higher Cu/Fe ratio in CuO-Fe 2 O 3 catalysts led to higher activity for NH 3 oxidation and the lower Cu/Fe ratio improved the N 2 selectivity. The optimal catalyst with a Cu/Fe molar ratio of 5:5 displayed a low complete conversion temperature ( 2 selectivity (>91%). H 2 -TPR results indicated that the synergistic effect existed between Fe 2 O 3 and CuO, which was beneficial to the catalytic performance. The results of the DRIFTS showed that NH 3 -SCO reaction mainly followed the internal SCR (i-SCR) mechanism. The adsorbed NH 3 was first activated and reacted with atomic oxygen to form the nitrosyl (-HNO). Then the -HNO was oxidized by oxygen atoms from O 2 to form NO species. Meanwhile, the in situ -formed NO could react with -NH 2 to form the main product of N 2 .

Ni/SBA-15 catalyst was prepared by homogeneous precipitation method (Ni-HP) and used for dry reforming of methane (DRM). The related characterization results indicated that the Ni particles were highly dispersed with a size range of 2-5 nm. Compared with Ni/SBA-15 catalyst prepared by impregnation (Ni-IM), the reduction temperature of Ni-HP obtained from H2-TPR was greatly improved, suggesting the stronger metal-support interaction. After reacting at 700 °C for 100 h, the CH4 conversion of DRM over Ni-HP catalyst slightly decreased from 74.5% to 73.8%. While, for the Ni-IM catalyst, the CH4 conversion dropped from 61.7% to 37.3%. Furthermore, the average particle size of Ni-HP was 3.7 nm and 4.7 nm before and after the long-time stability test, respectively, ascribed to the good anti-sintering property. Although a certain amount of coke was produced, mainly with disorder filamentous carbon of base-growth, the Ni/SBA-15 prepared by homogeneous precipitation exhibited excellent catalytic activity and stability.

The CeO 2 -ZrO 2 -WO 3 catalysts were investigated for the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR). The results indicated that monodentate nitrate species generated from amorphous WO 3 , and these species could not be observed over CeO 2 -ZrO 2 -WO 3 with the presence of Ce 2 (WO 4 ) 3 compounds. The formation of amorphous W species resulted in the abundant of Ce 3+ and oxygen vacancies. Besides, the amorphous W species could enhance the surface acidity and NO oxidation ability. Nitrate species (bridging nitrate and monodentate nitrate), coordinated NH 3 and NH 4 + all participated in the NH 3 -SCR process. The NH 3 -SCR reaction pathway of CeO 2 -ZrO 2 -WO 3 mainly followed Langmuir-Hinshelwood mechanism.

A series of precipitants and commercial surfactants (soft templates) were employed to synthesize mesoporous/nano CeO2 by a hydrothermal method. As-prepared CeO2 was impregnated with palladium and employed for low-temperature catalytic oxidation of CO. It was found that both soft templates and precipitants had significant effects on the morphology, particle size, crystallinity, and porous structure of the CeO2, having a significant effect on the surface palladium abundance, molar ratios of surface species, and catalytic activity of the final impregnated Pd/CeO2. Using ammonia as precipitant could facilitate increased surface palladium abundance and surface molar ratios of PdO/Pd SMSI , Ce3+/(Ce3+ + Ce4+), and Osurface/Olattice. The catalytic activity of the final Pd/CeO2 catalysts could be enhanced as well. The optimal P123-assisted ammonia-precipitated Pd/CeO2 catalyst exhibited over 99% catalytic conversion of CO at 50 °C.

A series of Ni/SBA-15 (AM) catalysts were prepared by chelating ligand assisted impregnation method. The results showed that the chelating ligand played a positive promoting role for CH4 dry reforming with CO2 over Ni/SBA-15. The electron-pair donor atoms and the high viscosity of chelating agent could inhibit the aggregation of nickel species and contribute to the well-dispersed Ni particles with size of

Mesoporous silica-supported Ni can serve as alternative effective catalysts for dry reforming of methane. However, conventional synthesis method requires long synthetic time and high cost, and the resulting catalysts show unsatisfactory catalytic stability due to coking and sintering. In this paper, we reported a facile, low-cost and environmental benign method to introduce Ni species into HMS mesoporous silica (Ni-HMS) in a self-assembled way. FT-IR, H 2 -TPR, and TEM manifested that the obtained Ni-HMS established uniform distributed Ni particles (3.9 ± 0.5 nm) and strong metal-support interaction derives from Si-O-Ni bonding. The dry reforming of methane results demonstrated that the Ni-HMS showed more active and stable catalytic performance than that of Ni impregnated HMS catalyst (Ni/HMS). Notably, the catalytic activity was well maintained even after reacting at 700 °C for 100 h. HAADF-STEM and TG-DSC revealed that coking and sintering were unnoticeable over the endurance-tested Ni-HMS catalysts. The strong anchor effect of pore wall to Ni nanoparticles inherent to the one-pot synthesis was suggested to be the original reason for enhanced resistance toward coking and sintering.

The mechanism of phosphotungstic acid modification CeO 2 catalysts (P-W/CeO 2 ) with different CeO 2 supports were investigated by in situ diffuse reflectance infrared transform spectroscopy for the selective catalytic reduction of NO by NH 3 . The results indicated that the NH 3 -SCR reaction over P-W/CeO 2 followed both the Langmuir–Hinshelwood mechanism and the Eley–Rideal mechanism. The reaction between NH 4 + and bidentate nitrate (NO 3 − ) took place, and then the H 2 O, N 2 and adsorbed NO 2 were formed. The coordinated NH 3 species reacted with adsorbed NO 2 and gaseous NO to generate N 2 and H 2 O. The interaction between CeO 2 and phosphotungstic acid contributed to the favored surface acidity (Lewis and Bronsted acid sites) and excellent redox property. The Bronsted acid sites facilitated the generation of NO 2 -adsorbed and Lewis acid sites accelerated the Eley–Rideal mechanism, while the NO oxidation to bidentate nitrate or NO 2 -adsorbed species was an important step in the reaction mechanism of P-W/CeO 2 .

Studies showed that increased let-7b-5p microRNA during repeated electroacupuncture (EA) treatment was associated the formation of EA tolerance, which manifested as gradually decreased nociceptive threshold. Proenkephalin (PENK) is the precursor of enkephalin which is a pivot neuropeptide responsible for the decreased nociceptive threshold in EA. The aim of this study was to evaluate the relationship between let-7b-5p and PENK in EA tolerance.The target gene of let-7b-5p microRNA was determined through the dual-luciferase reporter assay in cortical neurons. Seventy-two Sprague Dawley rats received a combination of EA and intracerebroventricular injection of microRNA (let-7b-5p agomir, antagomir or their controls). The nociceptive thresholds were assessed with radiant heat tail-flick method. PENK and let-7b-5p were measured with Western Blot and qPCR, respectively, after administration of let-7b-5p agomir, antagomir, and their controls at day 1, 4 and 7.Let-7b-5p targeted the 3' untranslated region of Penk1. The nociceptive thresholds in Let-7b-5p agomir + EA group were decreased (p 0.05) compared with those in Let-7b-5p antagomir + EA group at day 1 to 7. Compared with Let-7b-5p agomir + EA group, the expression level of PENK in Let-7b-5p antagomir + EA group was increased at days 1, 4, and 7 (p 0.05) CONCLUSION: Let-7b-5p may be a new potential target for decreasing the EA tolerance effect and facilitating the application of EA in treating chronic nociception of patients.

Background: Electroacupuncture (EA) tolerance, a negative therapeutic effect, is a gradual decline in antinociception because of its repeated or prolonged use. This study aims to explore the role of thymosin beta 4 (Tβ4), having neuro-protection properties, in EA tolerance (EAT). Methods: Rats were treated with EA once daily for eight consecutive days to establish EAT, effect of Tβ4 on the development of EAT was determined through microinjection of Tβ4 antibody and siRNA into the cerebroventricle. The mRNA and protein expression profiles of Tβ4, opioid peptides (enkephalin, dynorphin and endorphin), and anti-opioid peptides (cholecystokinin octapeptide, CCK-8 and orphanin FQ, OFQ), and mu opioid receptor (MOR) and CCK B receptor (CCKBR) in the brain areas (hypothalamus, thalamus, cortex, midbrain and medulla) were characterized after Tβ4 siRNA was administered. Results: Tβ4 levels were increased at day 1, 4, and 8 and negatively correlated with the changes of tail flick latency in all areas. Tβ4 antibody and siRNA postponed EAT. Tβ4 siRNA caused decreased Tβ4 levels in all areas, which resulted in increased enkephalin, dynorphin, endorphin and MOR levels in most measured areas during repeated EA, but unchanged OFQ, CCK-8, and CCKBR levels in most measured areas. Tβ4 levels were negatively correlated with enkephalin, dynorphin, endorphin, or MOR levels in all areas except medulla, while positively correlated with OFQ and CCK-8 levels in some areas. Conclusion: These results confirmed Tβ4 facilitates EAT probably through negatively changing endogenous opioid peptides and their receptors and positively influencing anti-opioid peptides in the central nervous system.

CeO2-based catalysts have raised extensive attention in selective catalytic reduction of NO with NH3 but the poor T90 operation window limits their industrial application. In present work, FeOx-CeO2 mixed oxides were prepared by a sol-gel method for NH3-SCR, and the effects of sulfuric acid treatment on the catalytic performance were systematically investigated. The results showed that sulfuric acid treatment significantly improved the high temperature activity. Compared to the FeOx-CeO2 sample, the T90 operation window of FeOx-CeO2-S was greatly broadened from 200−300 °C to 250−450 °C. Various characterizations demonstrated that sulfuric acid introduction increased redox capacity and also enhanced surface acidity. The synergistic effect of these two parameters was closely associated with the enhanced performance. Further investigations revealed that the sulfuric acid modification favored the formation of active intermediate species for N2 generation, while inhibited the formation of N2O and NOx, thus contributing to the high catalytic activity and N2 selectivity.

Iron-tungsten composite oxide catalysts have been prepared using a no-water grinding method followed by calcination from 400 to 800 °C. Treatment from 400 °C to 800 °C led to the crystallinity increase and weaker interaction between Fe and W. The catalyst calcined at low temperature (400 °C) obtained ample lattice defect, more surface Fe2+ species and surface oxygen and showed the greatest low-temperature catalytic activity. At high calcination temperature, less surface oxygen-vacancies and weak reducibility of samples were found and correspond to decreased catalytic properties. The calcination at 500 °C for iron-tungsten catalyst was accompanied by the coexistence of surface defect and FeWO4 or WO3 species with an optimal ratio, prompting its best active window with more than 90% NOx conversion at 220–500 °C. More specially, the unsaturated cations (Fem+ and Wn+) about surface defect gave rise to form more Lewis acid sites, and the O-W-O and W-O-W in connection with hydrated tungsten species led to the formation of Bronsted acid sites. The reaction intermediate between NO3− and NH2 formed on the surface of FeOx-WO3 catalyst was such a crucial factor in improving the reaction performance of NH3-SCR and the difference of N2 selectivity.

The present research has probed the effect of different thermal-treatment temperatures on the catalytic activity of CO oxidation and the physio-chemical properties of an OMS-2 supported palladium catalyst. The catalytic activity of Pd/OMS-2 increased with an increase in the thermal-treatment temperature from 300 to 500 °C. The optimal Pd/OMS-2 catalyst exhibited over 99% CO conversion at 35 °C. An elevated thermal-treatment temperature up to 500 °C led to a decrease in OMS-2 crystallinity and surface chemisorbed oxygen (–OH), while the surface atomic ratios of oxygen/Mn and palladium increased with the calcination temperature. A high thermal-treatment temperature above 500 °C led to the phase transformation of OMS-2 into Mn2O3, and an abrupt alteration in the Pd–support interaction and deactivation of the Pd/OMS-2 catalyst.

Nickel-containing ordered mesoporous silica materials (Ni-SBA-15, Ni-KIT-6 and Ni-MCM-41) were prepared by solid-state grinding method and applied to the dry reforming of methane (DRM). After reacting at 700 °C for 100 h, the catalytic activity and stability declined in the following sequence: Ni-SBA-15 > Ni-KIT-6 > Ni-MCM-41. The characterization results indicated that the average size of the Ni particles on Ni-SBA-15 was ∼3.2 nm, and no visible NiO diffraction peak observed on Ni-SBA-15, implying that the nickel species were highly dispersed on the SBA-15. Moreover, the reduction temperature of Ni species on Ni-SBA-15 obviously shifted to higher temperature compared with the Ni/SBA-15 prepared by impregnation method, indicating that the interaction between the Ni species and mesoporous support was enhanced. The Ni-SBA-15 also presented excellent resistance to the carbon deposition, and the carbon deposition decreased in the order of Ni-MCM-41 (38.8%) > Ni-KIT-6 (8.1%) > Ni-SBA-15 (6.3%) after reacting at 700 °C for 100 h.

Manganese oxide octahedral molecular sieves (OMS-2) synthesized from hydrothermal (H-OMS-2), reflux (R-OMS-2), co-precipitation (C-OMS-2), and solid phase (S-OMS-2) methods were impregnated with palladium and used for CO catalytic oxidation. Preparation methods presented an obvious effect on the morphology and catalytic activity of Pd/OMS-2 catalysts for CO oxidation. The hydrothermal synthesized OMS-2 (Pd/H-OMS-2) exhibited more ordered nanorod structure and higher crystallinity than Pd/R-OMS-2, Pd/C-OMS-2, and Pd/S-OMS-2. Further surface analysis indicated that different preparation methods of synthesizing OMS-2 and the impregnation process followed have a significant effect on the chemical states of Mn and O over the final Pd/OMS-2 products. The kinetics studies showed the trend of apparent activation energy (E a) over different catalysts: Pd/H-OMS-2 (18.19 kJ/mol)

A series of CeO2 supports over phosphotungstic acid doped CeO2 (P-W/CeO2) prepared by hydrothermal (Cat-A), sol–gel (Cat-B) and precipitation (Cat-C) methods were investigated in selective catalytic reduction of NOx by NH3. The catalytic activity of P-W/CeO2 was dramatically affected by the preparation methods of CeO2 supports. Results implied that the incorporation of W species could cause the decease of cell parameter and lattice contraction, resulting in inducing the formation of more Ce3+ and oxygen vacancies over the Cat-A catalyst, leading to the excellent oxidation ability and SCR activity. Furthermore, the Cat-A catalyst possessed the most amount of Lewis acid sites, resulting in the superior catalytic activity. Besides, the larger specific area and the excellent redox ability were responsible for the outstanding SCR performance. In brief, the favorable activity in NH3 oxidation, as well as NO oxidation, contributed to the excellent catalytic activity. Therefore, the Cat-A catalyst exhibited the best SCR activity and over 90% NOx conversion was obtained at 190–450 °C.

A series of sulfated CeO 2 catalysts were synthesized by impregnation and sol-gel methods and used for selective catalytic reduction (SCR) of NO x by NH 3 . The results showed that the sulfated CeO 2 catalysts prepared by sol-gel method showed excellent catalytic activity at 150–450 °C, and more than 90% NO x conversion was obtained at 232–450 °C with a gas hourly space velocity of 60000 h −1 . The catalysts were characterized by X-ray diffraction (XRD), N 2 adsorption, Raman, thermogravimetry (TG), H 2 -temperature-programmed reduction (H 2 -TPR) and Py-infrared spectroscopy (Py-IR). The excellent SCR performance was associated with the surface acidity and the micro-structure. The introduction of sulfate acid into CeO 2 could increase the amount of Bronsted and Lewis acid sites over the catalysts, resulting in the improvement of the low temperature activity. The sulfated CeO 2 catalysts prepared by sol-gel method possessed lower crystallization degree, excellent redox property and larger specific surface areas, which were responsible for the superior SCR performance.

The Cu/ZSM-5 catalysts prepared by different copper precursors were used for the selective catalytic reduction (SCR) of NO x with NH3. The Cu/ZSM-5 catalyst prepared by the copper nitrate (Cu/ZSM-5-N) presented the best performance among the Cu/ZSM-5 catalysts and showed above 90 % NO x conversion at 225–405 °C. The average particle size of CuO was 5.82, 9.20, and 11.01 nm over Cu/ZSM-5-N, Cu/ZSM-5-S (prepared by copper sulfate), and Cu/ZSM-5-C (prepared by copper chloride), respectively. The Cu/ZSM-5-N catalyst showed the highly dispersed copper species, the strong surface acidity, and the excellent redox ability compared with the Cu/ZSM-5-C and Cu/ZSM-5-S catalysts. The Cu+ and Cu2+ existed in the Cu/ZSM-5 catalysts and the abundant Cu+ over Cu/ZSM-5-N might be responsible for the superior SCR activity.

A series of CeO2–ZrO2–WO3 (CZW) catalysts prepared by a hydrothermal synthesis method showed excellent catalytic activity for selective catalytic reduction (SCR) of NO with NH3 over a wide temperature of 150–550°C. The effect of hydrothermal treatment of CZW catalysts on SCR activity was investigated in the presence of 10% H2O. The fresh catalyst showed above 90% NOx conversion at 201–459°C, which is applicable to diesel exhaust NOx purification (200–440°C). The SCR activity results indicated that hydrothermal aging decreased the SCR activity of CZW at low temperatures (below 300°C), while the activity was notably enhanced at high temperature (above 450°C). The aged CZW catalyst (hydrothermal aging at 700°C for 8 hr) showed almost 80% NOx conversion at 229–550°C, while the V2O5–WO3/TiO2 catalyst presented above 80% NOx conversion at 308–370°C. The effect of structural changes, acidity, and redox properties of CZW on the SCR activity was investigated. The results indicated that the excellent hydrothermal stability of CZW was mainly due to the CeO2–ZrO2 solid solution, amorphous WO3 phase and optimal acidity. In addition, the formation of WO3 clusters increased in size as the hydrothermal aging temperature increased, resulting in the collapse of structure, which could further affect the acidity and redox properties.