Search

Template effect of the solvents plays a key role in metal-organic frameworks (MOFs) synthesis. In addition, Bi3+has a flexible and changeable coordination configuration, which is conducive to the construction of structurally diverse MOFs. Herein, we demonstrate that these features can be integrated into two stable bismuth-based porphyrin MOFs (named PFC-100 and PFC-101) with a wide range of light absorption. Further studies demonstrate that PFC-101 with weaker interactions of adjacent porphyrin planes achieves 22.2% photothermal conversion efficiency (PTCE), 1.5-fold higher than that of PFC-100 (14.3%) under 660 nm irradiation. This study may shed light on the impact of solvent templates on the synthesis of bismuth-based MOFs, not only enriching the MOFs library but also broadening the horizon of their potential applications.

Tuberculosis (TB) remains a major public health challenge, with research on new anti-TB drugs crucial for global TB elimination efforts. Here, we report a novel class of anti-TB agents. Especially, compounds 5band 5jexhibited the highest activity [minimum inhibitory concentration (MIC) H37Rv: 0.16 and 0.12 μg/mL]. Chiral resolution was performed on compounds 5band 5j; the isomers were evaluated for their activity and safety, confirming that the R-isomer 5bband 5jbdisplayed significant anti-TB activity (MIC H37Rv: 0.03–0.06 μg/mL; MDR-Mtb: 0.125–0.06 μg/mL) and low hERG toxicity. Further evaluations on 5bband 5jbdemonstrated good metabolic stability, favorable kinetic parameters and oral bioavailability (F: 56.7 and 63.8%, respectively). The results of in vivoactivity assessment indicate that 5bband 5jbexhibit protective and therapeutic effects on zebrafish larvae and adult zebrafish infected with Mycobacterium marinum. Based on these results, compounds 5bband 5jbare considered promising candidates for further in-depth studies.

The CO2reduction reaction (CO2RR) pathway significantly dictates the reversibility and overpotential of aprotic Li-CO2batteries; however, it has remained incompletely understood due to the lack of direct in situ spectroscopic evidence. Herein, the Li-CO2RR pathways at the model Au | dimethyl sulfoxide (DMSO) interface are interrogated using a combination of in situ isotope-labeled spectroscopy techniques and theoretical calculations. This obtained direct spectroscopic evidence presents that the primary CO2RR proceeds through the CO2-to-CO pathway (i.e., 2Li++ 2CO2+ 2e–→ CO + Li2CO3) initiated at a low overpotential (ca. 2.1 V vs Li/Li+), and the CO2-to-Li2C2O4pathway (i.e., 2Li++ 2CO2+ 2e–→ Li2C2O4) initiated at a high overpotential (ca. 1.7 V vs Li/Li+), where the potential-dependent pathways critically depend on the coverage of LiCO2intermediates. Simultaneously, the entire Li-CO2RR process is also accompanied by parasitic reactions to form gaseous C2H4with COOH* as the crucial intermediate, which is induced by the H+-abstraction reaction between the reactive LiCO2intermediate and the DMSO solvent. These fundamental insights enable us to establish a molecular picture for Li-CO2RR pathways in aprotic media and will serve as a crucial guideline for reversible Li-CO2electrochemistry.

Simultaneously harnessing the photogenerated electrons and holes to convert thiols into the value-added disulfides with the concomitant formation of H2represents a highly promising strategy for maximizing the conversion of solar energy into chemical energy. Herein, we report an effective catalytic system comprising CdS nanorods (NRs) and Ni-containing polyoxometalate (Na6K4[Ni4(H2O)2(PW9O34)2] (Ni4P2)) (Ni4P2/CdS), which exhibited efficient photocatalytic activities towards the near-unity dehydrocoupling of 4-methoxythiophenol (4-MTP) into disulfide and H2evolution. The photooxidative dehydrocoupling of 4-MTP can be finished after 4 h photocatalysis, leading to 98.39% conversion of 4-MTP with the yield of disulfide and H2reaching 24.45 and 25.96 μmol, respectively. The Ni4P2/CdS catalytic system also showed good photocatalytic recycling stability. Comprehensive experimental and characterization results indicated that the synergistic cooperation between CdS NRs and Ni4P2facilitated the separation and migration of the photogenerated electron-hole pairs, thereby improving the photocatalytic dehydrocoupling of 4-MTP to disulfide coupling with hydrogen production.

The conversion of solar energy into chemical fuels stands at the forefront of promising applications for metal-organic frameworks (MOFs), but the rapid recombination of photo-induced charge carriers within these frameworks poses a significant challenge to their photo-catalytic performance. Despite heterojunction construction has potential as a viable approach, its synthesis involves considerable complexity. Here, we present a distinct and well-defined phase junction based on polymorphic MOFs, achieved through an efficient one-pot synthesis process. This work not only paves the way for a robust platform for designing sophisticated MOFs complexes, but also illuminates the intricate hierarchical structure-function dynamics inherent in MOFs. The fabricated PCN-222-Ni@PCN-224-Ni (P@P) hybrid material exhibits extensive surface area, a porous matrix, and superior crystallinity. The harmonious alignment of the bandgap between PCN-222-Ni and PCN-224-Ni, establishing a phase junction for type-II carrier transfer, endows the resultant photocatalysts with exceptional visible-light-induced photoreduction capabilities for CO2, along with augmented stability. This significant advancement represents a significant milestone in the applications of MOFs, especially in harnessing solar energy for the production of sustainable chemical fuels through the process of CO2photo-conversion.

HOF-Ti1 achieved the high selectivity for NH3production of nitrate reduction reaction after investigating a series of HOFs via high-throughput mechanistic study.

The highly selective photoreduction of CO2into valuable chemical fuels such as CO has been considered as an effective strategy to address modern energy and environmental issues. In this work, we have adopted the well-established impregnation approach to construct a P2W15Ni3{Re(CO)3}3@NU-1000 composite by incorporating heterometallic-substituted P2W15Ni3{Re(CO)3}3polyoxometalate (POM) into the pores of metal-organic framework (NU-1000) host. Upon light irradiation, the resulting P2W15Ni3{Re(CO)3}3@NU-1000 composite can effectively photocatalyze CO2reduction, obtaining a CO production of 28982 μmol g−1with 93.5% selectivity during 10-h photocatalysis. The catalytic system exhibits great long-term recyclability and stability for at least four successive recycles. The proposed photocatalytic mechanism was confirmed by a series of photochemical and spectroscopic analyses.

A phosphorus-modified Sn/SnOxcore/shell (P-Sn/SnOx) catalyst, derived from in situ electrochemical reduction of amorphous Sn(HPO4)2, enhances CO2adsorption and improves free energy profile of formate formation, thus resulting in high CO2electroreduction performance.

Tuning catalyst microenvironments by electrolytes and organic modifications is effective in improving CO2electrolysis performance. An alternative way is to use mixed CO/CO2feeds from incomplete industrial combustion of fossil fuels, but its effect on catalyst microenvironments has been poorly understood. Here we investigate CO/CO2co-electrolysis over CuO nanosheets in an alkaline membrane electrode assembly electrolyser. With increasing CO pressure in the feed, the major product gradually switches from ethylene to acetate, attributed to the increased CO coverage and local pH. Under optimized conditions, the Faradaic efficiency and partial current density of multicarbon products reach 90.0% and 3.1 A cm−2, corresponding to a carbon selectivity of 100.0% and yield of 75.0%, outperforming thermocatalytic CO hydrogenation. The scale-up demonstration using an electrolyser stack achieves the highest ethylene formation rate of 457.5 ml min–1at 150 A and acetate formation rate of 2.97 g min–1at 250 A.

Feasible construction of cathode materials with highly dispersed active sites can extend the triple-phase boundaries, and therefore leading to enhanced electrode kinetics for CO2electrolysis in solid oxide electrolysis cell (SOEC). Herein, highly dispersed nickel species with low loading (1.0 wt%) were trapped within the La0.8Sr0.2FeO3–δ-Ce0.8Sm0.2O2–δviaa facial mechanical milling approach, which demonstrated excellent CO2electrolysis performance. The highly dispersed nickel species can significantly alter the electronic structures of the LSF-SDC without affecting its porous network and facilitate oxygen vacancy formation, thus greatly promote the CO2electrolysis performance. The highest current density of 1.53 A·cm−2could be achieved when operated under 800 °C at 1.6 V, which is about 91% higher than the LSF-SDC counterpart.

ABSTRACTClinically, the effective treatment for patients with acute ischemic stroke (AIS) is very limited. Therefore, this paper aims to investigate the mechanism how astragalus polysaccharide (APS) exerts protective effect against AIS and provide a new method for the treatment of AIS. Cell surface antigen flow cytometry and immunofluorescence were used to identify M1 and M2 microglia. Western blot was used to evaluate the expression of associated protein. Oxygen-glucose deprivation (OGD) was used to simulate the effect of AIS on rat microglia. The middle cerebral artery occlusion (MCAO) model was established to simulate the effect of AIS in vivo. Evans blue dye (EBD) was used to evaluate the permeability of blood–brain barrier (BBB). Western blot and cell surface antigen flow cytometry results showed that APS promoted the M2 polarization of rat microglia by inhibiting the expression of purinergic receptor (P2X7R). APS reversed the effect of OGD on the polarization of rat microglia M1/ M2 by regulating P2X7R. APS reversed the effect of MCAO on the polarization of rat microglia M1/ M2 in vivo. Furthermore, APS inhibited the expression of P2X7R by promoting the degradation of adenosine triphosphate (ATP) in the cerebral cortex of MCAO rats. In addition, APS contributed to maintain the integrity of BBB. Summarily, APS can reduce brain injury by promoting the degradation of ATP in microglia and inhibiting the expression of P2X7R after AIS.

Crystal engineering, as a burgeoning technology, has been widely used to construct metalloporphyrins biomimetic catalysts. Herein, a bimetallic metal-organic framework (MOF) was constructed by 4-(4-carboxyphenyl)-1,2,4-triazole ligand, Co2+and Zr4+metal ions by solvothermal reaction(named PFC-88). A N,N-chelation site was found between the two adjacent ligands in PFC-88, consequently a porphyrin-like structure was obtained through chelating Fe3+in this site by post-modification, named PFC-88-Fe. The result of a single crystal X-ray technology verified that Fe ions were successfully metalated in the N,N-chelation site of PFC-88, which is assisted by the X-ray absorption near-edge structure(XANES) spectra. An o-phenylenediamine oxidation reaction was applied to assessing the catalytic activity of PFC-88-Fe, in which the absorbance increases of phenazine-2,3-diamine at λ=418 nm were recorded by absorption spectroscopy in kinetic mode, exhibiting the application potential as a biomimetic catalyst.

With the battery-type anode and capacitor-type cathode, lithium-ion capacitors (LICs) are expected to exhibit both high energy and high power density but suffer from the mismatch of the electrode reaction kinetics and capacity. Herein, to alleviate the mismatch between the two electrodes and synergistically enhance the energy/power density, we design a method of microwave irradiation reduction to prepare graphene-based electrode material (MRPG/CNT) with fast ion/electron pathway. The three-dimensional structure of CNT intercalation to graphene inhibits the restacking of graphene sheets and improves the conductivity of the electrode material, resulting a rapid ion and electron diffusion channel. Due to its specific properties, MRPG/CNT materials can be used as both anode and cathode electrodes of LICs at the same time. As anode, MRPG/CNT shows a high capacity of 1200 mAh g–1as well as high rate performance. As cathode, MRPG/CNT displays a high capacity of 108 mAh g–1and the capacity retention of 100% after 8000 cycles. Coupling the prelithiated MRPG/CNT anode with MRPG/CNT cathode gives a full-graphene-based symmetric LIC, which achieves a high energy density of 232.6 Wh kg–1at 226.0 W kg–1, 111.2 Wh kg–1at the ultrahigh power density of 45.2 kW kg–1, and superior capacity retention of 86% after 5000 cycles. The structure design of this electrode provides a new strategy for alleviating the mismatch of LIC electrodes and constructing high-performance symmetrical LICs.

As one of the greatest inventions in the history of electrochemistry, the lithium-ion battery (LIB) has radically transformed human beings’ daily life by powering portable electronics and electric vehicles. When we look back upon the long and arduous effort devoted to the development of the LIB technology, it is found that the birth of LIBs could have been even earlier if reversible cycling of the graphite electrode had been realized in the propylene carbonate (PC) electrolyte, one of the few dominating electrolytes extensively used in nonaqueous electrochemistry long before the concept of LIBs. In this work, a functional electrolyte additive, that is, ethyl isothiocyanate, has been identified to enable the reversible Li+ion intercalation/de-intercalation into/out of the graphite electrode in PC electrolyte by forming a high-quality solid electrolyte interphase (SEI) on the graphite electrode. A wide range of advanced in situand ex situspectroscopic characterization techniques coupled with theoretical calculations have been employed to understand the SEI formation mechanism. The results reported here rejuvenate the promise of PC as the primary electrolyte solvent for LIBs by artificially rectifying the interfacial electrochemical processes.

Phosphorus atom-doped metal-free nitrogen catalyst can effectively promote the electrocatalytic reduction of carbon dioxide to generate carbon monoxide.

During the high-temperature oxygen evolution reaction for CO2electrolysis in solid oxide electrolysis cells (SOECs), the key elementary process of O2–transfer is restricted by the high anodic oxygen pressure thermodynamically, thus requiring a high external voltage [open-circuit voltage (OCV)] to drive the electrolysis reaction. Herein, electrochemical CH4reforming is introduced to the SOEC anode, which remarkably lowers the anodic oxygen pressure and OCV, finally reducing the energy demand from 3.12 to 0.11 kW h per cubic meter of CO. Meanwhile, atomically dispersed Ru species is anchored on the anode surface due to the strong metal–support interaction, which exhibits superior CH4reforming activity (90% of CO selectivity) and stability (300 h) to the infiltrated Ru nanoparticles and doped Ru species in the bulk lattice at 600 °C. This work proposes an efficient strategy to boost the SOEC performance thermodynamically and produce value-added chemicals at both the cathode and anode of SOEC simultaneously.

The rocking-chair lithium-ion capacitors (RLICs), composed of a battery-type cathode and capacitive-type anode, alleviates the issue of increased internal resistance caused by electrolyte consumption during the cycling process of the lithium-ion capacitors (LICs). However, the poor conductivity of cathode materials and the mismatch between the cathode and anode are the key issues that hinder its commercial application. In this work, a modification simplification strategy is proposed to tailor the conductivity of the cathode and matching characteristic with the anode. The in situ grown lithium manganate (LMO) is featured with a three-dimensional conductive network constructed by reduced graphene oxide (rGO). The optimized LMO/rGO composite cathode demonstrates an excellent rate performance, lithium-ion diffusion rate, and cycling performance. After assembling an RLICs with activated carbon (AC), the RLICs exhibits an energy density of as high as 239.11 Wh/kg at a power density of 400 W/kg. Even at a power density of 200 kW/kg, its energy density can maintain at 39.9 Wh/kg. These excellent electrochemical performances are mainly attributed to the compounding of LMO with rGO, which not only improves the conductivity of the cathode but also realizes a better matching with the capacitive-type anode. This modification strategy provides a reference for the further development of energy storage devices suitable for actual production conditions and application scenarios.

In this work, for the first time it is demonstrated that supported single Au in either a positive or a negative charge state can catalyze acetylene hydrochlorination competitively with regard to other reported Au catalysts by using first-principle calculations. The nitrogen and boron dopants on the single-walled carbon nanotube (SWCNT) not only behave as stable anchoring positions for the single Au but also effectively adjust the electronic structure of Au. It is revealed that Au becomes positively and negatively charged on nitrogen- and boron-doped SWCNT, respectively. The different charge state of Au directly influences the interactions with the reactants C2H2. Moreover, the charge transfer during C2H2adsorption exhibits an opposite effect for Au cation and anion. Therefore, the dopant on the support is effectively a tool to tune the properties of the supported single Au. The reaction obeys an Eley–Rideal-like mechanism, in which C2H2binds first, followed by HCl activation and product formation. Detailed reaction pathway analysis reveals that both positively and negatively charged Au are active acetylene hydrochlorination catalysts with comparable reaction barriers. The current work not only broadens the scope of Au catalysts in acetylene hydrochlorination, with the inclusion of negative Au, but also verifies the effectiveness of support doping to tune the catalytic performance.

A stable hierarchical porous metal–organic framework PCN-56 with abundant Lewis acid sites was synthesized by the low-temperature synthesis-induced defect formation method. It exhibits good adsorption capacity for dyes and high loading capacity toward macromolecular drugs.

The CO2photoconversion is sensitive to the local reaction environment, of which activity and selectivity can be regulated by the change of reaction systems. This paper focuses on investigating the photocatalytic CO2reduction behaviors of MOFs with the involvement of water under different reaction modes, including gas-solid and liquid-solid systems. The CO2photoreduction in a liquid-solid system shows high performance in generating HCOOH with the selectivity of 100%. In contrast, the gas-solid system referring to the synergistic interaction of MOFs and H2O vapor benefits to the formation of gas-phase products, such as CO and CH4. The possible mechanisms of photocatalytic CO2reaction in two modes were investigated by in-situFourier-transform infrared spectroscopy, which indicates that the distinction in reaction consequence may result from the difference in CO2chemisorbed modes and the proton provision. The choice of reaction system plays an important role in the achievement of high efficiency and selectivity for photocatalytic CO2reduction, which is of great practical value in real-world applications.

Solid oxide electrolysis cells provide a practical solution for the direct conversion of CO2to other chemicals (i.e. CO), however, an in-depth mechanistic understanding of the dynamic reconstruction of active sites for perovskite cathodes during CO2electrolysis remains a great challenge. Herein, we identify that iridium-doped Sr2Fe1.45Ir0.05Mo0.5O6-δ(SFIrM) perovskite displays a dynamic electrochemical reconstruction feature during CO2electrolysis with abundant exsolution of highly dispersed IrFe alloy nanoparticles on the SFIrM surface. The in situreconstructed IrFe@SFIrM interfaces deliver a current density of 1.46 A cm−2while maintaining over 99% CO Faradaic efficiency, representing a 25.8% improvement compared with the Sr2Fe1.5Mo0.5O6-δcounterpart. In situelectrochemical spectroscopy measurements and density functional theory calculations suggest that the improved CO2electrolysis activity originates from the facilitated formation of carbonate intermediates at the IrFe@SFIrM interfaces. Our work may open the possibility of using an in situelectrochemical poling method for CO2electrolysis in practice.The in situelectrochemical reconstructed IrFe@SFIrM interfaces facilitate the formation of carbonate intermediates and contribute to an enhanced CO2electrolysis performance in solid oxide electrolysis cells.

Urea groups are known to form strong hydrogen bonds with molecules containing atom(s) that can act as hydrogen bond acceptor(s). Thus, urea is a particularly interesting building block for designing receptors for neutral or charged guests. In the quest for new sensors with enhanced performance for the detection of nitro-substituted compounds, two pillared metal–organic frameworks containing urea functional groups were synthesized and structurally characterized. The sensing properties of these frameworks toward nitro-analytes were investigated and compared to each other. The study clearly reveals the importance of urea groups orientation inside the pore cavity of MOFs, as well as the supramolecular interactions between the interpenetrated networks. This work is interesting as it represents the first example of urea-functionalized MOFs for nitro-analytes recognition.

Perovskites with in situ exsolved metal nanoparticles have been extensively studied for CO2electrolysis in solid oxide electrolysis cell. However, exsolution process is strongly governed by the sluggish diffusion rate of cations and poor structural stability issues. Here we present a new exsolution process on redox stable Pr0.7Sr0.3Cr0.9Ni0.1O3−δ(PSCN) perovskite by topotactic exsolution. This process tends to generate host stoichiometric Pr0.7Sr0.3Cr0.9(FeNi)0.1O3−δperovskite, triggering Ni cations segregation from the host while maintaining structural stability via supplement of Fe guest cations. The FeNi alloy nanoparticles decorated cathode showed a current density of 1.49 A cm−2at 800 °C and 1.6 V for CO2electrolysis, demonstrating over 62.0 % improvement compared to the primitive PSCN cathode. Experimental studies and density functional theory calculations revealed that the activity originated from the unique ability to adsorb and activate CO2at the metal/perovskite interfaces. This cation supplement strategy may expand the frontiers in the evolution of exsolution on perovskite catalysts for CO2utilization and other heterogeneous catalytic reactions.

CO2electrolysis in solid oxide electrolysis cells (SOECs) is restricted by sluggish oxygen evolution reaction (OER) kinetics. Optimizing the electronic structure of anode material is an efficient strategy to improve OER activity and stability. Herein, the electronic structures of CaxSr1-xCo0.7Fe0.3O3-δ(x = 0, 0.5, 1) anodes are modified by A-site-induced structural transformation. Physiochemical characterizations and density functional theory calculations reveal that the crystalline structural transformation from orthorhombic brownmillerite CaCo0.7Fe0.3O3-δto tetragonal perovskite SrCo0.7Fe0.3O3-δlifts up the O 2p-band center to the Fermi level, which strengthens the M 3d-O 2porbitals hybridization and increases the oxygen vacancy concentration, oxygen ion migration capacity, and electrical conductivity. At 800°C, SOEC with the SrCo0.7Fe0.3O3-δanode achieves the highest current density of 2.03 A cm−2at 1.6 V with a stable operation of 487 h at 1.2 V, superior to the benchmark La0.6Sr0.4Co0.2Fe0.8O3-δ, Ba0.5Sr0.5Co0.8Fe0.2O3-δand PrBaCo2O6-δanodes.

MOF-based core-shell structures with high surface area, abundant active sites, and broad absorption bands are viable alternatives to traditional single-component photocatalysts. In this report, we describe the design and construction of delicate Ag nanowires@NH2-UiO-66 with a core-shell structure for use as photocatalysts in imine synthesis under light. The optimized composites exhibited 80% imine production, which was higher than both MOF and Ag NWs. The significant improvement in photocatalytic activity under light may be attributed to the plasmonic effect of silver nanowires and their core-shell structure, which promotes the separation of electron-hole pairs. Moreover, the photocatalytic activity of the core-shell nanostructure may provide valuable insight into the design and construction of MOF-based composite photocatalysts for oxidative coupling of amines.

An energy-effective polyaniline coated graphite felt (PANI@GF) composite cathode for the electro-Fenton (E-Fenton) process was synthesized through an electro-polymerization method. The electrocatalytic activity of the cathode for the 2e−ORR process was investigated and dimethyl phthalate (DMP) was used as a model substrate to evaluate its performance in the E-Fenton process. The as-prepared PANI@GF composite possessed a three-dimensional porous structure, which is favorable for O2diffusion, while the large amount of N atoms in the conductive polyaniline (PANI) enhanced 2e−ORR reactivity. The DMP degradation of the E-Fenton system using PANI@GF was significantly enhanced owing to the improvement in ORR performance. The apparent kinetic constant for DMP degradation was 0.0753 min−1, five times larger than that of GF. The optimal carbonization temperature and polymerization time for the preparation of the PANI@GF composite cathode was found to be 900 °C and 1 h, respectively. Measurement conditions are a crucial factor for proper evaluation of cathode electrocatalytic performance. Accordingly, the O2flow rate, Fe2+concentration, and pH for DMP degradation were optimized at 0.4 L/min, 1.0 mmol/L, and 3.0, respectively. These results indicate that the present PANI@GF composite cathode is energy-effective and promising for potential use as an E-Fenton system cathode for the removal of organic pollutants in wastewater.

FRESHFIELDS BRUCKHAUS DERINGER 11/F Two Exchange Square Central, Hong Kong T: 852 2846 3400 F: 852 2810 6192 Website: www.freshfields.com The recent toxic spill into the Songhua River has thrust [...]

The key rate-limiting step of methane production by dry anaerobic fermentation with straw as main materials is acidication phase, and carbon nitrogen ratio (mC/mN) is major factor in affecting microbial fermentation performance. In this study, a batch test was carried out to investigate the effect of different mC/mN ratio on acidogenic fermentation performance by means of a new medium-temperature complex microbial community LZF-12 with high efficent lignocellulosic degration, which straw and peptone were sole carbon and nitrogen respectively in reaction system. The results showed that flora growth of LZF-12 increased graduately along with the dicrease of mC/mN ratio, especially that the mC/mN ratio reached 5.0, the growth rate of microbial flora was obviously better than that of other mC/mN ratio, and pH revealed similar change trend that finial pH was between 6-7 along with different mC/mN ratio. Analysis of straw weightlessness revealed that substrate degradation rate achieved above 70% at the condition of diffenent mC/mN ratio, and fermentation was typically acetate-type, which main liquid end production were volatile fatty acid (VFA) comprising 90% acetate, butyate and a small amount of ethanol and propionate. This work presents important analysis of fermentation property together with carbon nitrogen scale applicable for biodegradation process of cellulose by complex microbial community LZF-12, and is benefical to technological optimization of dry anaerobic straw fermentation.

No Abstract

No Abstract

In the electrochemical CO2reduction reaction (CO2RR), single atom catalysts (SACs) supported on carbon materials have exhibited high activity and selectivity. However, the carbon supports are mainly graphene and carbon nanotubes, which are composed of sp2-hybridized carbon. Graphdiyne with sp-hybridization has been investigated as a promising carbon material for various catalytic reactions. In this study, the effect of sp-hybridization on graphdiyne was investigated using density functional theoretical (DFT) calculations for the CO2RR reactivity of Mn, Fe, Co, Ni, Cu, and Zn SACs supported on graphdiyne (M–graphdiyne). Among them, Co–graphdiyne exhibits a high activity and selectivity for CH3OH product, with remarkably low free energy barrier of 0.31 eV, which is superior to SACs supported on graphene with sp2-hybridization. The d-band center and atomic number of the metal atom, and the charge redistribution on sp-hybridization exert significant influence to the energy of intermediates, which are key to understanding the activity and selectivity of SACs in CO2RR.

Cubic perovskite oxides usually suffer from delamination and Sr2+segregation for catalyzing oxygen evolution reaction (OER) at the anodes of solid oxide electrolysis cells (SOECs). It is crucial to develop alternative and efficient anode materials for SOECs. Herein, a series of novel Y0.95-xSrxCo0.3Fe0.7O3-δ(YSCF-x) orthorhombic perovskite oxides in the Pnma (62) space group are synthesized as anode materials of SOECs. Physicochemical characterizations and density functional theory calculations reveal that the partial substitution of Y3+by Sr2+increases the oxygen vacancy concentration and mobility as well as improves the electrical conductivity, which contributes to the excellent OER activity of YSCF-x. At 800 °C, the current density of SOEC with YSCF-0.05-Ce0.8Sm0.2O2-δanode can reach 1.32 A cm−2at 1.6 V, about twice that of SOEC with Y0.95Co0.3Fe0.7O3-δ-Ce0.8Sm0.2O2-δanode. This work paves a new avenue for the design of advanced anode materials of SOECs.

For Abstract see ChemInform Abstract in Full Text.