F:Flammable;
7664-41-7Relevant articles and documents
Modulating Single-Atom Palladium Sites with Copper for Enhanced Ambient Ammonia Electrosynthesis
Cheng, Hao,Han, Lili,Lin, Lili,Liu, Xijun,Luo, Jun,Ou, Pengfei,Ren, Zhouhong,Rui, Ning,Song, Jun,Sun, Jiaqiang,Xin, Huolin L.,Zhuo, Longchao
, p. 345 - 350 (2021)
The electrochemical reduction of N2 to NH3 is emerging as a promising alternative for sustainable and distributed production of NH3. However, the development has been impeded by difficulties in N2 adsorption, protonation of *NN, and inhibition of competing hydrogen evolution. To address the issues, we design a catalyst with diatomic Pd-Cu sites on N-doped carbon by modulation of single-atom Pd sites with Cu. The introduction of Cu not only shifts the partial density of states of Pd toward the Fermi level but also promotes the d-2π* coupling between Pd and adsorbed N2, leading to enhanced chemisorption and activated protonation of N2, and suppressed hydrogen evolution. As a result, the catalyst achieves a high Faradaic efficiency of 24.8±0.8 % and a desirable NH3 yield rate of 69.2±2.5 μg h?1 mgcat.?1, far outperforming the individual single-atom Pd catalyst. This work paves a pathway of engineering single-atom-based electrocatalysts for enhanced ammonia electrosynthesis.
Efficient electrochemical reduction of nitrate to nitrogen on tin cathode at very high cathodic potentials
Katsounaros,Ipsakis,Polatides,Kyriacou
, p. 1329 - 1338 (2006)
The electrochemical reduction of nitrate on tin cathode at very high cathodic potentials was studied in 0.1 M K2SO4, 0.05 M KNO3 electrolyte. A high rate of nitrate reduction (0.206 mmol min-1 cm-2) and a high selectivity (%S) of nitrogen (92%) was obtained at -2.9 V versus Ag/AgCl. The main by-products were ammonia (8%) and nitrite (2O and traces of NO were also detected. As the cathodic potential increases, the %S of nitrogen increases, while that of ammonia displays a maximum at -2.2 V. The %S of nitrite decreases from 65% at -1.8 V to A cathodic corrosion of tin was observed, which was more intensive in the absence of nitrate. At potentials more negative than -2.4 V, small amounts of tin hydride were detected.
Synthesis, Pharmacological, and Biological Evaluation of 2-Furoyl-Based MIF-1 Peptidomimetics and the Development of a General-Purpose Model for Allosteric Modulators (ALLOPTML)
Sampaio-Dias, Ivo E.,Rodríguez-Borges, José E.,Yá?ez-Pérez, Víctor,Arrasate, Sonia,Llorente, Javier,Brea, José M.,Bediaga, Harbil,Vin?, Dolores,Loza, Mariá Isabel,Caaman?, Olga,Garciá-Mera, Xerardo,González-Diáz, Humberto
, p. 203 - 215 (2021)
This work describes the synthesis and pharmacological evaluation of 2-furoyl-based Melanostatin (MIF-1) peptidomimetics as dopamine D2 modulating agents. Eight novel peptidomimetics were tested for their ability to enhance the maximal effect of tritiated N-propylapomorphine ([3H]-NPA) at D2 receptors (D2R). In this series, 2-furoyl-l-leucylglycinamide (6a) produced a statistically significant increase in the maximal [3H]-NPA response at 10 pM (11 ± 1%), comparable to the effect of MIF-1 (18 ± 9%) at the same concentration. This result supports previous evidence that the replacement of proline residue by heteroaromatic scaffolds are tolerated at the allosteric binding site of MIF-1. Biological assays performed for peptidomimetic 6a using cortex neurons from 19-day-old Wistar-Kyoto rat embryos suggest that 6a displays no neurotoxicity up to 100 μM. Overall, the pharmacological and toxicological profile and the structural simplicity of 6a makes this peptidomimetic a potential lead compound for further development and optimization, paving the way for the development of novel modulating agents of D2R suitable for the treatment of CNS-related diseases. Additionally, the pharmacological and biological data herein reported, along with >20a000 outcomes of preclinical assays, was used to seek a general model to predict the allosteric modulatory potential of molecular candidates for a myriad of target receptors, organisms, cell lines, and biological activity parameters based on perturbation theory (PT) ideas and machine learning (ML) techniques, abbreviated as ALLOPTML. By doing so, ALLOPTML shows high specificity Sp = 89.2/89.4%, sensitivity Sn = 71.3/72.2%, and accuracy Ac = 86.1%/86.4% in training/validation series, respectively. To the best of our knowledge, ALLOPTML is the first general-purpose chemoinformatic tool using a PTML-based model for the multioutput and multicondition prediction of allosteric compounds, which is expected to save both time and resources during the early drug discovery of allosteric modulators.
New insight into hydroxyl-mediated NH3 formation on the Rh-CeO2 catalyst surface during catalytic reduction of NO by CO
Wang, Chengxiong,Xia, Wenzheng,Zhao, Yunkun
, p. 1399 - 1405 (2017)
Vibrational IR spectra and light-off investigations show that NH3 forms via the “hydrogen down” reaction of adsorbed CO and NO with hydroxyl groups on a CeO2 support during the catalytic reduction of NO by CO. The presence of water in the reaction stream results in a significant increase in NH3 selectivity. This result is due to water-induced hydroxylation promoting NH3 formation and the competitive adsorption of H2O and NO at the same sites, which inhibits the reactivity of NO reduction by NH3.
Cerium and tin oxides anchored onto reduced graphene oxide for selective catalytic reduction of NO with NH3 at low temperatures
Wang, Yanli,Kang, Ying,Ge, Meng,Zhang, Xiu,Zhan, Liang
, p. 36383 - 36391 (2018)
A series of cerium and tin oxides anchored on reduced graphene oxide (CeO2-SnOx/rGO) catalysts are synthesized using a hydrothermal method and their catalytic activities are investigated by selective catalytic reduction (SCR) of NO with NH3 in the temperature range of 120-280 °C. The results indicate that the CeO2-SnOx/rGO catalyst shows high SCR activity and high selectivity to N2 in the temperature range of 120-280 °C. The catalyst with a mass ratio of (Ce + Sn)/GO = 3.9 exhibits NO conversion of about 86% at 160 °C, above 97% NO conversion at temperatures of 200-280 °C and higher than 95% N2 selectivity at 120-280 °C. In addition, the catalyst presents a certain SO2 resistance. It is found that the highly dispersed CeO2 nanoparticles are deposited on the surface of rGO nanosheets, because of the incorporation of Sn4+ into the lattice of CeO2. The mesoporous structures of the CeO2-SnOx/rGO catalyst provides a large specific surface area and more active sites for facilitating the adsorption of reactant species, leading to high SCR activity. More importantly, the synergistic interaction between cerium and tin oxides is responsible for the excellent SCR activity, which results in a higher ratio of Ce3+/(Ce3+ + Ce4+), higher concentrations of surface chemisorbed oxygen and oxygen vacancies, more strong acid sites and stronger acid strength on the surface of the CeSn(3.9)/rGO catalyst.
Reduction of nitrate and nitrite ions over Ni-ZnS photocatalyst under visible light irradiation in the presence of a sacrificial reagent
Hamanoi, Osamu,Kudo, Akihiko
, p. 838 - 839 (2002)
Ni-doped ZnS photocatalysts (Zn0.999Ni0.001S) with a 2.4 eV energy gap showed activities for the reduction of nitrate and nitrite ions to nitrite, ammonia, and dinitrogen under visible light irradiation (λ > 420 nm) in the presence of methanol as a reducing reagent. The reduction of nitrate ions competed with that of water to form dihydrogen. The concentration of nitrate ions and loading a platinum cocatalyst affected the selectivity for the reduction products of nitrate ions.
Boosted electrocatalytic N2 reduction on fluorine-doped SnO2 mesoporous nanosheets
Liu, Ya-Ping,Li, Yu-Biao,Zhang, Hu,Chu, Ke
, p. 10424 - 10431 (2019)
The development of highly active and durable electrocatalysts toward the N2 reduction reaction (NRR) holds a key to ambient electrocatalytic NH3 synthesis. Herein, fluorine (F)-doped SnO2 mesoporous nanosheets on carbon cloth (F-SnO2/CC) were developed as an efficient NRR electrocatalyst. Benefiting from the combined structural advantages of mesoporous nanosheet structure and F-doping, the F-SnO2/CC exhibited high NRR activity with an NH3 yield of 19.3 μg h-1 mg-1 and a Faradaic efficiency of 8.6% at-0.45 V (vs RHE) in 0.1 M Na2SO4, comparable or even superior to those of most reported NRR electrocatalysts. Density functional theory calculations revealed that the F-doping could readily tailor the electronic structure of SnO2 to render it with improved conductivity and increased positive charge on active Sn sites, leading to the lowered reaction energy barriers and boosted NRR activity.
Built-in Electric Field Triggered Interfacial Accumulation Effect for Efficient Nitrate Removal at Ultra-Low Concentration and Electroreduction to Ammonia
Sun, Wu-Ji,Ji, Hao-Qing,Li, Lan-Xin,Zhang, Hao-Yu,Wang, Zhen-Kang,He, Jing-Hui,Lu, Jian-Mei
, p. 22933 - 22939 (2021)
A built-in electric field in electrocatalyst can significantly accumulate higher concentration of NO3? ions near electrocatalyst surface region, thus facilitating mass transfer for efficient nitrate removal at ultra-low concentration and electroreduction reaction (NO3RR). A model electrocatalyst is created by stacking CuCl (111) and rutile TiO2 (110) layers together, in which a built-in electric field induced from the electron transfer from TiO2 to CuCl (CuCl_BEF) is successfully formed. This built-in electric field effectively triggers interfacial accumulation of NO3? ions around the electrocatalyst. The electric field also raises the energy of key reaction intermediate *NO to lower the energy barrier of the rate determining step. A NH3 product selectivity of 98.6 %, a low NO2? production of ?1 is achieved, which are all the best among studies reported at 100 mg L?1 of nitrate concentration to date.
NO + H2 reaction on Pt(100). Steady state and oscillatory kinetics
Slinko, M.,Fink, T.,Loeher, T.,Madden, H. H.,Lombardo, S. J.,et al.
, p. 157 - 170 (1992)
The reaction of NO + H2 on Pt(100) was studied in the 10-6 mbar range between 300 and 800 K with mass spectrometry, work-function measurements, and video LEED. Both multiple steady states and kinetic oscillations were found. The principal reaction products were N2, H2O and NH3, and the activity and selectivity of the reaction were seen to depend on the partial pressure ratio pH(2)/pNO, on the surface temperature, and on the degree of surface reconstruction. Whereas the 1 × 1 surface of Pt was active for both N2 and NH3 formation, a well-annealed hex phase exhibited a low catalytic activity. The occurrence of defects during the 1 × 1 hex transition was shown to lead to enhanced N2 formation. At low pH(2)/pNO ratios, N2 formation was favored, while for large pH(2)/pNO ratios NH3 production was enhanced. Kinetic oscillations, as determined from variations in the N2, H2O and work-function signals, were found between 430 and 445 K.
Putting ammonia into a chemically opened fullerene
Whitener Jr., Keith E.,Frunze, Michael,Iwamatsu, Sho-Ichi,Murata, Shizuaki,Cross, R. James,Saunders, Martin
, p. 13996 - 13999 (2008)
We put ammonia into an open-cage fullerene with a 20-membered ring (1) as the orifice and examined the properties of the complex using NMR and MALDI-TOF mass spectroscopy. The proton NMR shows a broad resonance corresponding to endohedral NH3 at δH = -12.3 ppm relative to TMS. This resonance was seen to narrow when a 14N decoupling frequency was applied. MALDI spectroscopy confirmed the presence of both 1 (m/z = 1172) and 1 + NH3 (m/z = 1189), and integrated intensities of MALDI peak trains and NMR resonances indicate an incorporation fraction of 35-50% under our experimental conditions. NMR observations showed a diminished incorporation fraction after 6 months of storage at -10°C, which indicates that ammonia slowly escapes from the open-cage fullerene.
