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Laser-ablated gold atoms have been codeposited at 4 K with nitric oxide in excess argon and the low temperature reactions of Au with NO in solid argon have been studied using infrared spectroscopy. The reaction products Au2NO-, Au2NO, Au3NO, Au4NO, and Au5NO are formed in the present experiments and characterized on the basis of isotopic shifts, mixed isotope splitting patterns, stepwise annealing, the change in reagent concentration and laser energy, and comparison with theoretical predictions. Density functional theory calculations have been performed on these systems to identify possible reaction products. The agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these molecules based on the matrix infrared spectra. Plausible reaction pathways have been proposed for the formation of these molecules. [ABSTRACT FROM AUTHOR]

It was found that, when a little amount of KH (5 mol%) was added in the LiH–NH3hydrogen storage system, the hydrogen desorption kinetics of this system at 100 °C was drastically improved by the KH “pseudo-catalytic” effect. [ABSTRACT FROM AUTHOR]

To overcome the drawbacks of high solubility and instability of polyoxometalates (POMs) in aqueous solution and to expand their application in the electrocatalytic reduction of CO2 (ECR), we assemble sandwich-type POMs, K10[(PW9O34)2M4(H2O)2] (M = Mn, Ni, Zn, shortened as P2W18M4), into the hexagonal channel of a porphyrin-based metal–organic framework (MOF) PCN-222 to form P2W18M4@PCN-222 composites. Their ECR behavior displays polyoxoanion-dependent activity. P2W18Mn4@PCN-222 demonstrates a faradaic efficiency of 72.6% for the CO product (FECO), more than four times that of PCN-222 (FECO = 18.1%), and exhibits exceptional electrochemical stability over 36 h. P2W18Ni4@PCN-222 and P2W18Zn4@PCN-222 slightly increase (26.9%) and decrease (3.2%) in FECO, respectively. We combine the results with density functional theory (DFT) calculations to help understand the intrinsic reasons which reveals that the rate-determining step (RDS) reaction energy of P2W18Mn4@PCN-222 and P2W18Ni4@PCN-222 is significantly reduced compared to that of PCN-222. It is different in P2W18Zn4@PCN-222. Frontier molecular orbitals electron distribution results hint at directional electron transfer from P2W18Mn4/P2W18Ni4 to the porphyrin ring active center in PCN-222, promoting the electro-reduction of CO2 activity. By contrast, P2W18Zn4 may accumulate electrons from PCN-222, thus facilitating the hydrogen evolution reaction (HER). This work reveals the critical role of sandwich-type POMs in manipulating the electron transfer pathway during the electrocatalytic process. Our findings would broaden the scope of POM applications in electrochemical carbon dioxide reduction. [ABSTRACT FROM AUTHOR]

Reactions between alkali metal hydrides MH (M = Li, Na, or K) and carbon dioxide (CO 2 ) at room temperature were systematically investigated for the first time. It was found that the raw alkali metal hydrides did not react with CO 2 under static-pressure conditions at room temperature, but the mechanically activated alkali metal hydrides reacted with CO 2 and released large amounts of hydrogen (H 2 ). Under the same ball-milling conditions, the order of reactivity of the alkali metal hydrides with CO 2 was KH > NaH > LiH. The particle size of the activated alkali metal hydrides had a large influence on the reactivity of the alkali metal hydrides with CO 2 . During the reactions, CO 2 was reduced by alkali metal hydrides, generating elemental carbon, alkali metal oxides and H 2 , and it was consumed by alkali metal oxides, forming carbonates. [ABSTRACT FROM AUTHOR]

In this study, the superior effect of RbF on reducing the hydrogen desorption operating temperature of the Li N H system was demonstrated. By doping 5 mol% RbF in the LiNH 2 LiH system, we obtain the lowest hydrogen desorption peak temperature (211 °C) at a heating rate of 5 °C/min, which is approximately 69 °C lower than that of the pristine LiNH 2 LiH system. Moreover, the system starts to desorb H 2 at 120 °C, which is the lowest hydrogen desorption onset temperature. The hydrogen desorption peak and onset temperatures can be further decreased by doping more RbF. It is proposed that the RbH produced during heat treatment improves the dehydrogenation properties of the RbF-doped LiNH 2 LiH sample. [ABSTRACT FROM AUTHOR]

In this study, we first examined the hydrogen release, uptake, and reversibility properties of the KLi 3 (NH 2 ) 4 -4LiH system and elucidated the influence of potassium cations' substitution into LiNH 2 on the hydrogen storage properties of the LiNH 2 -LiH composite. Our results show that mixing of the potassium cations into LiNH 2 can destabilize LiNH 2 , therefore decreasing the hydrogen desorption temperature and enhancing hydrogen desorption rate of the LiNH 2 -LiH system. Notably, the KLi 3 (NH 2 ) 4 -4LiH composite exhibits a superior cycling stability compared with the LiNH 2 -LiH composite prepared under the same condition. [ABSTRACT FROM AUTHOR]

In this study, the hydrogen desorption properties for the reactions between 1 mol% MNH-added (M = Li, Na, and K) lithium hydride and NH (0.5 MPa, NH/LiH = 1 mol/mol) at 100 °C were systematically investigated to design a LiH-NH hydrogen storage system with better kinetic properties. It is found that all of the alkali metal amide additives can improve the hydrogen desorption kinetics of the LiH-NH system, among which, LiNH shows the best effect. As compared to the other LiNH-added composition, the 1 mol% LiNH-added composition shows the best effect on improving the desorption kinetics of the LiH-NH system. According to the kinetic analysis, it is proposed that the effect of LiNH on the hydrogen desorption kinetics would be mainly due to physical effect. [ABSTRACT FROM AUTHOR]

Capturing CO 2 using clamshell/eggshell-derived CaO adsorbent can not only reduce carbon emissions but also alleviate the impact of trash on the environment. However, organic acid was usually used, high-temperature calcination was often performed, and CO 2 was inevitably released during preparing CaO adsorbents from shell wastes. In this work, CaO-based CO 2 adsorbent was greenly prepared by calcium-induced hydrogenation of clamshell and eggshell wastes in one pot at room/moderate temperature. CO 2 adsorption experiments were performed in a thermogravimetric analyzer (TGA). The adsorption performance of the adsorbents obtained from the mechanochemical reaction (BM-C/E-CaO) was superior to that of the adsorbents obtained from the thermochemical reaction (Cal-C/E-CaO). The CO 2 adsorption capacity of BM-C-CaO at 650 °C is up to 36.82 wt%, but the adsorption decay rate of the sample after 20 carbonation/calcination cycles is only 30.17%. This study offers an alternative energy-saving method for greenly preparing CaO-based adsorbent from shell wastes. • CO 2 adsorbent was prepared by calcium-induced hydrogenation of shell wastes. • Both mechanochemical and thermochemical methods were used. • The CO 2 adsorption capacity of BM-C-CaO at 650 °C is as high as 36.82 wt%. • The adsorption decay rate after 20 carbonation/calcination cycles is only 30.17%. • This study offers a green method for preparing CO 2 adsorbent from shell wastes. [ABSTRACT FROM AUTHOR]

In this study, the hydrogen desorption properties for the reactions between lithium hydride with different particle sizes and NH 3 (0.5 MPa, NH 3 /MH = 1 mol/mol) at 50–200 °C were systematically investigated to design the LiH–NH 3 hydrogen storage system with better kinetic properties. Moreover, various kinds of potassium compounds were also examined as potential catalysts to improve the kinetic properties of the hydrogen desorption reaction in the system. It is found that the kinetic properties of the hydrogen desorption in the LiH–NH 3 system are improved with the particle size of LiH reducing or the reaction temperature increasing. KBr, KCl, KF, and KOH are effective to enhance the kinetic properties, among which, KBr shows the best effect. [ABSTRACT FROM AUTHOR]

To avoid the agglomeration of iron NPs and improve the dispersion of Fe SAs, we employed a mixed-ligand strategy to regulate the iron content in PCN-224(ZnxFey) and PCN-222(ZnxFey). Thanks to the sublimation of Zn and the Kirkendall effect, uniform dispersions of Fe SAs with 1.04–1.06 wt% were obtained in the pyrolysis products Zn0.5Fe0.5–N–C-224 and Zn0.5Fe0.5–N–C-222 with excellent CO2 → CO activity, super-stability, and recyclability. [ABSTRACT FROM AUTHOR]

Ni/MgO DFMs for CO 2 capture and methanation were mechanochemically synthesized in one step at room temperature without using any solvent and NO 2 /CO 2 emission. [Display omitted] • The Ni/MgO DFMs are mechanochemically synthesized in one step at room temperature. • Integrated CO 2 capture and methanation over the Ni/MgO DFMs are investigated isothermally. • The CO 2 uptake and CH 4 yield over the 80Ni/MgO DFM at 300 ℃ are 0.37 and 0.27 mmol/g. • Cyclic tests exhibit that the ICCU-M performance over the Ni/MgO DFMs is stable. • This study offers an alternative, green, and sustainable strategy to acquire DFMs. Storing and in-situ hydrogenating CO 2 to CH 4 by dual functional materials (DFMs) is an efficient solution to alleviate the greenhouse effect and energy shortage. However, in the multi-step preparation process of DFMs, high-temperature calcination is usually required, solvent is used, and NO 2 /CO 2 is inevitably emitted. In this work, we first reported that the Ni/MgO DFMs could be mechanochemically synthesized in one step at room temperature by magnesium-induced hydrogenation of Ni-mixed magnesium carbonate without using any solvent and NO 2 /CO 2 emission. Integrated CO 2 capture and methanation performance of the Ni/MgO DFMs are investigated isothermally in a TG-MS apparatus and a fixed bed reactor. The CO 2 uptake and CH 4 yield over the 80Ni/MgO DFM at 300 ℃ are 0.37 mmol/g and 0.27 mmol/g, respectively, with a CO 2 conversion of 73.0 % and CH 4 selectivity of 100 %. After 5 consecutive CO 2 capture and methanation cycles at 300 ℃, the CO 2 uptake and CH 4 yield over the 50Ni/MgO DFM still are 0.26 mmol/g and 0.18 mmol/g, respectively, with a CO 2 conversion of 69.2 % and CH 4 selectivity of 100 %. Furthermore, the mechanism of CO 2 adsorption, activation, and hydrogenation to methane over the Ni/MgO DFM is systematically investigated by using density functional theory (DFT) calculations. This study offers an alternative, green, and sustainable strategy to acquire DFMs for CO 2 capture and methanation. [ABSTRACT FROM AUTHOR]

Summary: We systematically studied the thermochemical behaviors of alkali metals under the carbon dioxide (CO2) atmosphere and first investigated the hydromethanation performance of the alkali metal carbonate@carbon product formed in the reaction of CO2 with alkali metals. The on‐set reaction temperature of alkali metals with CO2 is at about 466, 584, and 595°C, respectively, following Li < Na < K. The experimental results indicate that COx‐free methane can be selectively and efficiently generated by hydrogenation of these carbonate@carbon composites at 450°C without a catalyst. Among these carbonate@carbon composites, the Li2CO3@carbon composite shows superior methanation performance. The selectivity of methanation is near 100%. The yield and content of methane are able to reach 30.3% and 26.6 mol%, respectively. This work provides an alternative method to produce methane, utilizing CO2 resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanochemical hydrogenation of shell wastes was studied at room temperature. • Alkaline metals can selectively assist the hydrogenation of shell wastes to CH 4. • The calcium metal has a better effect and the methane yield can reach 45.04%. • By doping Ru the methane yield of shell wastes can be improved to 54.76%. • This study provides a method to eliminate shell wastes and produce CH 4 fuel. Producing clean fuel using shell wastes (eggshell and clamshell) can eliminate food waste and alleviate the energy shortage. Mechanochemical hydrogenation of eggshell/clamshell was investigated at room temperature. The results show that the alkaline earth metals can effectively assist the hydrogenation of shell wastes to CH 4. The calcium metal has a better effect, and the methane yield for the calcium-assisted hydrogenation of clamshell and eggshell reaches 45.04% and 33.30% with 100% CH 4 selectivity. At the same time, the calcium-assisted methanation of shell wastes in the presence of transition metals (Fe, Co, Ni, Ru) was investigated. By doping Ru, the methane yield of clamshell and eggshell was improved to 52.62% and 54.76%, respectively. The milling time, rotating speed, hydrogen pressure, and the species of the doped transition metals influence the calcium-assisted methanation of shell wastes. This study provides an alternative method to eliminate shell wastes and produce clean CH 4 fuel at room temperature. [ABSTRACT FROM AUTHOR]

The eCO2RR activity is correlated to the internal structural character of the catalyst. We employed two types of structural models of porphyrin-based MOFs of PCN-222(Cu) and PCN-224(Cu) into heterogeneous catalysis to illustrate the effect of structural factors on the eCO2RR performance. The composite catalyst PCN-222(Cu)/C displays better activity and selectivity (η = 450 mV, FEHCOOH = 44.3%, j = 3.2 mA cm−2) than PCN-224(Cu)/C (η = 450 mV, FEHCOOH = 34.1%, j = 2.4 mA cm−2) for the CO2 reduction to HCOOH in the range of −0.7–−0.9 V (vs. RHE) due to its higher BET surface area, CO2 uptake, and a larger pore diameter. It is interesting that PCN-224(Cu)/C displays better performance in the range of −0.4–−0.6 V (vs. RHE) due to its greater heat of adsorption, Qst and a higher affinity for CO2 molecule, which could promote the capture of CO2 onto the exposed active sites. As a result, PCN-224(Cu)/C exhibits better stability for the long-term electrolysis. [ABSTRACT FROM AUTHOR]

Ammonia is a vital intermediate in the hydrogen desorption process of Metal-N-H system. KH has strong reactivity with NH 3 to form KNH 2. We speculate that KNH 2 is also an intermediate formed during hydrogen desorption of the potassium-doped M-N-H systems. In this research, the dehydrogenation performance of the KNH 2 -doped LiNH 2 and LiH composition was first studied. Compared with the broad dehydrogenation curve of the composite material of LiNH 2 and LiH without the catalyst, the dehydrogenation curve of 0.05 mol KNH 2 -doped composite material was significantly narrowed. The initial and peak dehydrogenation temperature of the composite to which 0.05 mol of KNH 2 was added was lowered remarkably. Besides, the cyclic dehydrogenation properties of the LiNH 2 and LiH system was also significantly enhanced by the introduction of KNH 2. The cyclic conversion of KNH 2 to KH is the main reason for the enhancement of the hydrogen evolution performance of the LiNH 2 –LiH system doped with KNH 2. We found the KNH 2 -doped Li–N–H system exhibits similar dehydrogenation property with that of the KH-doped Li–N–H system. This work proves that KNH 2 plays a key role in improving the hydrogen desorption performances of the potassium-doped M-N-H systems. Image 1 • Hydrogen desorption properties of the KNH 2 -doped Li–N–H system was examined. • Hydrogen desorption kinetics are significantly enhanced by introducing KNH 2. • The dehydrogenation temperature is lowered drastically. • The improved properties induce from the cyclic conversion from KNH 2 to KH. • KNH 2 may be formed during dehydrogenation of the potassium-doped M-N-H system. [ABSTRACT FROM AUTHOR]

Many efforts have been made to study the reactions of the borohydride with CO 2 in solution. However, it is scarce to achieve the hydrogenation of CO 2 using borohydrides as hydrogen source by the solid-gas direct reaction in the condition of ball milling under ambient temperature. Herein, we investigated the solid-gas noncatalytic reaction of ABH 4 (A = Li or Na) with CO 2 under mechanochemical conditions for the first time. It is found that hydrogen and trimethylborane are formed in the gas phase, as well as borate, formate, and methoxy species are formed in the solid phase. For the reaction of alkali borohydride with CO 2 , hydrogen and trimethylborane are formed in the gas phase, as well as borate, formate, and methoxy species are formed in the solid phase. Image 1 • The solid-gas reaction of alkali borohydride with CO 2 was investigated. • The reaction is carried out at ambient temperature under mechanochemical condition. • The hydrogen and trimethylborane are formed in the gas phase. • The borate, formate, and methoxy species are formed in the solid phase. • The work provides a new method for converting CO 2 using borohydrides. [ABSTRACT FROM AUTHOR]

A 3D chemically stable MOF of {[Cd1.5(DBPT)(DiPyDz)(H2O)]·3.5H2O}n (1) was successfully synthesized by a hydrothermal process, with the help of multifunctional ligand of H3DBPT (3-(3,5-dicarboxylphenyl)-5-(4-carboxylphenyl)-1-H-1,2,4-triazole) and bridging ligand of 1,2-di(pyridine-4-yl)diazene (DiPyDz). Characterizations of PXRD, FT-IR, TG and PL analysis for compound 1 were implemented. The overall structure maintains thermally stable up to 354 °C and keeps structural stability in common solvents after 48 h immersion. Most strikingly, it could maintain the crystallinity in water even for 10 days. It exhibits strong emission peak centered at 412 nm upon excitation at 280 nm, which could be attributed to the intra-ligand charge transfer of the H3DBPT ligand. It has proved itself an efficient sensor not only for acetone at low concentration but also for Fe3+ ion. The detection limit is estimated to be 0.0013% (v/v%) for the acetone, and 78 ppb for the Fe3+ ion, respectively. The KSV value for sensing Fe3+ ion is calculated to be 4.78 × 105 M−1, which is the third top one among the reported excellent MOFs-based sensors. The sensing performance is not affected even in the existence of interference metal ions, which reflects the high application potentials for the effective detection of Fe3+ in an aqueous system. [ABSTRACT FROM AUTHOR]

Visible‐light driven photoconversion of CO2 into energy carriers is highly important to the natural carbon balance and sustainable development. Demonstrated here is the adenine‐dependent CO2 photoreduction performance in green biomimetic metal–organic frameworks. Photocatalytic results indicate that AD‐MOF‐2 exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution, and is more than two times higher than that of AD‐MOF‐1 (179.0 μmol g−1h−1) in acetonitrile solution. Significantly, experimental and theoretical evidence reveal that the CO2 photoreduction reaction mainly takes place at the aromatic nitrogen atom of adenine molecules through a unique o‐amino‐assisted activation rather than at the metal center. This work not only serves as an important case study for the development of green biomimetic photocatalysts used for artificial photosynthesis, but also proposes a new catalytic strategy for efficient CO2 photoconversion. Eco‐friendly terms: Two biomimetic metal–organic frameworks (MOFs) were assembled with eco‐friendly components and used as photocatalysts for CO2‐to‐HCOOH conversion. One of the synthesized MOFs exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution. [ABSTRACT FROM AUTHOR]

Visible‐light driven photoconversion of CO2 into energy carriers is highly important to the natural carbon balance and sustainable development. Demonstrated here is the adenine‐dependent CO2 photoreduction performance in green biomimetic metal–organic frameworks. Photocatalytic results indicate that AD‐MOF‐2 exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution, and is more than two times higher than that of AD‐MOF‐1 (179.0 μmol g−1h−1) in acetonitrile solution. Significantly, experimental and theoretical evidence reveal that the CO2 photoreduction reaction mainly takes place at the aromatic nitrogen atom of adenine molecules through a unique o‐amino‐assisted activation rather than at the metal center. This work not only serves as an important case study for the development of green biomimetic photocatalysts used for artificial photosynthesis, but also proposes a new catalytic strategy for efficient CO2 photoconversion. [ABSTRACT FROM AUTHOR]

Abstract An interesting chemically stable metal-organic framework, {(NC 2 H 8) 2 [Cd(DMIPA)]·xG} n (G=guest molecules of H 2 O and DMA, DMA= N , N -Dimethylacetamide) (1), featuring a 4-connected uninodal {42.64} topology and 18 Å × 18 Å snowflake-like channels along the c axis with exposed thioether groups, was assembled by employing a tetratopic polycarboxylate ligand of 5,5΄-thiobisophthalic acid (H 4 DMIPA). Ligand-based photoluminescence and solvent-dependent fluorescent intensities were exhibited in compound 1. Most strikingly, it showed remarkable sensitivity and selectivity toward Fe3+ ions under the presence of other metal ions. The photoluminescence quenching could be detected at a very low concentration of 1.62 ppm, and the maximum quenching efficiency was found to be 97.2% at 0.175 mM. Significantly, compound 1 can be recycled after use. The fluorescence intensity and quenching percentage of 1 exhibited very little changes after being used for ten successive cycles (I 0 = 6349–6093, and QP = 95.4–96.2%), indicating that 1 is a very promising MOFs-based sensor with remarkable sensitivity, selectivity, and reusability towards Fe3+ ions. Graphical abstract An interesting chemically stable metal-organic framework, {(NC 2 H 8) 2 [Cd(DMIPA)]·xG} n (G=guest molecules of H 2 O and DMA, DMA= N , N -Dimethylacetamide) (1), featuring a 4-connected uninodal {42.64} topology and 18 Å × 18 Å snowflake-like channels along the c axis with exposed thioether groups, was assembled by employing a tetratopic polycarboxylate ligand of 5,5΄-thiobisophthalic acid (H 4 DMIPA). fx1 Highlights • A chemically stable anionic framework with exposed thioether groups in the 18 Å × 18 Å snowflake-like channels was assembled. • It showed remarkable sensitivity and selectivity toward Fe3+ ions under the presence of other metal ions. • The photoluminescence quenching could be detected at a very low concentration of 1.62 ppm. • The maximum quenching efficiency was found to be 97.2% at 0.175 mM. [ABSTRACT FROM AUTHOR]

Using the methodology of extension of reduced transition metal-grafted ε-Keggin polyoxoanions with two types of terphenyl-based tricarboxylates of H3L1 (3,5′,3′′-position substitution) and H3L2 (4,5′,4′′-position substitution) we isolated two (3,6)-connected 3D polyoxometalate-based metal–organic frameworks, [TBA]3[H3PMo12O40][Zn4L2] (1, YZU-105), and [TPA]3[H3PMo12O40][Zn4L1]·0.5H2O (2, YZU-106) (H3L1 = [1,1′;3′,1′′-terphenyl]-3,5′,3′′-tricarboxylic acid; H3L2 = [1,1′;3′,1′′-terphenyl]-4,5′,4′′-tricarboxylic acid; TBA = tetrabutylammonium; TPA = tetrapropylammonium). In both compounds, the building block was the dimerized form of Zn4-{ε-H3PMo12O40}. Such dimerization left six anchoring points for each dimer and, as a result, a 6-connected node was formed. Compounds 1 and 2 exhibited topologies of (4·85)3(4·82)6 and (65·10)3(63)6, respectively. This work illustrates that use of tri-carboxylate substitutions in different positions (3,5′,3′′-position/4,5′,4′′-position) in tripodal terphenyl-based ligands allows different extents of twisting of the peripheral aromatic ring with respect to the central ring, thereby giving rise to different extending directions and symmetries. [ABSTRACT FROM AUTHOR]

In this work, we report a novel, simple and convenient method for CO 2 methanation and synthesis of hydrogen and methane fuel mixtures at room temperature. CO x -free hydrogen and methane fuel mixtures have been successfully generated for the first time in one pot at room temperature through the solid/gas mechanochemical reactions of selected light metal hydrides with CO 2 . It is noted that methane is the sole hydrocarbon product in the mechanochemical reactions of selected light metal hydrides with CO 2 , which suggests that the mechanochemical reduction of CO 2 by light metal hydrides is highly selective. The yield and mole fraction of methane in the gas product depend mainly on the species of light metal hydride, rate and duration of ball milling, and CO 2 pressure. [ABSTRACT FROM AUTHOR]

In this paper, the hydrogen storage properties of the LiNH 2 LiH system doped with K 2 TiF 6 were investigated and discussed. Interestingly, the hydrogen storage properties are significantly enhanced by introducing K 2 TiF 6 into the LiNH 2 LiH system. By doping 5 mol% K 2 TiF 6 in the LiNH 2 LiH system, we obtain the hydrogen desorption peak temperature (233 °C) at a heating rate of 10 °C min −1 , which is approximately 66 °C lower than that of the pristine LiNH 2 LiH system. Moreover, the system begins to desorb H 2 at 75 °C, which is approximately 124 °C lower than in the pristine LiNH 2 LiH system. The isothermal desorption kinetics at 250 °C and 300 °C clearly reflects the dramatically improved kinetic properties. Additionally, the reversibility of the LiNH 2 LiH system can be drastically enhanced by adding K 2 TiF 6 . We propose that the dehydrogenation property of the K 2 TiF 6 -doped LiNH 2 LiH sample is improved by the synergetic effects of K, Ti and F. [ABSTRACT FROM AUTHOR]

Four three-dimensional (3D) coordination complexes on the basis of 4-halogenated isophthalic acid and two types of flexible and semiflexible N-donor ligands, formulated as {[Zn(bix)(4-Br-ip)]·H 2 O} n ( 1 ), {[Co(bix)(4-Br-ip)]·0.5H 2 O} n ( 2 ), [Zn(bbi)(4-Br-ip)] n ( 3 ) and [Co(bbi)(4-Cl-ip)] n ( 4 ), (4-Br-H 2 ip = 4-bromoisophthalic acid, 4-Cl-H 2 ip = 4-chloroisophthalic acid, bix = 1,4-bis(imidazol-1-yl-methyl)benzene, bbi = 1,1 ′ -(1,4-butanediyl)bis(imidazole)), have been synthesized and characterized by elemental analyses, IR spectra, single-crystal and powder X-ray diffraction analyses. Compounds 1 and 2 possess the same 4-connected 6 6 net. Compounds 3 and 4 are isostructural and exhibit the 4-connected 4 12 topology. The thermal stabilities for 1 – 4 and photoluminescence properties for the d 10 metal centers were discussed in detail. [ABSTRACT FROM AUTHOR]

A new Cd(II) coordination polymer has been prepared by solvothermal synthesis and characterized by single-crystal X-ray diffraction, IR, and element analysis. Complex [Cd2·BTT·Cl·(H2O)2]n (1) [H3BTT = 1,3,5-tris(2H-tetrazol-5-yl)benzene] is monoclinic, space group P217sol;c with a = 10.601(11) Å, b = 15.5428(16) Å, c = 9.0083(9) Å, β = 106.117(3)°, V = 1426.0(3) Å3. The final refinment gave R = 0.0192, and wR = 0.0473 for reflections with I > 2σ(I). Single-crystal X-ray diffraction analysis reveals that the compound 1 is a novel three-dimensional framework, featuring three types of connections of the tetrazole ring. [ABSTRACT FROM AUTHOR]

In this paper, the influence of multi-walled carbon nanotube (MWCNT)-doping on the hydrogen storage properties of the Li 3 N system was systematically investigated. Compared with the pure Li 3 N sample, the MWCNT-doped Li 3 N sample shows faster hydrogen absorption and desorption kinetics and a drastically improved cycling stability. Along with increasing MWCNT content, the hydrogen storage improvement becomes more apparent. When the MWCNT doping level reaches 10 mol%, the enhancement effect is significant. The improved hydrogen storage properties of the Li 3 N system by MWCNT-doping can be reduced to the physical effect of ball milling, the increased specific surface area and large pores as well as the good thermal conductivity of MWCNTs. [ABSTRACT FROM AUTHOR]

The coordination characteristics of 4-bromoisophthalic acid (4-Br-H 2 ip) have been investigated in a series of Cd II -based frameworks. Hydrothermal reactions of Cd II salts and 4-Br-H 2 ip together with flexible or semiflexible N-donor auxiliary ligands resulted in the formation of four three-dimensional coordination complexes with diverse structures: {Cd(bix) 0.5 (bix) 0.5 (4-Br-ip)]·H 2 O} n ( 1 ), [Cd(bbi) 0.5 (bbi) 0.5 (4-Br-ip)] n ( 2 ), {[Cd(btx) 0.5 (4-Br-ip)(H 2 O)]·0.5CH 3 OH·H 2 O} n ( 3 ) and {[Cd(bbt) 0.5 (4-Br-ip)(H 2 O)]·3·5H 2 O} n ( 4 ). These compounds were characterized by elemental analyses, IR spectra, single-crystal and powder X-ray diffraction. They displayed diverse structures depending on the configuration of the 4-connected metal node, the coordination mode of the 4-Br-H 2 ip, the coordination ability and conformationally flexibility of the N-donor auxiliary. Compound 1 exhibits 3-fold interpenetrated 6 6 topology and compound 2 has a 4 12 topology. Compounds 3 – 4 have similar 3D pillar-layered structures based on 3,4-connected binodal net with the Schläfli symbol of (4·3 8 ). The thermal stabilities and photoluminescence properties of them were discussed in detail. [ABSTRACT FROM AUTHOR]

Interestingly, an obvious enhancement of the hydrogen storage property is achieved by introducing KF into the LiNH 2 –LiH system, while KCl, KBr or KI does not show obvious effect on improving the hydrogen storage properties of the LiNH 2 –LiH system. In comparison with that of the LiNH 2 –LiH composite, the hydrogen desorption curve of the LiNH 2 –LiH–0.05 KF composite becomes sharp and the dehydrogenation onset and peak temperatures are decreased by about 36 °C and 38 °C, respectively. The cyclic capacity and desorption kinetic of the LiNH 2 –LiH–0.05 KF composite in the tenth cycle are still much better than that of the LiNH 2 –LiH composite in the second cycle. Cyclic performance can be improved at least 4 times by addition of 5 mol% KF. Detailed structural investigations reveal that during the heat-treatment, the doped potassium fluoride can react with LiH and convert to potassium hydride, which induces the improvement in hydrogen storage properties of the LiNH 2 –LiH system. [ABSTRACT FROM AUTHOR]

Liquid ammonia electrolysis is conducted out at ambient temperature using different ammonium salt electrolytes with and without the reference electrode. It is determined that electrolytes containing NH 4 + increase the current density and reduce the solution resistance. Moreover, ammonium salts of NH 4 Br, NH 4 NO 3 and NH 4 Cl preserve >80% current efficiency and a 0.6–0.8 mL min −1 average rate of H 2 generation during chronopotentiometry tests at 120 mA cm −2 for 3 h. A minimum electrolysis voltage ( E min ) of ca . 1.2 V is required for the NH 4 Cl electrolyte when using Pt-foil as the anode and cathode. To decrease the overpotential of the anode reaction, five types of electrocatalysts were prepared and characterized: Pt-black, Rh, Pt–Ir, Rh–Pt and Ph–Pt–Ir alloys. Trimetallic Rh–Pt–Ir and bimetallic Pt–Ir, Rh–Pt (1:1) alloy electrodes exhibit a combined benefit of better activity and minimized deactivation. The ternary Rh–Pt–Ir alloy anode shows the best electrocatalytic activity with the lowest E min of ca . 0.47 V and highest current density of 46.9 mA cm −2 at 2.0 V. In comparison with the Pt-foil anode, the E min is reduced by two-thirds, and the current density is increased two-fold. [ABSTRACT FROM AUTHOR]

The preparation of clean fuel or CO 2 adsorbents using industrial and domestic garbage is an alternative way of meeting global energy needs and alleviating environmental problems. Herein, H 2 -mixed CH 4 fuel and CaO-based CO 2 sorbent were first prepared in one pot by the mechanochemical reaction of pretreated clamshell or eggshell wastes (carbon and calcium source) with calcium hydride (hydrogen source) at room temperature. In the above reactions, CH 4 was the sole hydrocarbon product, and its yield reached 78.23%. The H 2 /CH 4 ratio of the produced H 2 -mixed CH 4 fuel was tunable according to the need by changing the reaction conditions. It is inspiring that the simultaneously formed solid CaO/carbon products were efficient CaO-based sorbents, which possessed a higher CO 2 adsorption capacity (49.81–58.74 wt.%) at 650 °C and could maintain good adsorption stability in 30 carbonation/calcination cycles (average activity loss per cycle of only 1.6%). The three achievements of the idea are that it can simultaneously eliminate clamshell or eggshell wastes, obtain valuable clean fuel, and acquire efficient CaO-based sorbents. H 2 -mixed CH 4 fuel and CaO-based CO 2 sorbent were prepared simultaneously by the mechanochemical reaction of shell waste with calcium hydride. [Display omitted] • Mechanochemical reaction of shell wastes with CaH 2 was first studied. • H 2 -mixed CH 4 fuel and CaO-based CO 2 sorbent were successfully prepared in one pot. • CH 4 was the sole hydrocarbon product and its yield can reach as high as 78.23%. • The CaO products possess higher CO 2 absorption capacity and cycling stability. • This process eliminates shell wastes, obtains clean fuel and efficient CO 2 sorbents. [ABSTRACT FROM AUTHOR]

A new 2D network formulated as [TBA][HPMoMoOZn][CH(COO)] ( 1) containing linear inorganic chain {ε-HPMoMoOZn} has been synthesized and structurally characterized by FT-IR, thermal analysis, single crystal and powder X-ray diffraction. Compound 1 shows remarkable electrocatalytic activity towards bromate reduction, nitrite reduction and ascorbic acid oxidation. Moreover, the proton conduction behavior of 1 has also been investigated. [ABSTRACT FROM AUTHOR]

By introducing a bridging ligand of 5-methylisophthalic acid (shortened as 5-mip) into the tetrahedral Zn-ε-Keggin system, a new 2D network of [TBA][HPMoMoOZn][CH(COO)] ( 1) was synthesized under hydrothermal condition. It was characterized by FT-IR, BET, TGA/DSC-MASS analysis, powder X-ray diffraction and single-crystal X-ray diffraction, respectively. Besides, compound 1 shows remarkable electrocatalytic activity towards bromate reduction. [ABSTRACT FROM AUTHOR]

A new ɛ-Keggin polyoxometalate based metal-organic framework, [TBA] 3 [H 4 PMo 8 VMo 4 VIO 40 Zn 4 ](HTPT) 2 (1) (H 3 TPT = 1,1′:4′,1″-terphenyl-3,4″,5-tricarboxylic acid, TBA+ = tetrabutylammonium ion) was synthesized under hydrothermal conditions. The tetrahedral Zn 4 -ε-Keggin is connected through angular HTPT2− to form a 2D entangled structure with 2-fold interpenetration. The whole network displays a staggered layer structure in AB/CD/EF/GH/AB/CD/EF/GH arrangement with extensive hydrogen bonding and intermolecular interactions. More interestingly, compound 1 exhibited good hydrogen evolution reaction (HER) activity in an acidic medium, with a Tafel slope of 68 mV·dec−1 and an η 10 of 417 mV. It showed an excellent long-term stability, which could maintain its catalytic activity after 1000 cycles. [Display omitted] • A new compound has been constructed from Zn 4 -ε-Keggin node and HTPT2−. • It exhibits an interesting 2D entangled structure with 2-fold interpenetration. • The compound displays excellent catalytic ability for hydrogen evolution reaction. • After 1000 cycles, the compound can still maintain its catalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • ▶ CaO-based adsorbent is sustainably synthesized by hydrogenation reduction of CaCO 3. • ▶ The prepared CaO@C and CaO@MgO@C composites are high performance CO 2 adsorbent. • ▶ They exhibit higher CO 2 uptake capacity than that of the ball-milled CaO at 650 °C. • ▶ They also show faster adsorption rate and better cycling stability. • ▶ The work provides a novel and sustainable method to prepare CaO-based CO 2 adsorbent. The development of inert additive-doped CaO-based CO 2 adsorbents is a promising method to obtain efficient CO 2 adsorbents, while multiple programs are frequently involved, the organic solvent is often used, and CO 2 is sometimes released in the process of preparation. In this study, we first report that inert additive-doped CaO-based adsorbents can be synthesized in one pot by the mechanochemical hydrogenation reduction of CaCO 3 producing methane and avoiding CO 2 emission. The prepared CaO@C and CaO@MgO@C composites are high-performance CO 2 adsorbents with high CO 2 adsorption capacity and superior cycling stability. The results show that the CO 2 capture capacities of the CaO@C and CaO@MgO@C composites are 19.14 and 14.53 wt% higher than that of the BM-CaO (37.07 wt%), respectively, at 650 °C carbonation for 2 h. Notably, the activity losses of the CaO@C and CaO@MgO@C composites after 30 cycles are about 47.93 and 29.33%, which are much lower than that of the BM-CaO (60.39%). The performance of the CaO@C and CaO@MgO@C adsorbents is comparable to that of adsorbents synthesized by the conventional methods, but this work provides novel, simple, solution-free, and sustainable strategies to synthesize effective CaO-based CO 2 adsorbents in one pot. [ABSTRACT FROM AUTHOR]

CO x -free H 2 -mixed CH 4 fuel was successfully prepared by thermochemical reduction of solid CO 2 (inorganic carbonates) with solid hydrogen (activated metal hydrides). [Display omitted] • Thermochemical reaction of carbonate with hydride was first investigated. • CO x -free H 2 -mixed CH 4 fuel was successfully prepared at moderate condition. • The CH 4 yield and content depend on reaction condition and reactant nature. • For carbonate-hydride system, CH 4 yield can reach 84.5% with 100% selectivity. • This work opens new way to in-situ synthesize H 2 -mixed CH 4 fuel utilizing CO 2. Converting CO 2 into methane is realistic and conducive to addressing environmental and energy issues. The mixture of hydrogen and methane shows superior combustion efficiency, while the investigation on the storage and in-situ preparation of hydrogen-mixed methane was neglected. In this work, thermochemical reduction of solid CO 2 (inorganic carbonates) with solid hydrogen (activated metal hydrides) was first investigated, and we successfully prepared CO x -free H 2 -mixed CH 4 fuel with high yields and selectivity. As respects to the inorganic carbonate-metal hydride systems, the volume energy density can reach as high as 12055.4 kJ/mol, CH 4 yield can reach 84.5% with approximate 100% selectivity, and the CH 4 content ranging from 8.6% to 88.1% is able to be tuned. It was confirmed that the nature of inorganic carbonates/hydrides, heating time and temperature, and the composition of the reaction mixture has a significant influence on methane yield and content. These results demonstrate that heat treatment of nanosized inorganic carbonates and activated metal hydrides is a promising process for in-situ preparation of H 2 -mixed CH 4 fuel and CO 2 utilization. [ABSTRACT FROM AUTHOR]

In this paper, we studied the mechanochemical reactions between a series of metal carbonates and metal hydrides in the absence of a catalyst and found that the alkaline earth metal carbonate-hydride systems show better methanation performances because these systems possess favorable thermodynamic properties. Among them, the CaCO 3 -MgH 2 system shows the best methanation performances. By tuning the reaction mixture composition and enhancing the rate and duration of ball milling, the CH 4 yield and content of the CaCO 3 -MgH 2 system can reach 89% and 90%, respectively, which are increased by 16% and 40%, compared to the best results in the previous reports. Image 1 • The mechanical reactions of metal carbonates with metal hydrides was investigated. • The alkaline metal carbonate can be effectively reduced to methane by the alkaline metal hydride. • The CaCO 3 -MgH 2 system shows the best methanation performances. • The CH 4 yield and content of the CaCO 3 -MgH 2 system can reach 89% and 90%. • The work provides a simple and efficient method for synthesizing H 2 -CH 4 fuel mixtures. [ABSTRACT FROM AUTHOR]

We report an efficient, convenient, solution-free method to achieve the room-temperature dehydrogenation of alkaline earth metal hydrides (MgH 2 and CaH 2). It is found, for the first time, that metal carbonates, which are readily available and cheap, can efficiently induce the hydrogen desorption of alkaline earth metal hydrides at room temperature under mechanical ball milling conditions. We demonstrate that the hydrogen yield and purity mainly depend on the nature of metal carbonates, rate and duration of ball milling, and reaction mixture composition. The best performances are obtained with the systems of MgCO 3 -MgH 2 and MgCO 3 -CaH 2 milled at 350 ​rpm for 12 ​h, with the CO x -free hydrogen yield of 94% and 90%. This work opens a new way to achieve the efficient dehydrogenation of alkaline earth metal hydrides at room temperature. It is found, for the first time, that metal carbonates can efficiently induce the hydrogen desorption of alkaline earth metal hydrides (MgH 2 and CaH 2) at room temperature under mechanical ball milling condition. Image 1 • Metal carbonates can induce the dehydrogenation of MgH 2 and CaH 2 at room temperature. • Hydrogen yield depends on the nature of metal carbonate and duration of ball milling. • Hydrogen yield also depends on rate of ball milling and reaction mixture composition. • For MgCO 3 -added MgH 2 and CaH 2 , hydrogen yields are achieved as high as 94% and 90%. • The work opens a new way to achieve the dehydrogenation of MgH 2 and CaH 2. [ABSTRACT FROM AUTHOR]

Metal–Organic Frameworks. MOFs containing the nucleobase adenine were used as photocatalysts for CO2‐to‐HCOOH conversion, as shown by Y.‐Q. Lan and co‐workers in their Communication on page 5226 ff. [ABSTRACT FROM AUTHOR]

Metall‐organische Gerüststrukturen. Metall‐organische Gerüste (MOFs) mit der Nucleobase Adenin fanden Verwendung als Photokatalysatoren für die Umwandlung von CO2 in HCOOH, wie Y.‐Q. Lan et al. in ihrer Zuschrift auf S. 5280 schildern. [ABSTRACT FROM AUTHOR]

In the study of the KH-added H2 storage system LiH-NH3 (KH-added LiH-LiNH2, KH-added LiNH2, and KNH2-added LiNH2), KLi3(NH2)4 is found to be an important intermediate formed in dehydrogenation and hydrogenation of the KH-added Li-N-H system. [ABSTRACT FROM AUTHOR]