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[Display omitted] • Fe and Na were found to be the most efficient promotors of Rh/CeO 2 catalyst for CO 2 hydrogenation to ethanol. • The optimized catalyst of 2Rh0.5Fe0.5Na/CeO 2 obtains a high ethanol selectivity of 29.8 % with a CO 2 conversion of 13.0 %. • The modification of Fe and Na promote the formation of Rh+ species, enhancing capacities of CO 2 adsorption and dissociation. • The Rh active sites synergized with Fe and Na can stabilize the adsorbed species of m-CO 3 2− and CO 3 H−. • The generation of HCOO*, CH 3 O* and CH 3 CH 2 O* intermediates promotes the ethanol formation. Rh catalyst is investigated as a strong candidate for CO 2 hydrogenation to ethanol, but it is still challenging because of the poor conversion efficiency. Here, by screening the promotors systematically and varying the amounts of components simultaneously, the optimized catalyst of 2Rh0.5Fe0.5Na/CeO 2 was found to highly efficient catalytic CO 2 hydrogenation to ethanol, giving a high ethanol selectivity of 29.8 % with a superior CO 2 conversion of 13.0 % at 250 °C, 3 MPa, and the ethanol productivity reached 116.7 mmol·g Rh −1·h−1. Characterization results revealed that the modification of Fe and Na, can promote the dispersion of Rh and the formation of Rh+ species, enhancing the capacities of CO 2 adsorption and dissociation. In situ DRIFT experiment illuminated that the Rh active sites synergized with Fe and Na can stabilize the adsorbed species of m-CO 3 2− and CO 3 H−, and promote the generation of HCOO* and CO* intermediates, which can be provided to couple with the CH x species, resulting in the high efficacy for ethanol synthesis from CO 2 hydrogenation. [ABSTRACT FROM AUTHOR]

A series of ZnO/ZrO2 catalysts were synthesized by the precipitation method. The effect of different precipitation modes on the physicochemical properties of the ZnO/ZrO2 catalysts for CO2 hydrogenation to methanol was investigated. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, transmission electron microscopy (TEM), temperature programmed desorption of CO2 (CO2-TPD), temperature programmed reduction of H2 (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that the catalyst of ZnO/ZrO2 prepared by the concurrent precipitation method had more CO2 adsorption sites, resulting in its higher CO2 conversion. While the stepwise precipitation mode increased the surface oxygen content of ZnO/ZrO2, which enhanced the methanol selectivity. Overall, the ZnO/ZrO2 prepared by the concurrent precipitation mode exhibited a highly competitive efficacy for CO2 hydrogenation, giving a methanol selectivity of 81.4% with a CO2 conversion of 5.1% at 280 ℃ and 3 MPa, and the methanol yield reached 4.2%. The effect of different precipitation modes on the physicochemical properties of the ZnO/ZrO2 catalysts for CO2 hydrogenation to methanol was investigated, and the ZnO/ZrO2 prepared by the concurrent precipitation mode exhibited a highly competitive efficacy for CO2 hydrogenation. [ABSTRACT FROM AUTHOR]

A series of Mn3Co16Ox composite oxides catalysts were fabricated via a solid-phase synthesis using different manganese precursors (namely manganese acetate (A), nitrate (N), and sulfate (S)). It has been demonstrated that the obtained catalysts presented variable catalytic activities for CO oxidation and remarkable diversity of physicochemical properties closely depending on the manganese precursors. In detail, the catalytic activity and catalytic durability for CO oxidation under humid conditions generally followed a descending order of Mn3Co16Ox-A > Mn3Co16Ox-N > Mn3Co16Ox-S. The optimum catalytic performance of Mn3Co16Ox-A was predominantly attributed to its larger specific surface area, significantly higher low-temperature reducibility and lattice oxygen mobility, and more plentiful oxygen vacancies. [ABSTRACT FROM AUTHOR]

A series of Cu-ZnO-ZrO2 (CCZ) catalysts were prepared by the solvothermal method with different solvothermal times (1 h, 3 h, 6 h, and 12 h). The physicochemical properties of these catalysts and the catalytic performance for CO2 hydrogenation to methanol were studied. The highest methanol yield was achieved when the solvothermal time was 6 h (CCZ-6). Furthermore, we found that the copper surface area (SCu) increases and then decreases with an increase in the solvothermal time and that there is a strong correlation between the methanol yield and the SCu. This research highlights the crucial influence of the solvothermal time on the structure and catalytic behavior of Cu-ZnO-ZrO2 catalysts, providing a valuable reference for the development of efficient catalysts. [ABSTRACT FROM AUTHOR]

Maintaining high conversion under the premise of high oxygenates selectivity in syngas conversion is important but a formidable challenge in Rh catalysis. Monometallic Rh catalysts provide poor oxygenate conversion efficiency, and efforts have been focused on constructing adjacent polymetallic sites; however, the one‐pass yields of C2+ oxygenates over the reported Rh‐based catalysts were mostly <20 %. In this study, we constructed a monometallic Rh catalyst encapsulated in UiO‐67 (Rh/UiO‐67) with enhanced proximity to dual‐site Rh1,2‐Rhn ensembles. Unexpectedly, this catalyst exhibited high efficacy for oxygenate synthesis from syngas, giving a high oxygenate selectivity of 72.0 % with a remarkable CO conversion of 50.4 %, and the one‐pass yield of C2+ oxygenates exceeded 25 %. The state‐of‐the‐art characterizations further revealed the spontaneous formation of an ensemble of Rh single atoms/dimers (Rh1,2) in the proximity of ultrasmall Rh clusters (Rhn) confined within the nanocavity of UiO‐67, providing adjacent Rh+‐Rh0 dual sites dynamically during the reaction that promote the relay of the undissociated CHO species to the CHx species. Thus, our results open a new route for designing highly efficient Rh catalysts for the conversion of syngas to oxygenates by precisely tuning the ensemble and proximity of the dual active sites in a confined space. [ABSTRACT FROM AUTHOR]

[Display omitted] • Poisoning effects of different K-salts on Mn-HPW are investigated and compared. • De-NO x activities on KN/Mn-HPW and KS/Mn-HPW are inhibited only at <210 °C. • The deactivation can be observed on KC/Mn-HPW at 90–300 °C. • K species decreases the quantity and reactivity of active intermediates. • Cl− aggravates deactivation due to the inhibitory effect on active intermediates. The inevitable presence of various K species in real flue gas may deactivate catalysts used for NH 3 -SCR of NO x. Herein, the poisoning effects of several K salts (KNO 3 , K 2 SO 4 , KCl) on catalytic performance of phosphotungstic acid-modified MnO x (Mn-HPW) were studied. The extent of deactivation follows the sequence of KC/Mn-HPW > KN/Mn-HPW ≈ KS/Mn-HPW. Especially, KCl decreases significantly SCR activity of Mn-HPW at 90–300 °C, whereas K 2 O or K 2 SO 4 exerts the negative effect only below 210 °C. The characterization results show that the presence of K species leads to worse reducibility as well as fewer amounts of Mn4+, Mn3+, and chemisorbed oxygen of the Mn-HPW catalyst. The decrease in the quantity and reactivity of active NH 3 -Lewis and active bridged nitrate is another critical reason for inhibiting NO x elimination at low temperatures on poisoned catalysts. Especially, SO 4 2− in KS/Mn-HPW acts as the spectators in the reaction between active NH 3 -Lewis with NO x or between active bridged nitrate with NH 3 , so de-NO x activity of KS/Mn-HPW is comparable to that of KN/Mn-HPW. For KCl/Mn-HPW, the reducibility and relative concentrations of active sites as well as chemisorbed oxygen are the worst. Furthermore, Cl− further restrains the adsorption of active NH 3 -Lewis, undermining the NO x removal by E-R route; Cl− also hinders the formation of active bridged nitrate, cutting off the reaction through the L-H route. Therefore, KCl exerts the most serious deactivation of Mn-HPW. [ABSTRACT FROM AUTHOR]

A series of CuO-ZnO–ZrO2 (CZZ) catalysts were synthesized via a solvothermal method. The effects of four saturated monohydric alcohols (methanol, ethanol, n-propanol, and n-butanol) as solvents on the physicochemical properties and catalytic performance for the direct synthesis of methanol from CO2 hydrogenation of the prepared catalysts were investigated. N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy mapping, reactive N2O adsorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction by H2 (H2-TPR), and temperature programmed desorption (H2-TPD, CO2-TPD) techniques were used to characterize the catalysts. The results indicate that the catalyst prepared with methanol as solvent (CZZ-M) has the smallest Cu crystallites and the largest metallic Cu surface area, thus exhibiting the highest methanol yield of 7.4% at 240 °C, 3.0 MPa, H2:CO2 of 3 (v/v), and GHSV of 2400 mL/(gcat·h). [ABSTRACT FROM AUTHOR]

[Display omitted] • Zn exerts an unusual promotion effect on SCR performance over Mn-HPW at > 180 °C. • Introducing HPW protects effectively acid sites on Mn from Zn poisoning. • Moderate decrease in redox performance of Zn/Mn-HPW alleviates NH 3 over-oxidation. • Both E-R and L-H mechanisms are applicative to Zn/Mn and Zn/Mn-HPW at 120 °C. • Only E-R route is involved in the reaction for Zn/Mn and Zn/Mn-HPW at 210 °C. MnO x -based catalysts are highly efficient for selective catalytic reduction (SCR) of NO x with NH 3 at low temperatures, but Zn contained in industrial flue gas may poison conventional SCR catalysts, and MnO x -based catalysts usually have low Zn tolerance. Herein, phosphotungstic acid-modified MnO x (denoted as Mn-HPW) was prepared to study the Zn tolerance. It was found that the deposition of Zn on Mn-HPW decreases the SCR activity at < 180 °C, but both NO x conversion and N 2 selectivity are enhanced at 180–300 °C, and > 95% NO x conversion can be achieved on Zn/Mn-HPW. Relevant catalysts were characterized and the results reveal that the decline in the activity at < 180 °C is related to the decrease in the quantities of Mn4+, Mn3+, and chemisorbed oxygen as well as the decreased capacities for adsorbing and activating NH 3 and NO x. The unusual improvement of SCR performance on Zn/Mn-HPW at 180–300 °C is mainly attributed to two aspects: (i) HPW can protect effectively the surface acid sites from Zn poisoning; (ii) The decrease in oxidation properties alleviates the over-oxidation of NH 3 , promoting the participation of more NH 3 in SCR. [ABSTRACT FROM AUTHOR]

A series of M 3 Co 16 O x (M = Cr, Ti, Zr, Fe, Mn) oxide catalysts wrapped by polymer nanofilm were developed by the solid-phase method, and the catalytic activities were investigated for low temperature oxidation of carbon monoxide under moisture-rich condition. The catalysts were characterized by HR-TEM, FT-IR, XRD, N 2 adsorption-desorption, H 2 -TPR, CO-TPD and XPS techniques. The results reveal that the M 3 Co 16 O x composite oxides are high-dispersive mesoporous materials coated by polymer nanofilm with an average thickness in the scope of 4–7 nm. The percentages of surface oxygen vacancy and lattice oxygen on the catalysts decrease in the following order: Mn 3 Co 16 O x > Fe 3 Co 16 O x > Zr 3 Co 16 O x > Ti 3 Co 16 O x > Cr 3 Co 16 O x , which is consistent with their catalytic performances. Among all the prepared catalysts, the polymer nanofilm wrapped Mn 3 Co 16 O x nanoparticles possess the highest Co 3+ /Co 2+ ratio (1.56), the highest percentage of surface oxygen vacancy (17.5%) and lattice oxygen (62.2%), resulting in the best catalytic activity, such as, 100% conversion at 55 °C under moisture-rich condition (∼0.6 vol.%). Moreover, the Mn 3 Co 16 O x catalyst also exhibits long-term catalytic stability (>one month) even at a very high water vapor level (3.1 vol.%) and considerably low temperature (85 °C). [ABSTRACT FROM AUTHOR]

A series of CuO-ZnO-MO x (M = Zr, Al, Cr, Ti) catalysts were prepared by co-precipitation method and characterized by ICP-OES, XRD, N 2 adsorption, N 2 O titration, H 2 -TPR, and XPS. The CuO-ZnO-ZrO 2 catalyst exhibits the highest BET surface area and Cu surface area. For all the CuO-ZnO-MO x catalysts, Cu 0 was the predominant copper species detectable on the surface of both reduced and spent samples. As-prepared CuO-ZnO-MO x catalysts were mixed physically with HZSM-5 zeolite to synthesize dimethyl ether (DME) via biomass-derived syngas. The highest CO conversion and DME yield were obtained over a CuO-ZnO-ZrO 2 /HZSM-5 hybrid catalyst. The CO conversion increases with the increase in the Cu surface area, but the relationship between them is not linear. Due to the H 2 -deficient characteristic of biomass-derived syngas, the water-gas shift reaction, by which H 2 can be produced in-situ for the hydrogenation of CO, plays an important role in the direct DME synthesis. [ABSTRACT FROM AUTHOR]

A series of Cu@ZrO 2 -U framework catalysts derived from Cu@UiO-67 precursors with adjustable copper loadings were constructed by the deposition-precipitation method, and the catalytic activities of methanol synthesis via CO 2 hydrogenation were investigated. The optimized 20-Cu@ZrO 2 -U catalyst showed the best catalytic activity. At 3 MPa and 260 °C, the space-time yield of CH 3 OH (STY CH3OH) reached 2.28 mmol CH3OH /(g cat ·h), which was 3.5 times higher than that of 20-Cu/ZrO 2. The catalyst of 20-Cu@ZrO 2 -U also showed good stability during the 100-h time on stream test. The catalysts were further characterized by XRD, N 2 sorption, TEM, XPS, H 2 -TPR, CO 2 /H 2 -TPD and in situ DRIFTS. The characterization results showed that the stable ZrO 2 framework derived from UiO-67 is propitious to the confine of copper nanoparticles and formation of Cu+-ZrO 2 interfacial sites, which should be responsible for the excellent performance of methanol synthesis. Moreover, in situ DRIFTS was used to probe that the methanol synthesis via CO 2 hydrogenation over 20-Cu@ZrO 2 -U follows a HCOO∗-intermediated reaction pathway. [Display omitted] • A novel Cu@ZrO 2 -U framework catalyst was constructed by Cu@UiO-67 precursor strategy. • The optimized catalyst of 20-Cu@ZrO 2 -U was shown to form rich Cu+-ZrO 2 interfaces. • The methanol yield of 20-Cu@ZrO 2 -U was 3.5 times higher than 20-Cu/ZrO 2 catalyst. • The methanol productivity depends on the ratio of Cu+/Cu0 regulated by Cu+-ZrO 2 interface. • The methanol synthesis mechanism of Cu@ZrO 2 -U follows a HCOO∗-intermediate pathway. [ABSTRACT FROM AUTHOR]

The hybrid systems of CuO-ZnO-Al 2 O 3 /HZSM-5 for the one-step synthesis of DME from biomass-derived syngas were prepared by four different combination methods (granule-mixing, powder-mixing, physical coating and dual-bed fixing) and characterized by N 2 adsorption, XRD, N 2 O titration, H 2 -TPR, NH 3 -TPD and TG techniques. The influences of combination method on the physicochemical properties and catalytic performances of hybrid catalyst were investigated, and the relationship among the combination method, the synergistic effect and the WGS reaction was discussed based on the composition features of the biomass-derived syngas (CO 2 -rich and H 2 -deficient). A maximum of CO conversion and DME yield was obtained over the hybrid catalyst prepared by granule-mixing method. There is a synergistic effect, which remarkably promotes the formation of DME, between the methanol synthesis and the methanol dehydration over the hybrid catalysts except for the hybrid system configured using the dual-bed fixing method. The WGS reaction, playing a pivotal role in the direct DME synthesis because of the in-situ produced hydrogen, relates to the combination method closely. An interaction between the two catalyst components arising in the combination process affects the properties of active sites and further the catalytic performances. The deactivation of the hybrid catalyst is ascribed mainly to the increase in the particle size of Cu in CuO-ZnO-Al 2 O 3. [Display omitted] • Combination method affects synergistic effect, WGS reaction and catalytic property. • Synergistic effect was observed in direct DME synthesis from biomass-derived syngas. • Hydrogen produced via WGS reaction plays an important role for direct DME synthesis. • Interaction between CZA and HZSM-5 changes the amount and property of active site. • Deactivation of hybrid catalyst is ascribed to the increase in d Cu in CZA component. [ABSTRACT FROM AUTHOR]

Abstract: Methane catalytic combustion was carried out over a series of Ca doped Ce0.9− x Cu0.1Ca x O δ (0< x ≤0.3) catalysts prepared by the citric acid complexation–combustion method. The catalyst with x =0.05 showed the optimum activity, with T 50 =478°C, 60°C lower than that of Ca undoped catalyst. The Ca doping promoted the formation of oxygen vacancies of the catalyst. With the increase in Ca amount, more carbonate species were formed on the catalyst surfaces. The carbonate species produced on the catalysts after long-term reaction, were proposed to be responsible for the activity loss of the catalysts. [Copyright &y& Elsevier]

The effect of carbon nanotubes on the catalytic properties of Rh-Mn-Li/SiO2 catalysts was investigated for CO hydrogenation. The catalysts were comprehensively characterized by means of X-ray power diffraction, N2 sorption, transmission electron microscope, H2–temperature-programmed reduction, CO–temperature-programmed desorption, temperature-programmed surface reaction, and X-ray photoelectron spectroscopy. The results showed that an appropriate amount of carbon nanotubes can be attached to the surface of the SiO2 sphere and can improve the Rh dispersion. Moderate Rh-Mn interaction can be obtained by doping with the appropriate amount of carbon nanotubes, which promotes the formation of strongly adsorbed CO and facilitates the progress of CO insertion, resulting in the increase in the selectivity of C2+ oxygenate synthesis. [ABSTRACT FROM AUTHOR]

In this study, a series of Cu–Ce 1-x Zr x O 2 (x = 0, 0.2, 0.5, 0.8, 1) catalysts were prepared by an eco-friendly and facile solid-phase grinding method. The effect of different Ce/Zr molar ratios on the performance of Cu–Ce 1-x Zr x O 2 catalysts for CO 2 hydrogenation to methanol was investigated. The results showed that the Cu–Ce 0.5 Zr 0·5 O 2 catalyst had the best catalytic performance, with CO 2 conversion of 15.2 % and methanol yield of 7.5 % at GHSV = 3600 mL/(g cat ·h)); when GHSV was increased to 20,000 mL/(g cat ·h), the space-time yield of methanol reached 270.8 g CH3OH /(kg cat ·h). X-ray diffraction (XRD), scanning electron microscope (SEM), N 2 adsorption-desorption, N 2 O chemisorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction by H 2 (H 2 -TPR), and temperature programmed desorption (H 2 -TPD, CO 2 -TPD) techniques were used to characterize the catalysts, and the higher reactivity of Cu–Ce 0.5 Zr 0·5 O 2 can be attributed to more Cu0 species, defect oxygen and basic sites. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) results revealed that the hydrogenation of CO 2 to methanol occurred through the formate intermediate pathway. This work proposed an eco-friendly and facile method for the preparation of high-performance Cu-based catalysts and the systematic study provided a deep insight for the development of high-performance Cu-based catalysts for methanol synthesis from CO 2 hydrogenation. [ABSTRACT FROM AUTHOR]

UiO-66 and its modified forms (UiO-66-NH2 and UiO-66-OH) were used as supports to prepare Rh–Mn catalysts by using a co-impregnation method, and their catalytic activities were investigated for the direct synthesis of ethanol-based C2+ oxygenates from CO hydrogenation. The catalysts were comprehensively characterized using N2 sorption, XRD, XPS, DRIFT, and TPSR analyses. The structural and textural properties of the catalysts clearly show that Rh and Mn are highly dispersed in the pores of MOFs, but the order of the original structure is partially sacrificed due to the loading of metals and the synergistic effect of Rh, Mn, and Zr would be influenced by various functional groups present in UiO-66. On combining both in situ FT-IR and TPSR analyses, it is confirmed that the higher number of active sites of Rh0 on RM/UiO-66 promotes the CO dissociation ability and hydrogenation rate, which result in its best catalytic activity with the highest yield of C2+ oxygenates, 197.3 g (kg h)−1. [ABSTRACT FROM AUTHOR]

• Activity, selectivity and H 2 O resistance of Mn–Ce/TiO 2 catalyst was improved by Co. • Operation temperature window of Mn–Ce/TiO 2 catalyst was broadened by Co. • The Co–Mn–Ce/TiO 2 with Co/Ti molar ratio of 0.4 exhibits the best performance. • NH 3 -SCR reaction of the (Co)Mn–Ce/TiO 2 catalysts follows L-H and E-R mechanisms. • Detailed structure-performance relationships of investigated catalysts are obtained. The promotional effect of cobalt (Co) modification on MnCeO x /TiO 2 catalyst for selective catalytic reduction of NO with NH 3 (NH 3 -SCR) was investigated extensively in this study. A series of CoMnCeO x /TiO 2 catalysts with different Co contents were prepared by the facile impregnation method and characterized by XRD, N 2 sorption, XPS, H 2 -TPR, NH 3 /NO-TPD, and in situ DRIFT spectroscopy. The results indicate that the modification of MnCeO x /TiO 2 by Co could significantly improve its low-temperature activity and N 2 selectivity, and broaden operation temperature window (>95% NO conversion at 100–225 °C), and that the optimal mole ratio of Co to Ti in the catalyst is 0.4. Furthermore, the introduction of Co to MnCeO x /TiO 2 could obviously enhance H 2 O resistance. The characterization results reveal that the addition of Co to the MnCeO x /TiO 2 catalyst could enhance the dispersion of MnO x and CeO x , and increase the relative ratio of Mn4+ and Ce3+ on the catalyst surface. In addition, the surface area of MnCeO x /TiO 2 is enlarged evidently after doping of Co. From the results of H 2 -TPR, NH 3 /NO-TPD, and NO oxidation, CoMnCeO x /TiO 2 exhibits stronger reducibility, larger adsorption capacity for NH 3 and NO, and higher NO to NO 2 conversion than MnCeO x /TiO 2 , thus obtaining the higher SCR activity, N 2 selectivity, and H 2 O tolerance. In situ DRIFT spectroscopy tests indicate that the NH 3 -SCR reaction on both MnCeO x /TiO 2 and CoMnCeO x /TiO 2 follow simultaneously the Langmuir-Hinshelwood and Eley-Rideal mechanisms. [ABSTRACT FROM AUTHOR]

• Regenerable DAC process using lysine as a sorbent and N-doped 3D graphene as a catalyst. • N-doped 3D graphene using as an absorption/desorption-enhanced bifunctional catalyst. • The chemical mechanism of DAC was postulated and confirmed by FTIR and DFT. Direct air capture (DAC) of CO 2 is vital for combating global climate change, but DAC technologies have a low absorption efficiency due to the low concentration (∼400 ppm) of atmospheric CO 2. A novel DAC technology was developed to solve this issue using lysine (an amino acid) as a sorbent and N-doped 3D graphene as an absorption/desorption-enhanced bifunctional catalyst. Introducing only 500 ppm N-3DG catalyst increased the working time (≥90% CO 2 absorption efficiency) by 233% and its absorption capacity by 197%. The catalyst also significantly accelerated the CO 2 working desorption capacity and rate by ∼280% and ∼338% at 70 °C, enabling regeneration of the sorbent by utilizing low-temperature waste heats. Furthermore, the excellent stability of the system was confirmed by 50 cyclic tests. The chemical mechanism driving catalytic CO 2 capture was postulated and confirmed by density functional theory computations. This study provides a new strategy for developing next-generation DAC technologies. [ABSTRACT FROM AUTHOR]

Abstract: A series of Zr-based metal-organic frameworks (UiO-66) supported CuO-CeO2 catalysts with various total metal loadings and various Cu/Ce ratios were prepared by using a co-impregnation method. The catalytic activities of the catalysts for low temperature oxidation of carbon monoxide were compared with that supported on the ZrO2 and mesostructured cellular foam silica. The results show that the catalysts supported by UiO-66 are expected to give the best catalytic activity, which should be attributed to the special construction of UiO-66. The samples were further characterized by XRD, TEM, N2 adsorption-desorption, H2-TPR, XPS, and in situ DRIFT. And the catalyst with a bimetallic loading of 50 wt% and Cu/Ce ratio of 3:7 (wt/wt) has the highest catalytic activity, which can be attributed to the larger amount of finely dispersed Cu species strongly interacting with CeO2, the highest amounts of oxygen vacancies and Cu+ species on the catalyst surface.Graphical Abstract: [ABSTRACT FROM AUTHOR]

The influence of the presence of CaO in the Cu/ZSM-5 catalyst on the selective catalytic reduction of NO by NH 3 was investigated. A series of samples containing different amounts of Ca loading have been prepared by the incipient wetness impregnation method. The catalysts were characterized using N 2 adsorption/desorption, powder XRD, H 2 -TPR, NH 3 -TPD and XPS techniques. The Ca loading led to a decrease in the ability for reduction of CuO, a loss of the surface acid sites and a decrease in the surface concentration of Cu, which all appear responsible for the deactivation of Ca-impregnated Cu/ZSM-5 catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • An approach to strengthen the boundary role of Pd/CeO 2 catalyst was developed. • Interfacial catalytic activity was investigated by B-TOF and I 0 × B-TOF. • The CO catalytic oxidation mechanism was proposed on the basis of boundary catalysis. Recently, the interface catalysis has caused more and more attentions. Herein, we developed an approach to strengthen the boundary role of Pd/CeO 2 catalyst, resulting in an obvious increase in its catalytic performance for CO oxidatio n with 100% CO conversion at 20 °C. The results show that after the pretreatment in N 2 at 750 °C and reduction in H 2 at 300 °C, the interaction between Pd and CeO 2 was enhanced, and smaller Pd0 particles and longer interface length (I 0) of Pd-CeO 2 were obtained. In the boundary of Pd-CeO 2 , the presence of Pd2+ promotes the formation of oxygen vacancies in CeO 2 , and CO adsorbed on Pd0 reacts with the oxygen species activated by the oxygen vacancy. The Pd0 sites and oxygen vacancies in the boundary play a decisive role in the CO oxidation over Pd/CeO 2 , which is proved by the B-TOF and I 0 × B-TOF. [ABSTRACT FROM AUTHOR]

A liquid-seed assisted synthesis method was developed to prepare nano-sized lamellar SAPO-n zeolite. The aging of liquid-seed results in the dissolution of solid-seed particles and thus adjusts the ability to direct zeolite crystallization. Lamellar SAPO-34 zeolite with thickness of about 50 nm and well-controlled acidity was synthesized and the zeolite yield reaches 80% (SiO 2 /Al 2 O 3 = 0.4, TEA/Al 2 O 3 = 1.6, liquid-seed contents 3.35%). The bifunctional catalyst consisting of the above prepared SAPO-n and ZnCrOx oxide shows a high space-time yield (STY) of light olefins reaching 212 g•kg−1•h−1 in the reaction of direct conversion of syngas to light olefins. [Display omitted] • Pure SAPO-34 zeolite or SAPO-34/SAPO-18 zeolite intergrowth was selectively synthesized in the presence of liquid-seed. • The directing ability of liquid-seed in zeolite crystallization was investigated by aging the liquid-seed for different time. • Very high STY of light olefins can be reached over ZnCrOx/SAPO-n bifunctional catalyst in the direct syngas conversion. [ABSTRACT FROM AUTHOR]

Water-induced deactivation of the oxides catalysts (especially for the Co 3 O 4 -based catalysts) is a challenging problem. For this reason, highly effective, long-term stable, moisture-resistant polymer nanofilm-coated Fe a Co b O x catalysts were synthesized by a solid-phase method mediated with oxalic acid (OA)/ethlyene glycol (EG) for low-temperature CO oxidation. The effects of the Fe, OA and EG amounts and calcination temperature on the physicochemical and catalytic properties of the Fe a Co b O x catalysts were investigated by various characterization techniques. The results demonstrate that the Fe a Co b O x catalysts are structurally mesoporous, and nanostructured Fe a Co b O x and polymer nanofilm coating play major roles on their high catalytic activity and stability. The nanofilm-coated Fe 3 Co 16 O x nanoparticles prepared under an optimized synthetic condition and calcined at 250 °C possesses higher surface area (134 m 2 /g), Co 3+ /Co 2+ ratio (1.89) and oxygen vacancy (20.5%), and thus exhibits the excellent catalytic performance for CO oxidation, such as, T 50 of −114 °C under normal moisture (3–10 ppm) and T 50 of 47 °C under moisture-rich (∼0.6 vol.%) conditions. Remarkably, compared with the published results, its much-improved long-term catalytic stability (>1 month) can be observed even at a very high moisture level (3.1 vol.%) and relatively low temperature (90 °C). The deactivation of the catalyst at lower temperature resulted from accumulated water and carbonates on the catalyst surface can also be substantially minimized, through the water vapor-resistant with the help of gas-permeable polymer nanofilm coating. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of amino acid methyl esters to chiral amino alcohols is an important and fascinating process. The CuZnMgAlO catalyst for the synthesis of chiral amino alcohols was prepared by the fractional co-precipitation method in the 50-100 g scale. The effect of the reduction gas on the catalytic activity, and the effects of the reaction conditions (R-p-m/Cat, temperature, reaction time, H pressure and solvent) on the catalytic hydrogenation of R-phenylglycine methyl ester (marked as R-p-m) were investigated. When R-p-m in the ethanol solvent was hydrogenated at 5 MPa of H and 80 °C for 10 h over this catalyst reduced by H, 87.7% yield of R-phenylglycinol with ~ 100% ee value was obtained, and its reaction activation energy (E) was 36.7 kJ/mol. After repeated usage 16 times, its catalytic activity was hardly varied. Using this catalyst to catalyze the preparation of other amino alcohols, the high yield of product with ~100% ee value was obtained also. Graphical Abstract: [ABSTRACT FROM AUTHOR]

The Sm, Dy doped and Sm/Dy co-doped NaLa(MoO) spherical phosphors were hydrothermally synthesized by the EDTA-2Na mediated method. Under the excitation of 297 nm, the quenching concentration of Sm in NaLa(MoO) host was determined to be 13%, and the concentration quenching mechanism was discussed to be the electric quadrupole-quadrupole interaction. After Sm and Dy ions were co-doped into the NaLa(MoO) host, the energy transfer behaviors resulted from Dy to Sm ions were investigated by the help of the luminescent spectra of the obtained phosphors. By varying co-doping concentrations of Sm/Dy ions, the emission color of NaLa(MoO):Sm/Dy can be tuned from reddish-orange, pink and white to bluish-green. The CIE chromaticity coordinate, the correlated color temperature and the quantum efficiency of NaLa(MoO):1%Sm, 12%Dy were calculated to be (0.356, 0.320), 4353 K and 20%, respectively. Furthermore, in the temperature-dependent analysis, it presented good thermal stability, which can become a promising single-phased white-emitting phosphor for white LEDs devices. Based on these results, the possible energy transfer mechanism between Dy and Sm in NaLa(MoO):Sm/Dy was also proposed. [ABSTRACT FROM AUTHOR]

A serials of copper catalysts supported on TiO 2 modified with different amount of MgO were prepared by an impregnation method and tested for methanol synthesis from CO 2 hydrogenation. The physico-chemical properties of the catalysts were characterized using XRD, N 2 physisorption, N 2 O titration, XPS, H 2 -TPR and CO 2 -TPD techniques. With the increase in amount of MgO, the Cu surface area initially increases and then decreases. The modification of TiO 2 with MgO hinders the interaction between CuO and TiO 2 , resulting in a decline in the reducibility of CuO. Furthermore, the number and strength of the moderate and strong basic sites over the surface of catalyst increase with increasing MgO loading. The catalyst exhibits an optimum catalytic activity as the content of MgO is 1 wt%. The CO 2 conversion is determined by the Cu specific surface area and the interaction between CuO and TiO 2 , and the CH 3 OH selectivity is related to the surface basicity of catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu/ZnO x particles were encapsulated in UiO-66 by deposition–precipitation method. • Both of metal loading and Cu/Zn mole ratio can regulate the Cu-Zn interaction. • The amount of Cu/ZnO x interfaces is related to the methanol synthesis performance. A series of Cu-Zn catalysts encapsulated by Zr-based metal–organic frameworks (UiO-66) with various metal loadings and Cu/Zn mole ratios were prepared by the deposition–precipitation method, and the catalytic activities were investigated by CO 2 hydrogenation to methanol. The results showed that Cu-Zn@UiO-66 catalyst with Cu-Zn loading of 35 wt% and Cu/Zn mole ratio of 2.5 had the best catalytic activity. At 240 °C and 3 MPa, this catalyst gave the excellent catalytic activity with the highest methanol yield of 9.1%, and showed good reaction stability during 100-hour catalytic test. The catalysts were characterized by N 2 -sorption, XRD, TEM, XPS, H 2 -TPR and CO 2 -TPD. Such excellent performance benefits from the ultrasmall nanoparticles (NPs) and abundant Cu/ZnO x interfaces confined in the UiO-66, and the strong interaction between Cu and ZnO promotes the CO 2 conversion and methanol synthesis. [ABSTRACT FROM AUTHOR]

The effect of iron promoter on the catalytic properties of Rh-Mn/UiO-66-drived catalyst was investigated by syngas conversion. The appropriate addition of Fe can enhance the Rh-Fe interaction, resulting in the enhancement of CO dissociation ability and strength of the Rh-CO bond, which should be responsible for the higher CO conversion and selectivity of C 2 + oxygenates. [Display omitted] • Fe-promoted Rh-Mn/UiO-66-drived catalysts were investigated by syngas conversion. • The Rh-Fe interaction can promote the reduction of Rh active sites. • The Rh0-rich state can enhance CO dissociation ability and Rh-CO bond strength. The effect of iron promoter on the catalytic performance of Rh-Mn/UiO-66-drived catalyst was studied by syngas conversion. The catalysts were completely characterized by means of X-ray diffraction (XRD), N 2 sorption, transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), diffuse reflectance infrared Fourier transform spectra (DRIFTS), and temperature-programmed surface reaction (TPSR). When the amount of Fe doping reached 0.3 wt%, the catalyst has the excellent catalytic activity with the highest C 2 + oxygenates yield of 300.1 g/(kg·h). The results indicated that the appropriate addition of iron can enhance the Rh-Fe interaction, which promote the reduction of Rh active sites. The Rh0-rich state would be observed on the catalysts doped by the appropriate amount of Fe, resulting in the enhancement of CO dissociation ability and strength of the Rh-CO bond, which should be responsible for the higher conversion rate and selectivity of C 2 + oxygenates. [ABSTRACT FROM AUTHOR]

Various ionic liquids (ILs) were in situ prepared on coconut shell activated carbon (CSAC) granules. Cycloaddition of CO 2 to epichlorohydrin (ECH) was continuously carried out in a packed-bed reactor without using solvent or cocatalyst. The conversion rates of ECH over the CSAC tethered Bmim/Br, Bmim/BF 4 , Bmim-OH/Br and Bmim-COOH/Br were 63.4%, 74.5%, 83.4% and 85.9% at 140 °C and 1.4 MPa, respectively. The selectivities to epichlorohydrin carbonate (ECHC) were over 98% for the four catalysts. The ECH conversion stabilized at 82% for the CSAC tethered Bmim-COOH/Br after 50 h of continuous performance in the packed bed reactor. [ABSTRACT FROM AUTHOR]

Different gases were employed to pretreat WO 3 /SiO 2 for the metathesis of 1-butene and ethene to propene. Air-pretreated WO 3 /SiO 2 was inactive, whereas N 2 -, N 2 /H 2 -, and H 2 -pretreated WO 3 /SiO 2 exhibited high 1-butene conversion and propene selectivity. Tetragonal WO 3 and partially reduced WO 2.92 were found to be the active phases/species, whereas monoclinic WO 3 was inactive. N 2 /H 2 - and H 2 -pretreated WO 3 /SiO 2 contained both W 6+ and W 5+ species (i.e., nonstoichiometric WO 3− x ). Air- and N 2 -pretreated WO 3 /SiO 2 only contained monoclinic W 6+ species (WO 3 ) before the reaction. However, the used N 2 -pretreated WO 3 /SiO 2 contained both W 6+ and W 5+ species, suggesting that the N 2 pretreatment can facilitate the formation of some W 5+ species during the reaction. This in situ partial reduction can activate the N 2 -pretreated WO 3 /SiO 2 for the metathesis. [ABSTRACT FROM AUTHOR]

Abstract: Co/CuZnO is known as a base metal catalyst active for C2+ oxygenate synthesis. This study probed the interactions of the different components of Co/CuZnO catalysts on CO hydrogenation using Fischer–Tropsch synthesis (250°C, H2/CO=2) and SSITKA. Only combination of all three metal components produced a catalyst with relatively high C2+ oxygenate selectivity, but with much lower activity compared to that for Co/Al2O3. In situ reaction characterizations, albeit at somewhat different conditions than alcohol synthesis, helped explain interaction of the components. SSITKA, under methanation conditions, indicated that the most striking feature for the combination of Co with ZnO and/or Cu was a much decreased amount of reaction intermediates. Ethane hydrogenolysis results suggested that the different components for these catalysts were in close contact and few or no large ensembles (n ⩾12) of Co atoms existed, confirming that ZnO and/or Cu covered/blocked a substantial number of active sites on Co for CO hydrogenation. [Copyright &y& Elsevier]

Abstract: The mixed solvent-thermal method has been developed for the synthesis of YVO4:Eu3+ luminescent materials in the N, N-dimethylformamide (DMF)/ de-ionized water (DIW) solution. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electronic microscope (TEM), UV/vis absorption and photoluminescence spectroscopies. The results demonstrate that we have obtained the uniform YVO4:Eu3+ cobblestone - like microcrystalline phosphors in the mixed solution of DMF and DIW, which are different to the as-obtained YVO4:Eu3+ nanoparticles in pure DIW. And the as - prepared YVO4:Eu3+ microcrystalline particles are composed of numerous nanoparticles. The assembling phenomenon of the nanoparticles is strongly affected by the pH value of the solution and the volume ratio of DMF/DIW. Under UV excitation, the samples can emit the bright red light. While, the photoluminescence (PL) intensities of YVO4:Eu3+ show some difference for samples obtained under the different reaction conditions. This is because that different microstructures of samples result in different combinative abilities between the surface and the adsorbed species so as to produce the different quenching abilities to the emission from Eu3+ ions. [ABSTRACT FROM AUTHOR]

Maintaining high conversion under the premise of high oxygenates selectivity in syngas conversion is important but a formidable challenge in Rh catalysis. Monometallic Rh catalysts provide poor oxygenate conversion efficiency, and efforts have been focused on constructing adjacent polymetallic sites; however, the one-pass yields of C 2+ oxygenates over the reported Rh-based catalysts were mostly <20 %. In this study, we constructed a monometallic Rh catalyst encapsulated in UiO-67 (Rh/UiO-67) with enhanced proximity to dual-site Rh 1,2 -Rh n ensembles. Unexpectedly, this catalyst exhibited high efficacy for oxygenate synthesis from syngas, giving a high oxygenate selectivity of 72.0 % with a remarkable CO conversion of 50.4 %, and the one-pass yield of C 2+ oxygenates exceeded 25 %. The state-of-the-art characterizations further revealed the spontaneous formation of an ensemble of Rh single atoms/dimers (Rh 1,2 ) in the proximity of ultrasmall Rh clusters (Rh n ) confined within the nanocavity of UiO-67, providing adjacent Rh + -Rh 0 dual sites dynamically during the reaction that promote the relay of the undissociated CHO species to the CH x species. Thus, our results open a new route for designing highly efficient Rh catalysts for the conversion of syngas to oxygenates by precisely tuning the ensemble and proximity of the dual active sites in a confined space., (© 2024 Wiley-VCH GmbH.)

The addition of boron (B) as a promoter to the Ag/SiO 2 catalyst for the selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) was investigated. A comparison of the preparation method for incorporation of B found that the addition during the ammonia evaporation deposition-precipitation synthesis of the Ag/SiO 2 catalyst (Ag-B/SiO 2 ) was inferior to incipient wetness impregnation introduction of the Ag/SiO 2 catalyst (B/Ag/SiO 2 ). Moreover, the effects of B contents (0.5-5 wt %) on the physicochemical properties and catalytic performance of the B/Ag/SiO 2 catalysts were investigated by XRF, N 2 -physisorption, XRD, FTIR, TEM, EDX mapping, H 2 -TPR, NH 3 -TPD, XPS, and catalytic testing. The results indicated that both the catalytic activity and stability of the Ag/SiO 2 catalyst were noticeably enhanced after the introduction of B. The B/Ag/SiO 2 catalyst with 1 wt % B showed the best catalytic performance of 100% DMO conversion and 88.3% MG selectivity, which could be attributed to the highest dispersion of the active metal and the smallest Ag particle size stabilized by the strong interaction between silver and boron species., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Nitrogen-doped hollow carbon spheres (NHCSs) are well prepared by using Cu 2 O microspheres as a hard template and 3-aminophenol formaldehyde resin polymer as carbon and nitrogen precursors. The thickness of the carbon shell can be easily controlled in the range of 15-84 nm by simply adjusting the weight ratios of the precursors to Cu 2 O microspheres, and the Cu 2 O templates can also be further reused. Physicochemical characterization demonstrates that the obtained NHCSs possess a well-developed hollow spherical structure, thin carbon shell and high nitrogen doping content. Due to these characteristics, when further utilized as electrodes for supercapacitors, the NHCSs with the carbon shell thickness of 15 nm show a high capacitance of 263.6 F g -1 at 0.5 A g -1 , an outstanding rate performance of 122 F g -1 at 20 A g -1 and an excellent long-term cycling stability with only 9.8% loss after 1000 cycles at 5 A g -1 in 6 M KOH aqueous electrolyte. This finding may push forward the development of carbon materials, exhibiting huge potential for electrochemical energy storage applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Ca/ZrCu/ZSM-5 catalysts containing different Zr contents were prepared by incipient wetness impregnation. The catalysts were tested for the selective catalytic reduction (SCR) of NO x with ammonia and characterized by N 2 -BET, N 2 O titration, XRD, NH 3 -TPD, H 2 -TPR, and XPS techniques. In the temperature range of 100-170 °C, after calcium impregnation, NO x conversion over the Cu/ZSM-5 catalyst decreased by 11.3-24.3%, while that over Zr 0.10 /Cu/ZSM-5 only decreased by 3.8-12.2%. The improvement of the calcium poisoning resistance of the ZrCu/ZSM-5 catalyst is mainly attributed to an increase in the dispersion and the surface concentration of Cu. Moreover, the addition of zirconium promotes the reduction of CuO by decreasing the interaction between CuO and CaO, which also contributes to the improvement of resistance to CaO poisoning. The apparent activation energy and turnover frequency for the SCR reaction over the Ca/Zr x Cu/ZSM-5 catalysts were calculated and discussed., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

DNAzymes have the potential to suppress gene expression through sequence-specific mRNA cleavage and can therefore play an important role in various gene therapies. Hepatitis B virus (HBV) is still one of the most serious liver infections in people around the world and is difficult to treat. We previously designed a 10-23 DNAzyme called DrzBS, which targets HBV S gene expression, but this enzyme depends on exogenous delivery, and so its application has been limited. To overcome this limitation, we have now developed a chitosan-based nanocarrier (chitosan- g -stearic acid, CSO-SA) for intracellular delivery of DrzBS, then compared the inhibition effect of our CSO-SA/DrzBS complex to a common transfection reagent, Lipofectamine™ 2000/DrzBS, on hepatitis B surface antigen expression. The synthesized CSO-SA assembles into micelles in an aqueous solution and exhibits excellent cytoplasmic targeting, and could protect DrzBS from degradation by ribonuclease. CSO-SA/DrzBS showed a higher inhibition rate (IR) than Lipofectamine™ 2000/DrzBS. Moreover, at the same DrzBS concentration (1.2 μmol L -1 ), the maximum IR of CSO-SA/DrzBS micelles was 2.4-fold that of the Lipofectamine™ 2000/DrzBS complex, and held on for 96 hours. Compared with Lipofectamine™ 2000/DrzBS, CSO-SA/DrzBS achieved a higher HBV inhibition effect. This study demonstrates that CSO-SA micelles can serve as a potential vector for DrzBS and that CSO-SA/DrzBS micelles are a promising application for anti-HBV gene therapy., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)