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[Display omitted] The solid solutions of Zr 1– x Sc x O 2– δ (0 < x ≤ 0.1) were prepared using a precursor technology, and their structural, optical, and photocatalytic characteristics were studied. Mixed formates synthesized by an original method were used as precursors. Scandium favored the formation of ZrO 2 in tetragonal syngony and increased its photoactivity in the UV range. [ABSTRACT FROM AUTHOR]

• V Bi ″ ′ V 0 · · · V bi ″ ′ vacancy associates in BiOBr precursors converted into dual V Bi 0 vacancy sites during CO 2 ER. • Dual V Bi 0 vacancy associates enhance the CO 2 ER activity and selectivity of Bi° catalysts. • Bi VNS achieves a remarkable j HCOO −up to 755 mA/cm2 in a flow cell. • Dual V Bi 0 vacancy associates regulate the adsorption strength of the *OCHO intermediate. The electrocatalytic reduction of carbon dioxide (CO 2 ER) into formate presents a compelling solution for mitigating dependence on fossil energy and green utilization of CO 2. Bismuth (Bi) has been gaining recognition as a promising catalyst material for the CO 2 ER to formate. The performance of Bi catalysts (named as Bi-V) can be significantly improved when they possess single metal atom vacancy. However, creating larger-sized metal atom vacancies within Bi catalysts remains a significant challenge. In this work, Bi nanosheets with dual V Bi 0 vacancy (Bi-DV) were synthesized utilizing in situ electrochemical transformation, using BiOBr nanosheets with triple vacancy associates (V Bi ″ ′ V O · · V Bi ″ ′ , V Bi ″ ′ and V O · · denote the Bi3+ and O2− vacancy, respectively) as a template. The obtained Bi-DV achieved higher CO 2 ER activity than Bi-V, showing Faradaic efficiency for formate production of >92% from -0.9 to -1.2 V RHE in an H-type cell, and the partial current density of formate reached up to 755 mA/cm2 in a flow cell. The comprehensive characterizations coupled with density functional theory calculations demonstrate that the dual V Bi 0 vacancy on the surface of Bi-DV expedite the reaction kinetics toward CO 2 ER, by reducing the thermodynamic barrier of *OCHO intermediate formation. This research provides critical insights into the potential of large atom vacancies to enhance electrocatalysis performance. [Display omitted] [ABSTRACT FROM AUTHOR]

The emerging integrated CO 2 capture and utilization (ICCU) potentially contributes to net zero emissions with low cost and high efficiency. The catalytic performance in ICCU process is highly restricted by the equilibriums of carbonate decomposition and dry reforming of methane (DRM). Here, we engineer a unique yolk-shell dual functional nanoreactor construction to improve the catalytic performance via confined catalysis. By tailoring the carbonates decomposition kinetics and confining the CO 2 diffusion path, ∼92% CO 2 conversion is achieved over (Ni/Ca)@Si and shows no distinct activity loss in 10 cycles at 650 °C. The formed Ca 2 SiO 4 shells restrain the sintering of CaO yolks by acting as physical barriers, and stabilize the Ni particle size. It is also confirmed on in situ DRIFTS that the integrated DRM might occur via carbonyls, formates and CHO intermediates, in which formates species are highly dependent on Ni-carbonates interfaces. [Display omitted] • Ni-functionalized Ca@Si yolk-shell nanoreactors achieves effective CO 2 capture and in situ methane dry reforming. • Yolk-shell structure promote the catalytic performance by confined catalysis. • Ca 2 SiO 4 shell stabilizes both the CaO yolk and catalytic sites. • Formates are dependent on Ni-carbonates interfaces. [ABSTRACT FROM AUTHOR]

• Synthesis and Performance of Novel Ti-MOF: The study successfully designed and synthesized a novel titanium-based Metal-Organic Framework (Ti-MOF) using a covalent strategy. This new material exhibits excellent performance under visible light catalysis, bearing significant implications for catalysis. • Outstanding Photocatalytic Performance: The research extensively investigates Ti-MOF's performance in photocatalytic CO 2 reduction to formate ions under visible light. The results showcase Ti-MOF exceptional catalytic capabilities, with a formate production rate of 46.0 μmol g−1 h−1, six times higher than the control MOF-902. • Distinct Band Structure: The study underscores Ti-MOF's band structure as a crucial factor in its remarkable performance. The narrow band gap and pronounced negative shift in the conduction band play a pivotal role in Ti-MOF efficient reduction performance. • Alignment with Journal Themes: This study will provide new insights in heterogeneous porous photocatalysts, catalysis chemistry, and materials science. Ti based Metal-organic frameworks materials, with their high surface area, visible light responsiveness, and abundant catalytic active sites, have emerged as efficient photocatalysts. However, the number of reports on titanium-based MOFs is limited, mainly due to the challenges associated with their synthesis. In this study, based on the covalent strategy of imine condensation, a novel Ti-MOF was designed and synthesized by rational selection of aldehyde ligands. The photocatalytic CO 2 reduction performance of the Ti-MOF was evaluated, and it exhibited a remarkable generation rate of formate ions at 46.0 μmol g−1 h−1, which is more than 6 times higher than that of MOF-902 constructed with the same titanium cluster. The rational selection of aldehyde ligands resulted in a relatively superior band structure for the Ti-MOF, characterized by a narrowed bandgap and a significantly negative shift of the conduction band, leading to enhanced photocatalytic ability. [Display omitted] [ABSTRACT FROM AUTHOR]

• Catalytic activity of Ni depends appreciably on the nature of the support. • 5%Ni/TiO 2 exhibits optimum performance for the selective methanation of CO. • Catalytic performance of 5%Ni/TiO 2 is improved by decreasing space velocity. • The operating temperature window can be expanded by mild reduction of 5%Ni/TiO 2. • Mild reduction suppresses the formation of reactive formates for CO 2 methanation. The catalytic activity of supported Ni (5 wt.%) catalysts for the selective methanation of CO in the presence of excess CO 2 has been investigated with respect to the nature of the support, operating and pretreatment conditions employed. It has been found that catalytic activity of Ni depends appreciably on the nature of the support. The specific reaction rate (TOF) for CO hydrogenation increases by 2 order of magnitude in the order of Ni/CeO 2 < Ni/Al 2 O 3 < Ni/YSZ < Ni/ZrO 2 < Ni/TiO 2. The effect of the nature of the support is less pronounced for the CO 2 hydrogenation with specific activity being one order of magnitude higher when Ni is supported on ZrO 2 compared to CeO 2 , whereas Ni/TiO 2 , Ni/YSZ and Ni/Al 2 O 3 exhibit intermediate performance. Results provide evidences that the performance of 5%Ni/TiO 2 catalysts can be improved by optimizing operating and/or pretreatment conditions. In particular, catalytic activity for both CO and CO 2 hydrogenation reactions can be increased with decreasing the gas hourly space velocity. The improvement is lower for the CO 2 methanation, thus, expanding the temperature window for the selective methanation of CO. It has been found that increase of the in situ reduction temperature or time prior to catalytic performance tests results in an increase of the CO 2 methanation reaction rate, whereas CO hydrogenation remains practically unaffected. DRIFT results showed that the relative population of reactive surface species (Ni carbonyls) for the CO methanation reaction are not affected by varying pretreatment conditions. However, population of reactive surface species (formates) for the CO 2 methanation increases under prolonged reduction of catalyst. Therefore, mild in situ reduction conditions of Ni/TiO 2 catalyst are required in order the selective methanation of CO to be operable in a wide temperature range. [ABSTRACT FROM AUTHOR]

• A cobalt/alumina catalyst was modified with tin. • The Sn-modified samples were less active for methanol production. • The methanol rate of formation correlated with H 2 adsorption capacity. • Surface formates on Sn-modified samples showed a markedly lower reactivity. Hydrocarbons are the main reaction products of syngas conversion over cobalt-based catalysts. Methanol is also produced as a minor by-product and has been proposed to be produced via a specific reaction pathway involving formates species located at the interface with the support. The poisoning of a Co/alumina catalyst with Sn was studied here and showed to induce a strong decline in methanol production, similar to that of hydrocarbons. The addition of Sn did not prevent the formation of formates as observed by operando diffuse reflectance FT-IR spectroscopy. However, the reactivity of formates was markedly lowered in the presence of Sn. We propose that these observations have two possible origins. Firstly, Sn addition reduced significantly the H 2 adsorption capacity of the Sn-modified samples. Hydrogen, which is required for the hydrogenation of formates to methanol, is probably activated on the cobalt metal particles, some sites of which were strongly poisoned by Sn. Secondly, Sn addition could also have specifically poisoned interfacial sites, where the most reactive formates are present. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ni/CeO 2 -SiO 2 -P and -C with different structures were used for DRM. • The interaction model between Ni and CeO 2 affected the catalytic performance. • Ni/CeO 2 -SiO 2 -P exhibited superior low-temperature activity and H 2 /CO ratio. • More reactive oxygen species on Ni/CeO 2 -SiO 2 -P improved the stability. • Formate species were observed on Ni/CeO 2 -SiO 2 -P. Abstract Manipulating interfacial structure and interaction between metal and supports is important for many heterogenous catalysts with the aim at achieving high and stable activity and selectivity. In this work, two kinds of Ni/CeO 2 -SiO 2 catalysts are fabricated and designed, including CeO 2 close contact with Ni nanoparticles (Ni/CeO 2 -SiO 2 -P) or CeO 2 away from Ni nanoparticles (Ni/CeO 2 -SiO 2 -C) for dry reforming of methane. Ni/CeO 2 -SiO 2 -P exhibits superior low-temperature activity and H 2 /CO ratio compared with Ni/CeO 2 -SiO 2 -C. CO 2 and CH 4 conversions on the former (87.3% and 78.5%) are higher than those of the later (80.5% and 67.8%) at 700 °C. Meanwhile, Ni/CeO 2 -SiO 2 -P is stable in the long-term study whereas Ni/CeO 2 -SiO 2 -C presents poor stability and the activity dramatically decreases in 10 h. The improved performance and stability on Ni/CeO 2 -SiO 2 -P originates from more reactive oxygen species and more accessible sites for the formate species on the metal–support interface. The reaction order and activation energy of both catalysts are also calculated in the kinetic studies. This work opens up new possibilities for exploring the effect of metal–support on designing highly efficient heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

Abstract Liquid-liquid equilibrium (LLE) data for poly (ethylene glycol) (PEG) of different molecular weights (600, 1500, 3000, 6000) + sodium formate (NaCHO 2), potassium formate (KCHO 2) + water at different temperatures (298.15 and 308.15 K) and for PEG (1500) + sodium formate + water at different pH values (8.05, 9.06, 10.92), were determined experimentally. The tie lines and plait point are reported at different PEG molecular weight, pH, temperature and type of cation. Furthermore, the effect of those parameters on binodal curve, tie-line length (TLL) and slope of tie line (STL) are discussed in detail by comparing the results to that of literature data. The effective excluded volume (EEV) values obtained from the LLE data were used to study the effect of the parameters on the binodal curves. The phase composition and the tie-lines' ends were obtained by measuring the density (ρ) and refractive index ( n D ). Furthermore, the binodal curves and the tie-line compositions were well-fitted by using some semi empirical equations. Highlights • ATPS were prepared combining PEG (600, 1500, 3000, 6000) with NaCHO 2 , KCHO 2. • The heterogeneous region increases with temperature and PEG Mw. • The effect of pH on the size of the heterogeneous region can be neglected. • The EEV increases with the rise on pH, temperatures, and PEG Mw. • The effect of Na+ is more effective in inducing phase separation compared to K+. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Formate-assisted pyrolysis is an effective way for the kraft lignin decomposition. • Monophenols and polyphenols were the main products of kraft lignin with formates. • Nickel formate showed highest selectivity of polyphenols and hydrocarbons. • Nickel formate showed the synergetic effect of hydrogen donor and nickel catalysis. Abstract The effect of sodium formate (SF), calcium formate (CF) and nickel formate (NF) as additives on analytical pyrolysis performance of kraft lignin was conducted. The results showed that these formates promoted the releasing of volatiles, leading to the rapid degradation of kraft lignin. High relative content of monophenols (53.77%), especially of guaiacol (23.65%), were achieved from the pyrolysis of pure lignin. The relative content of guaiacol was dramatically decreased after the adding of formates in kraft lignin. The relative content of polyphenols such as 3-methylcatechol and 4-methylcatechol reached to 16.97%, 16.23% and 21.95% with the formates of SF, CF and NF, respectively. The NF showed the highest selectivity of polyphenols and hydrocarbons. The increase of polyphenols and hydrocarbons from NF was the synergetic effect of the hydrogen radical reaction from the formic functional groups under the catalysis of Ni and/or NiO produced from the NF pyrolysis process. [ABSTRACT FROM AUTHOR]

Abstract Temperature dependences of the frequencies for the Raman modes of ν (NH 2), ν s (CH 3), ν 1 (HCOO−), ν S (CNN) and IR mode of ρ (NH 2) are calculated in particular, for MHyMn close to the phase transition temperature (T C = 220 K) in the family of compounds CH 3 NH 2 NH 2 M(HCOO) 3 , MHyM with M = Mn, Mg, Fe and Zn. By assuming Raman and infrared frequency as an order parameter, this calculation is performed from the molecular field theory by using the experimental data from the literature. We also calculate the damping constant (FWHM) from the order parameter (Raman and IR frequency of those modes) by using the pseudospin (MHy+ cations)-phonon coupled model (PS) and the energy-fluctuation model (EF) for methylhydrazinium metal formate frameworks. Expressions of the damping constant from both models are fitted to the observed FWHM data for the Raman and infrared modes studied for these metal formates. Our results show that the anomalous behaviour of the Raman and IR frequencies of those modes, except the ν S (CH 3) Raman mode which are associated with the phase transition can be described adequately by the molecular field theory in MHyM, as observed experimentally. Also, the damping constant calculated from the PS and EF models can explain the observed FWHM of those Raman and IR modes studied in methylhydrazinium metal formate frameworks. Highlights • Raman and IR frequencies are calculated from the molecular field theory for MHyM. • FWHM of those Raman and IR modes are calculated from the PS and EF models for MHyM. • Experimental data from the literature are used for the modes of MHyM. • Molecular field theory (frequency), PS and EF models (FWHM) are applicable to the MHyM. [ABSTRACT FROM AUTHOR]

Abstract The disadvantage of anion ionomer that possesses low hydroxide conductivity, and thermal and chemical instability hinders the development of the high-performance anion-exchange membrane direct liquid fuel cells. Instead of adding additional base and synthesizing high-conductivity ionomer material, by gaining insight into species transports, herein, we propose an anion-ionomer-free anion-exchange membrane direct formate fuel cell (AEM DFFC). Experimental result reveals that this conceptual anion-ionomer-free AEM DFFC can operate stably within a 6-h constant-current discharge at 10 mA cm−2, mainly because formate hydrolysis renders a high OH− conductivity. It was also found that the anion-ionomer-free AEM DFFC yields a peak power density as high as 41 mW cm−2 at 40 °C, 40% higher than that of the conventional quaternary ammonia polysulfone anion-ionomer AEM DFFC. This can be attributed to the fact that the OH−-containing formate solution facilitates the mass and charge transports, thereby enlarging the triple-phase boundary for both anodic formate oxidation reaction and cathodic oxygen reduction reaction. Graphical abstract Image 1 Highlights • An anion-ionomer-free AEM direct formate fuel cell was proposed. • A stable 6-h constant-current discharge was achieved at 10 mA cm−2. • Formate hydrolysis renders the mass and charge transport media. [ABSTRACT FROM AUTHOR]

Highlights • HILIC-MS/MS was used for the determination of 16 coccidiostats in muscle and eggs. • Good accuracy and remarkably low LOQs were achieved in very short analysis time. • 82 meat & egg samples were analysed through the Greek National Residue Control Plan. • New data were obtained regarding the occurrence of coccidiostat residues in Greece. Abstract A simple, sensitive and efficient confirmatory method was developed and validated for the determination of 16 coccidiostats in animal tissues and eggs using hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC-MS/MS). The sample preparation consisted of a solid-liquid extraction with ACN and dispersive SPE cleanup with MgSO 4 and C 18. Analysis was realized in an Acquity BEH HILIC silica column, in SRM mode. Both positive and negative ionization was performed, using polarity switching. Isocratic elution was used with a mobile phase of ACN: aqueous ammonium formate 1 mM with 0.1% formic acid (80:20, v/v). Method validation was performed in eggs, poultry, bovine, ovine, porcine and rabbit tissue and exceptionally low LODs were achieved, varying from 0.004 μg kg−1 (decoquinate in porcine tissue) to 0.560 μg kg−1 (halofuginone in eggs). The developed methodology was applied in 82 muscle and egg samples through the Greek National Residue Control Plan for coccidiostats. [ABSTRACT FROM AUTHOR]

Abstract Practical preparations of dichloromethyl alkyl ethers are described, based on the reaction of alkyl formates with oxalyl chloride in the presence of N -methylformanilide. The method involves a simple procedure that does not require the use of harmful reagents. Dichloromethyl propyl and dichloromethyl butyl ethers represent secure synthetic equivalents to dichloromethyl methyl ether. Formylations of both electron-deficient and electron-rich aromatics with these dichloromethyl alkyl ethers in the presence of AlCl 3 , FeCl 3 , or TiCl 4 have been systematically investigated. A plausible mechanism of formylation is discussed. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Highlights • Formate salts were explored as new additives in the CaO-activated fly ash system. • The effect of formate on strength was dependent on the formate salt's cation type. • The use of Ca(HCOO) 2 was significantly effective in improving strength. • The use of Ca(HCOO) 2 notably increased C-S-H and reduced overall pore sizes. Abstract This study investigated whether three formate salt additives (Ca(HCOO) 2 , NaHCOO, and KHCOO) could improve the strength of a CaO-activated fly ash (FA) system. Various tests were conducted to verify the effects of the formate salts including compressive strength, X-ray diffraction (XRD), thermogravimetric (TG) analysis, solid-state 27Al magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy, and mercury intrusion porosimetry (MIP). The results showed that the addition of Ca(HCOO) 2 significantly strengthened the FA binder system by (1) substantially increasing C-S-H formation and (2) measurably reducing overall pore size. However, adding NaHCOO or KHCOO was much less advantageous to strength improvement because although helpful in dissolving FA, the high pH environment caused by their reaction with CaO inhibited further dissolution of CaO, which was the main activator used in this study. [ABSTRACT FROM AUTHOR]

Abstract The formic acid oxidation reaction has been studied in concentrated perchloric acid solutions (up to 9.14 M (60%)) on the Pt (111) surface to explore the relationships between interfacial properties and kinetics. It is found that, as the concentration of perchloric acid in the supporting electrolyte increases, the current markedly decreases, making it possible to detect adsorbed formate on the surface by voltammetric methods. With the aid of DFT calculations, it is shown that the diminution in current is the result of two opposing factors: the reduction in the concentration of free formate in solution and electrode charge effects which encourage the adsorption of formate in a particular configuration. Additionally, the electrochemical behavior under highly acidic conditions suggests the formation of clathrate structures and emphasizes the relevance of the water structure effect in electrode adsorption processes. Highlights • Oxidation currents for formic acid diminish as the pH is made more acidic. • The net current is the result of two opposing effects: surface charge and concentration of free formate. • In highly acidic conditions clathrates are formed. [ABSTRACT FROM AUTHOR]

Highlights • Potassium and calcium brines extend the shear-thinning behaviour of xanthan. • Thermorheological behaviour of xanthan depends on the type of salt in the brine. • Formate brine shifts the order/disorder transition of xanthan to high temperature. Abstract Xanthan gum solutions are used in the oil industry for flooding, drilling and completion operations. The stabilization of the structure of xanthan gum solutions in presence of salts increases the value of both the order-disorder transition temperature and the gel strength. This effect is very important in order to design drilling and completion fluids since not only density and viscosity of the fluid can be improved by increasing the concentration of salts but also the range of temperature where the solution shows viscoelastic behaviour can be extended. This paper presents results from a study on the rheological behaviour of xanthan gum solutions in different saturated brines. Chloride and formate potassium brines not only increase the viscosity of the solution but also extend the shear thinning behaviour to temperatures near 200 °C, maintaining a simple relaxation mechanism over the whole range of temperature where the ordered conformation dominates the rheological behaviour. [ABSTRACT FROM AUTHOR]

In this work, we present the development of a method for the determination of acetate and formate in vegetable oils by ion chromatography with conductometric detection following their extraction from samples using a diluted KOH solution. The extraction procedure was optimized using a multivariate approach. The application of a 2 4 full factorial design showed that the mass of sample, extraction time, and KOH concentration presented significant influence on the extraction of both acetate and formate, whereas the temperature presented little influence on the process. As a result, we set the extraction temperature at 22 °C and performed the multivariate optimization of the other variables using a Doehlert design. The optimum conditions were: 4.8 g of sample, 8 mmol L −1 KOH solution and 19 min extraction time. Six samples of vegetable oils (soybean, corn, canola, sunflower and olive) were analyzed and recovery tests provided recovery percentages in the range of 82–118%. [ABSTRACT FROM AUTHOR]

Highlights • Terpinyl formate, safety assessment based on RIFM's criteria. • Safety assessment based on 7 human health endpoints plus environmental. • All endpoints were cleared using target data, read-across, and/or TTC. [ABSTRACT FROM AUTHOR]

Highlights • 3a,7-Methano-3aH-cyclopentacycloocten-3-ol, decahydro-1,1,7-trimethyl-, formate, safety assessment based on RIFM's criteria. • Safety assessment based on 7 human health endpoints plus environmental. • All endpoints were cleared using target data, read-across, and/or TTC. [ABSTRACT FROM AUTHOR]

Highlights • Octyl formate, safety assessment based on RIFM's criteria. • Safety assessment based on 7 human health endpoints plus environmental. • All endpoints were cleared using target data, read-across, and/or TTC. [ABSTRACT FROM AUTHOR]

Highlights • Hexyl formate, safety assessment based on RIFM's criteria. • Safety assessment based on 7 human health endpoints plus environmental. • All endpoints were cleared using target data, read-across, and/or TTC. [ABSTRACT FROM AUTHOR]

• Three novel FDHs with higher catalytic activity toward sodium bicarbonate including Fm FDH, Ks FDH and Ss FDH were obtained. • Ss FDH has greater potential in CO 2 reduction. • Catalytic mechanism of reducing CO 2 to formate was explained using bioinformatic and computational biochemical methods. Formate dehydrogenase (FDH, EC 1.17.1.9) belongs to the class of d -2‑hydroxy acid dehydrogenases and is widely found in bacteria, archaea, yeast, fungi, plants and vertebrates. In recent years, the inverse reduction reaction of carbon dioxide to formate catalyzed by FDH has attracted widespread interest. However, the low catalytic activity has greatly limited its industrial application. In this work, three novel FDHs including Fm FDH, Ks FDH and Ss FDH, were discovered. Ss FDH showed relatively high catalytic activity toward CO 2 conversion. The enzymological properties of the enzymes were characterized, and the catalytic mechanism of reducing CO 2 to formate was investigated using bioinformatic and computational biochemical tools. The results of this work provide new insights into the function, structure and application of FDH in reducing CO 2 to formate. [Display omitted] [ABSTRACT FROM AUTHOR]

An efficient heterogeneous photocatalytic system for high-purity hydrogen evolution from formate or aldehyde-water solution were developed using IrCp*Cl (Cp* = η 5 -pentamethylcyclopentadienyl) complex anchored onto the robust bipyridine-based organosilica nanotubes as a solid catalyst. This system can be conducted at the room temperature with a visible light (λ > 420 nm) illumination. The heterogeneous molecular photocatalyst displayed much improved catalytic activity and recyclability compared to the analogous homogeneous catalyst, benefiting from the isolated photoactive sites as well as the efficient transport of substrates and products in the nanotube channels. A detailed characterization for the solid catalyst after the reactions by UV/vis, XPS and 13 C CP MAS NMR testified the molecular nature of the active species. This work provides an easy method to construct the heterogeneous molecular photocatalysts for the high-purity hydrogen generation under mild conditions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • An integrated method of photosynthesis and geochemistry for CO 2 reduction is proposed. • The biomass-derivative hexanehexol acts as a reductant under hydrothermal conditions. • An about 80% yield of formate is achieved at 300 °C for 1 h. • This study should provide useful information for CO 2 conversion with real biomass. Abstract In the nature, CO 2 and water are converted into biomass or organics via photosynthesis and geochemistry, respectively. The use of renewable biomass for CO 2 reduction under hydrothermal conditions means the integration of photosynthesis and geochemistry for CO 2 reduction, and then a rapid and highly efficient CO 2 reduction can be expected. Here, we report a hydrothermal reduction of CO 2 /NaHCO 3 by using biomass-derivative hexanehexol, which has the most similar structure to carbohydrate biomass, as a preliminary work for CO 2 reduction with real biomass. We show that NaHCO 3 can be reduced into formate, and an about 80% yield of formate based on the initial hexanehexol was achieved at 300 °C for 1 h. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Using electrochemical reduction to convert CO 2 into useful small molecule fuels represents a value-added approach to the simultaneous generation of alternative fuels and environmental remediation of carbon emissions from the continued use of conventional fuels. Here, we report a novel flow cell design for CO 2 electroreduction. The alkaline ion-exchange membranes are used to separate anolyte from aqueous catholyte, and the commercial Sn particles are deposited over a carbon support, which serves as the cathode. Various influence factors on the electrochemical reduction of gaseous CO 2 into fuel are investigated, including a selection of different alkaline-exchange membranes, time duration of the electrolysis, current density and flow rate of electrolyte on the produced formate as a target fuel. Three alkaline membranes (A901, FAD and Yichen) and an acidic membrane (Naffion 117) are used. The maximum Faradaic Efficiencies (FE) of formate formation are 82.8% (Yichen), 79.2% (A901) and 90.1% (FAD), which are comparable to and even higher than that of Nafion 117 membrane (89.2%). In particular, the FAD alkaline membrane showed an applicable prospect with cell voltage of 2.85 V, lower than when using Nafion 117 membrane. We also successfully achieve the formate production rate over 1.47 mmol m−2 s−1 at a working current density of 50 mA cm−2 over 60 min continuous' operation, allowing the formate concentration up to 1.9 g L−1. These encouraging results reveal that different ion-exchange membranes have obvious impact on the electrochemical reduction of carbon dioxide (ERC). [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is a globally prevalent parasitic protist. It is well-known for its ability to infect almost all nucleated vertebrate cells, which is reflected by its unique metabolic architecture. Its fast-growing tachyzoite stage catabolizes glucose via glycolysis to yield L-lactate as a major by-product that must be exported from the cell to prevent toxicity; the underlying mechanism remains to be elucidated, however. Herein, we report three formate--nitrite transporter (FNT)--type monocarboxylate/ proton symporters located in the plasma membrane of the T. gondii tachyzoite stage. We observed that all three proteins transport both L-lactate and formate in a pH-dependent manner and are inhibited by 2-hydroxy-chromanones (a class of small synthetic molecules).Wealso show that these compounds pharmacologically inhibit T. gondii growth. Using a chemical biology approach, we identified the critical residues in the substrateselectivity region of the parasite transporters that determine differential specificity and sensitivity toward both substrates and inhibitors. Our findings further indicate that substrate specificity in FNT family proteins from T. gondii has evolved such that a functional repurposing of prokaryotic-type transporters helps fulfill a critical metabolic role in a clinically important parasitic protist. In summary, we have identified and characterized the lactate transporters of T. gondii and have shown that compounds blocking the FNTs in this parasite can inhibit its growth, suggesting that these transporters could have utility as potential drug targets. [ABSTRACT FROM AUTHOR]

Dicubane-like 3d-4f subunits are linked by azide or formate giving a series of 1D chains. The linkers of azide or formate have little influence on the structure of the M 2 Ln 2 subunits. Magnetic study indicated that ferromagnetic interactions exist in the chains of those complexes. At low temperature all the involved cobalt complexes exhibit slow magnetic relaxation. [ABSTRACT FROM AUTHOR]

Abstract Crystallinity and morphology of perovskite absorber layers are important factors for influencing on the performance and stability of perovskite solar cells. Here, a perovskite-like metal formate (PLMF) material is firstly introduced as the scaffold into the perovskite precursor solution to improve the quality of perovskite films by effectively controlling the crystallization process in the course of the perovskite growth. The results show that the perovskite films with PLMF exhibit well-organized crystallinity and compact morphology, and therefore decreased grain boundaries which will notably reduce the electron-hole recombination and the defect points exposed to humidity. Finally, the photoelectricity properties have been significantly improved. The device with 3 mg ml−1 PLMF achieves a power conversion efficiency of 19.17% with less hysteresis under AM 1.5G solar illumination, which shows a 16.53% increase than the pristine one (a power conversion efficiency of 16.45%). Importantly, the device with 3 mg ml−1 PLMF displays excellent stability compared to pristine device under 40 ± 5% and 70 ± 5% relative humidity (RH) in the dark, maintaining about 85% and 60% of the original efficiency after about 1000 h at room temperature, respectively. This work offers a potential way by employing scaffold additive to improve the performance and stability of perovskite solar cells. Graphical abstract Image 1 Highlights • PLMF was firstly introduced into the PSCs as a new-type scaffold additive. • High-quality perovskite films with fewer grain boundaries can be achieved. • The PCE was boosted from 16.45% to 19.17% by adding 3 mg ml−1 PLMF. • The devices with PLMF showed significantly improved humidity stability. [ABSTRACT FROM AUTHOR]

l -Phenylalanine l -Phenylalaninium Formate (LPPF) is an organic nonlinear optical crystal with molecular formula C 9 H 11 NO 2 ·C 9 H 12 NO 2 + ·CHO 2 − , was grown by solution growth, slow evaporation method. Single crystal XRD reveals that the title compound crystallizes in monoclinic system with the space group P2 1. The presence of functional groups was identified by FT-IR spectrum. UV–visible spectrum analysis shows that the crystal exhibits good optical transparency with a minimum cut-off wavelength of 200 nm. Refractive index of the crystal was measured as 1.6408 by using prism coupling technique. The Dielectric constant and dielectric loss were studied as a function of frequency at different temperatures and also activation energies were measured at different frequencies. The melting point of LPPF was found as 276.37 °C by TG-DSC analysis. Second order NLO efficiency was estimated by Kurtz Perry Powder technique. Third order NLO properties like nonlinear absorption coefficient (β), nonlinear refractive index (n 2) and third order nonlinear susceptibilities (χ 3 ) were measured with femto second pulsed laser using Z Scan technique. From third order NLO studies it is noticed that the material exhibiting strong reverse saturable absorption which is an essential requirement for passive optical limiting application. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Coexistence of chiral and perovskite phases in [NH 2 NH 3 ][Mn(HCOO) 3 ](HyMn) metal-organic compound. • Dielectric two-power law, generalized Mittag-Leffler response of HyMn. • The presence of polar nanoregions in HyMn suggesting the relaxor nature of the ferroelectricity. Abstract We report the synthesis, thermal and dielectric measurements of [NH 2 NH 3 ][Mn(HCOO) 3 ] (HyMn) compound. Above room temperature this polymeric material undergoes two phase transitions at ∼360 K and ∼298 K, as observed via DSC and BDS spectra. The first high temperature phase transition is associated with the paraelectric to ferroelectric transition of perovskite HyMn. The low temperature phase transition corresponds to the paraelectric to antiferroelectric transition of chiral HyMn. However, mechanisms hidden behind the observed two polymorphic phases are not completely clear yet. Dielectric spectroscopy measurements have revealed formation of clusters and superclusters as well as the relaxor-like behavior of this compound in wide temperature range resulting from both chiral and perovskite phases. Analysis of dielectric permittivity spectra obtained for the investigated material showed the generalized Mittag-Leffler two-power-law relaxation pattern that was interpreted by means the stochastic scenario of correlated-clusters. The proposed approach brought into light the presence of polar nanoregions in the material suggesting the relaxor nature of the existing ferroelectricity. [ABSTRACT FROM AUTHOR]

In this study we analyze the Electron Paramagnetic Resonance “EPR” response of lithium formate monohydrate “LFM” irradiated by photons and electrons using a linear accelerator. EPR measurements were performed one day after irradiation and regularly during six months of storage. Both dosimetric curves using peak to peak technique and double integration method showed linear behavior. The time dependence indicates good stability of free radicals produced on this material. The determined measurable threshold dose is 0.55 Gy. For used energies, LFM dosimeters are more sensitive to X-ray irradiation than to electrons. The deconvolution of the EPR signal of irradiated LFM using Levenberg-Marquardt (M-L) algorithm shows that this spectrum is constituting of three gaussian contributions. Each contribution has a linear evolution according to the irradiation dose, as well as an acceptable degree of stability during the storage period, approving the stability of all free radicals produced in LFM. All these characteristics confirm that LFM might be a promising dosimeter to be used in the ‘clinical’ dose range in radiotherapy. [ABSTRACT FROM AUTHOR]

A new high energy dense oxidizer (HEDO) 2,2,2-trinitroethyl-formate (TNEF) was prepared and characterized by nuclear magnetic resonance (NMR). A new propellant based on glycidyl azide polymer (GAP) and TNEF was prepared. Thermo-analytical study of TNEF in comparison with ammonium dinitramide (ADN) and their propellant formulations based on GAP were investigated. The decomposition gaseous products and the combustion characteristics of the propellants were determined by using thermodynamic code (EXPLO5_V6.03). Scanning electron microscope (SEM) technique was applied to clarify the crystal morphology of the oxidizers in addition to the homogeneity of the propellants ingredients. Impact and friction sensitivities of the oxidizers and the GAP binder were measured. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques were used to study the pyrolysis of the oxidizers as well as the prepared propellants. The decomposition kinetics were determined by Kissinger and Kissinger–Akahira–Sunose (KAS) methods The thermal degradation of ADN is faster than TNEF oxidizer. ADN and TNEF have melting temperatures at 95.5 and 127.1 °C and maximum decomposition temperature at 183.5 and 210.1 °C respectively. In addition, TNEF has activation energy in the range of 131–146 kJ mol −1 , while ADN has activation energy in the range of 114–117 kJ mol −1 . TNEF has specific impulse (250.1 s) higher than ADN (202.4 s). TNEF is a promising oxidizer to be used in composite solid rocket propellants. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Rh/TiO 2 catalyst realizes the complete removal of HCHO at ambient temperature. • The humidity significantly improves the activity, stability and specific rates. • Rh supplies sites for O 2 adsorption and TiO 2 for the transformation of HCHO to formates. • The CH 2 O oxidation goes through the reaction between formates and hydroxyls. Abstract Catalytic oxidation of formaldehyde (HCHO) to CO 2 and H 2 O under ambient condition is highly desired for purifying indoor air quality. In this work, it was found for the first time that TiO 2 supported subnanometer Rh catalyst exhibited a remarkable activity with complete removal of HCHO at room temperature. The humidity under ambient condition can significantly improve the activity, stability and specific rates but result in lower activation energy for the oxidation of HCHO on this catalyst. A combination of characterizations, such as H 2 temperature programmed reduction, adsorption microcalorimetry and in situ diffuse reflectance infrared Fourier transform spectroscopy, demonstrated the importance of Rh species for the dissociative adsorption of O 2 and the key role of water on the oxidation of HCHO. The O atoms facilitated the transformation of HCHO adsorbed on TiO 2 into intermediate of formates, while the presence of water led to the production of hydroxyl probably from the reaction with the adsorbed O species, which promoted the decomposition of formates to CO 2. This study can provide an important implication into the design and fabrication of more economic Rh-based catalysts for ambient HCHO oxidation. [ABSTRACT FROM AUTHOR]

A hydrophilic interaction liquid chromatography method with diode array detection (HILIC-DAD) was developed and validated for the simultaneous determination of impurities in extended-release fixed-dose combination tablets containing rosuvastatin and metformin in a ratio 1:100. The analytes were separated by hydrophilic interaction liquid chromatography using an XBridge®-HILIC analytical column under isocratic elution. The mobile phase was composed of ammonium formate at 150 mM containing 0.05% diethylamine (pH 8.5)/acetonitrile, 4/96 (v/v) and pumped at a flow rate of 0.5 mL min −1 . Method validation was performed according to ICH guidelines. The calibration curves for rosuvastatin, metformin and their seven impurities showed good linearity (r > 0.994) within the calibration ranges tested. The intra- and inter-day R.S.D. values were less than 4.5%, while the relative percentage error Er was less than 2.7% for all compounds. Accelerated stability studies performed under various stress conditions including hydrolysis, oxidation and heat proved the selectivity of the procedure. A run time of less than 25 min for each sample made it possible to analyze a large number of samples per day. The method is the first reported application of HILIC for the analysis of impurities in fixed-dose combination tablets containing rosuvastatin and metformin and it can be used for the quality control of these drugs. [ABSTRACT FROM AUTHOR]

Renewable biomass based levulinic acid was converted to 5-methyl-2-pyrrolidone in 94% yield by a Raney-Ni catalyzed process using ammonium formate in aqueous medium and heating at 180 °C for 3 h. The Raney-Ni could be reused for four catalytic cycles with about 10% loss in catalytic activity. In a similar reaction levulinic acid could be converted 1-substituted-5-methyl-2-pyrrolidones in 90–95% yield by using a mixture of formic acid and the corresponding primary amine. [ABSTRACT FROM AUTHOR]

In this article, we report a catalytic reduction of CO 2 to formate in the presence of metallic cobalt nanoparticles as an elegant heterogeneous catalyst. The aforementioned cobalt nanoparticles was prepared by the pyrolysis of impregnated cobalt precursor on cucurbit[6]uril (CB[6]). During the pyrolysis process, CB[6] framework transform to the nitrogen-rich graphitic carbon support in which cobalt nanoparticles were present in their metallic state. The synthesized catalyst was highly active for the catalytic hydrogenation of CO 2 with 1 M KOH solution at 120 °C by applying 1:1 partial pressure of pCO 2 /pH 2 to obtain a high TON of 82,265 in 24 h. Moreover, the influence of all the catalytic parameters was investigated with the reusability of the catalyst. In sort, the catalytic protocol shows excellent activity and robust nature for the CO 2 utilization reaction with economical/ abundant metal source, in aqueous media and with molecular hydrogen. [ABSTRACT FROM AUTHOR]

The discovery of sulphite in basic chromium sulphate, typically used as the source of Cr(III) ions in trivalent chromium electrolytes, sparked an investigation into the effects of this species on the reactions at a platinum electrode in a Cr(III)-formate electrolyte. The specific adsorption and oxidation-reduction reactions of sulphite were mapped using cyclic voltammetry and linked to competitive adsorption between sulphite, formic acid and the Cr(III)-formate complex. It was found that sulphite adsorption and reduction/oxidation dominates the cyclic voltammogrammetric response. Formic acid oxidation is completely inhibited as long as sulphite is present at the surface. A feasible way of removing any sulphite from a contaminated electrolyte is by applying a prolonged reductive current. [ABSTRACT FROM AUTHOR]

Background: Formate is produced in mitochondria via the catabolism of serine, glycine, dimethylglycine, and sarcosine. Formate produced by mitochondria may be incorporated into the cytosolic folate pool where it can be used for important biosynthetic reactions. Previous studies from our lab have shown that cobalamin deficiency results in increased plasma formate concentrations.Objective: Our goal was to determine the basis for elevated formate in vitamin B-12 deficiency.Methods: Male Sprague Dawley rats were randomly assigned to consume either a cobalamin-replete (50 μg cobalamin/kg diet) or -deficient (no added cobalamin) diet for 6 wk. Formate production was measured in vivo and in isolated liver mitochondria from a variety of one-carbon precursors. We also measured the oxidation of [3-14C]-l-serine to 14CO2 in isolated rat liver mitochondria and the expression of hepatic genes involved in one-carbon unit and formate metabolism.Results: Cobalamin-deficient rats produce formate at a rate 55% higher than that of replete rats. Formate production from serine was increased by 60% and from dimethylglycine and sarcosine by ∼200% in liver mitochondria isolated from cobalamin-deficient rats compared with cobalamin-replete rats. There was a 26% decrease in the 14CO2 produced by mitochondria from cobalamin-deficient rats. Gene expression analysis showed that 10-formyltetrahydrofolate dehydrogenase-cytosolic (Aldh1l1) and mitochondrial (Aldh1l2) expression were decreased by 40% and 60%, respectively, compared to control, while 10-formyltetrahydrofolate synthetase, mitochondrial, monofunctional (Mthfd1l) expression was unchanged.Conclusion: We propose that a bifurcation in mitochondrial one-carbon metabolism is a key control mechanism in determining the fate of one-carbon units, to formate or CO2. During cobalamin deficiency in rats the disposition of 10-formyl-tetrahydrofolate carbon is shifted in favor of formate production. This may represent a mechanism to generate more one-carbon units for the replenishment of the S-adenosylmethionine pool which is depleted in this condition. [ABSTRACT FROM AUTHOR]

We report synthesis of four novel heterometallic MOFs, [(NH 4 )(H 2 O)][Cr III M II (HCOO) 6 ] with M II = Zn (NH 4 CrZn), Co (NH 4 CrCo), Mn (NH 4 CrMn) and Ni (NH 4 CrNi). X-ray diffraction shows that NH 4 CrZn crystallizes in the trigonal structure (space group P 3 ¯ 1 c ) with ordered Cr 3+ and Zn 2+ centers while NH 4 CrCo, NH 4 CrMn and NH 4 CrNi crystallize in the hexagonal system with chiral space group of P 6 3 22 and statistical occupation of the same sites by Cr 3+ and M 2+ ions. Raman and IR data confirm presence of water molecules and different confinement of the ammonium cations in the cavities of chiral and niccolite type metal formate frameworks. Optical studies show that Cr 3+ ions in NH 4 CrZn and NH 4 CrMn are located at sites of strong crystal field with the Dq/B values of 2.54 and 2.47, respectively. Luminescence studies show that these compounds exhibit efficient Cr 3+ -based emission with the decay time of 8.1 μs (0.44 ms) at 295 K (10 K) for NH 4 CrMn and 8.3 μs (0.78 ms) for NH 4 CrZn. [ABSTRACT FROM AUTHOR]

A series of phosphinoyldithioformate compounds were synthesized from metathesis reactions of K[R 2 P(O)CS 2 ], and R' n PbCl 4-n and R’HgCl. The compounds isolated were characterized using infrared, UV and multinuclear NMR ( 1 H, 13 C, and 31 P) spectroscopy. Structural diversity of these compounds is revealed through analysis of the infrared and NMR spectroscopy, where variable temperature 31 P NMR spectroscopy data of 6 reveals non-rigid coordination behavior and an equilibrium of aniso bonded S,S 4-membered ring, and S,O bonded 5-membered ring bonding modes in [MeHg{S 2 CP(O)(Ph) 2 }], ( 6 – 6′ ). The crystal structure of 6′ shows the mercury atom in a T-shape geometry with S,O-bidentate coordinated ligand although room temperature NMR indicated the coordination to the mercury in 6 is non rigid in solution. Variable temperature 31 P NMR spectroscopy yielded an average value of ΔG # 6-6´ = 45.7 ± 1.7 kJ mol −1 for the temperature range of 190 K–283 K. The crystal structure of [Ph 2 Pb{S 2 CP(O)(Ph) 2 } 2 (H 2 O)], 1 , reveals the lead atom in an unusual seven coordinate geometry with two S,O-bidentate coordinated ligands and axial phenyl groups. The seventh ligand is a water molecule bonded to lead forming a pentagonal plane. [ABSTRACT FROM AUTHOR]

In this paper, composite silica gel and potassium formate as typical organic weak acid salts is proposed to use in desiccant coated heat exchanger (DCHE). An experimental study on dynamic adsorption performance of desiccant coated metal sheet samples is conducted to obtain results with different proportions of silica gel and potassium format. A DCHE testing platform is then used to compare thermodynamic performance between single silica gel coated heat exchanger (SCHE) and composite potassium formate and silica gel coated heat exchanger (PSCHE). It is found that impregnating potassium formate into porous silica gel is an effective method to improve adsorption capacity, and 75% saturated potassium formate solution is recommended to constitute composite desiccant under experimental conditions. Compared with SG coated sheet, on average the maximum adsorption mass of SG&0.75PF coated sheet increases 2–3 times. Besides, PSCHE can obtain about 20% higher moisture removal capacity compared with SCHE under experimental condition, meaning the utilization of composite silica gel and potassium formate desiccant can effectively improve dehumidification capacity. PSCHE also can obtain 50% higher total cooling capacity compared with SCHE. [ABSTRACT FROM AUTHOR]

ZrO 2 -supported Ni samples were prepared by an impregnation method and tested as catalysts for CO 2 methanation. Infrared spectra recorded during catalysis show that CO 2 was initially adsorbed in the form of carbonate and bicarbonate species bonded to sites of the support. The data indicate that bicarbonates were hydrogenated to give surface formate species, which reacted with H 2 at increasing temperature and led to the formation of methane, as evidenced by changes in the mass spectral signal of methane in the effluent gases from a flow reactor/DRIFT cell. No surface carbonyls were observed during the reaction. Separate experiments in which the catalysts were tested for the hydrogenation of methanol and formic acid also show their activity towards methane formation. In both cases, surface methoxy species bonded to Lewis acid sites of ZrO 2 were identified. Our results indicate a bifunctional character of the ZrO 2 -supported Ni catalysts for CO 2 methanation, with the CO 2 being activated on sites of the support and the role of Ni consisting on providing sites for hydrogen adsorption and dissociation. [ABSTRACT FROM AUTHOR]

Diastereomeric resolution of helically distorted polycondensed bisphenols (1,1′-bibenzo[ c ]phenanthrene-2,2′-diols: HEBPOLs) 2a – b was conducted utilizing (1 R )-(−)-menthyl chloroformate as a chiral resolving agent. Subsequent manipulation produced highly optically pure [>99% enantiomeric excess ( ee )] quinone derivatives ( P ) and ( M )- 1a – b in very good yields. The absolute configuration of each product was confirmed based on circular dichroism (CD) spectra and X-ray crystal structure analysis. [ABSTRACT FROM AUTHOR]

A modified method is reported for the conversion of unsaturated sulfonamides into their cyclic saturated counterparts. This method utilises a single palladium catalyst for an intramolecular Heck reaction and subsequent transfer hydrogenation, which is achieved in one-pot following the addition of ammonium formate. Accordingly, a range of fourteen structural variations are reported and under optimal conditions the adducts were generated in typically good to excellent yields. Notably, discrimination of differentially substituted dienes can be accomplished in the case of compounds 28 and 29 and the process was only observed to fail with the more sterically hindered precursor 32 . [ABSTRACT FROM AUTHOR]

The immobilization of NAD + -dependent dehydrogenases, in combination with a diaphorase, enables the facile development of multiparametric sensing devices. In this work, an amperometric biosensor array for simultaneous determination of ethanol, formate, d - and l -lactate is presented. Enzyme immobilization on platinum thin-film electrodes was realized by chemical cross-linking with glutaraldehyde. The optimization of the sensor performance was investigated with regard to enzyme loading, glutaraldehyde concentration, pH, cofactor concentration and temperature. Under optimal working conditions (potassium phosphate buffer with pH 7.5, 2.5 mmol L -1 NAD + , 2.0 mmol L -1 ferricyanide, 25 °C and 0.4% glutaraldehyde) the linear working range and sensitivity of the four sensor elements was improved. Simultaneous and cross-talk free measurements of four different metabolic parameters were performed successfully. The reliable analytical performance of the biosensor array was demonstrated by application in a clarified sample of inoculum sludge. Thereby, a promising approach for on-site monitoring of fermentation processes is provided. [ABSTRACT FROM AUTHOR]

A simple and straightforward semihydrogenation of alkyne to alkene with triethanolamine and formic acid in the presence of PdCl 2 has been described. Although hydrogenation using formic acid as a hydrogenation source has been used in combination with amines previously, few reports are available concerning the associated reactivity. We demonstrated that reactivity changes depending on the type of amine used in the hydrogenation. Further, this reaction requires no strict time control, making it a useful tool in organic synthesis. [ABSTRACT FROM AUTHOR]

Gas diffusion electrodes (GDEs), including GDE-In 0.90 Sn 0.10 , GDE-In 0.47 Sn 0.53 and GDE-In 0.22 Sn 0.78 , were prepared by electrodeposition of In–Sn alloys on carbon fiber paper, and then used to explore the electroreduction of CO 2 to formate in aqueous solution. Compared with commercial indium or Sn foil catalysts, the GDE-In 0.90 Sn 0.10 electrode in particular is shown to have excellent catalytic performance towards electroreduction of CO 2 to formate, with a high Faradaic efficiency (~ 92%). More importantly, the catalytic activity of GDE-In 0.90 Sn 0.10 remained reasonably stable over a 22-hour period of electrolysis, and a relatively high electrolytic current density (15 mA cm − 2 ) was obtained in an aqueous medium, demonstrating its potential for electrochemical reduction of CO 2 to formate. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO 2 has been considered as a promising method for the production of value-added chemicals. In this work, the electrochemical reduction of CO 2 to formate is carried out over novel carbon aerogel supported SnO 2 nanocrystals prepared by a facile hydrothermal method. The as prepared materials exhibit good catalytic activity and high formate selectivity. It is found that the content of SnO 2 plays an important role in the whole process, in which the formate is the exclusive product. At low SnO 2 content the catalyst shows poor activity due to the lack of active ingredients, while at high SnO 2 content it results in a dramatic decrease of the faradaic efficiency for the formate because of the blockage of part of active sites due to the agglomeration and poor conductivity of SnO 2 . It is also found that the optimized SnO 2 /CA-80 with 28.1 wt.% SnO 2 leads to the best performance, offering a relatively high faradaic efficiency of ∼76% for the formate formation in 1.0 mol/L KHCO 3 at −0.96 V ( vs . RHE). Moreover, the above catalyst exhibits excellent stability during the control potential electrolysis for 12 h. [ABSTRACT FROM AUTHOR]

In this work, we report heterogeneous catalysis of bicarbonate reduction to formate (FA) using silver nanoparticles (Ag NP) and silver nanoclusters (Ag NC) supported on multi-wall carbon nanotubes (MWCNT). FA detection was performed by substrate generation/tip collection (SG/TC) mode of scanning electrochemical microscopy (SECM) using Pt UME in 100 mM HCO 3 − at pH 8. The Ag NP and Ag NC showed high carbonate reduction current, and similar activity as massive gold electrode targets them as alternative catalysts for FA production. Prior to bicarbonate reduction, the electrochemical activity of Ag NP and Ag NC was evaluated using carbon fiber ultra microelectrodes (UME), these carbon UME were fabricated and characterized for use in SCEM mapping; carbon UME provided an excellent feedback response and are dispensable electrodes with renewable surfaces. Also, a carbon UME enables the fabrication of an enzymatic sensor which was designed for NAD + (Nicotine amide dinucleotide) dependent formate dehydrogenase immobilization. The enzymatic reaction coupled with the redox mediator 2,2V-Azino- bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) allowed a sensitive FA detection. The production of FA on silver particles and the FA detection methods presented in this work will be the target of further investigation for energy storage molecules. [ABSTRACT FROM AUTHOR]

Uniform NiS hierarchical hollow cubes were facilely fabricated by an anion exchange reaction of low-cost Ni formate framework precursor ([CH 3 NH 3 ][Ni(HCOO) 3 ]) with S 2− . The hierarchical hollow structure formed due to the Kirkendall effect and Ostwald ripening. When evaluated as electrode materials for supercapacitors, NiS hierarchical hollow cubes exhibited high specific capacitance (874.5 F g −1 at 1 A g −1 ) and good cycling stability (retention of 90.2% after 3000 cycles). Moreover, the as-fabricated asymmetric supercapacitor had an enhanced energy density of 34.9 Wh kg −1 at a power density of 387.5 W kg −1 . [ABSTRACT FROM AUTHOR]