High yield electrosynthesis of oxygenates from CO using a relay Cu-Ag co-catalyst system.

As a sustainable alternative to fossil fuel-based manufacture of bulk oxygenates, electrochemical synthesis using CO and H2O as raw materials at ambient conditions offers immense appeal. However, the upscaling of the electrosynthesis of oxygenates encounters kinetic bottlenecks arising from the competing hydrogen evolution reaction with the selective production of ethylene. Herein, a catalytic relay system that can perform in tandem CO capture, activation, intermediate transfer and enrichment on a Cu-Ag composite catalyst is used for attaining high yield CO-to-oxygenates electrosynthesis at high current densities. The composite catalyst Cu/30Ag (molar ratio of Cu to Ag is 7:3) enables high efficiency CO-to-oxygenates conversion, attaining a maximum partial current density for oxygenates of 800 mA cm-2 at an applied current density of 1200 mA cm-2, and with 67 % selectivity. The ability to finely control the production of ethylene and oxygenates highlights the principle of efficient catalyst design based on the relay mechanism.

Pulsed electroreduction of low-concentration nitrate to ammonia.

Electrocatalytic nitrate (NO3-) reduction to ammonia (NRA) has emerged as an alternative strategy for effluent treatment and ammonia production. Despite significant advancements that have been achieved in this field, the efficient conversion of low-concentration nitrate to ammonia at low overpotential remains a formidable challenge. This challenge stems from the sluggish reaction kinetics caused by the limited distribution of negatively charged NO3- in the vicinity of the working electrode and the competing side reactions. Here, a pulsed potential approach is introduced to overcome these issues. A good NRA performance (Faradaic efficiency: 97.6%, yield rate: 2.7 mmol-1 h-1 mgRu-1, conversion rate: 96.4%) is achieved for low-concentration (≤10 mM) nitrate reduction, obviously exceeding the potentiostatic test (Faradaic efficiency: 65.8%, yield rate: 1.1 mmol-1 h-1 mgRu-1, conversion rate: 54.1%). The combined results of in situ characterizations and finite element analysis unveil the performance enhancement mechanism that the periodic appearance of anodic potential can significantly optimize the adsorption configuration of the key *NO intermediate and increase the local NO3- concentration. Furthermore, our research implies an effective approach for the rational design and precise manipulation of reaction processes, potentially extending its applicability to a broader range of catalytic applications.

Scalable Electrosynthesis of Formamide through C-N Coupling at the Industrially Relevant Current Density of 120†mA cm-2.

The scalable and durable electrosynthesis of high-valued organonitrogen compounds from carbon- and nitrogen-containing small molecules, especially operating at a high current density, is highly desirable. Here, a one-pot electrooxidation method to synthesize formamide (HCONH2 ) from methanol and ammonia over a commercial boron-doped diamond (BDD) catalyst is reported. The formamide selectivity from methanol and formamide Faradaic efficiency (FE HCONH 2 ${{_{{\rm HCONH}{_{2}}}}}$ ) achieve 73.2 % and 41.2 % at the current density of 120 mA cm-2 with high durability. The C-N bond originates from the nucleophilic attack of ammonia on an aldehyde-like intermediate. Impressively, an 8 L electrolyzer is employed for the pilot plant test over a 2200 cm2 BDD electrode, which exhibits 33.5 % FE HCONH 2 ${{_{{\rm HCONH}{_{2}}}}}$ at 120 mA cm-2 (current: 264 A) with a yield rate of 36.9 g h-1 , demonstrating the potential of this technique for large-scale electrosynthesis of formamide.

Electrosynthesis of formamide from methanol and ammonia under ambient conditions.

Electrochemical conversion of abundant carbon- and nitrogen-containing small molecules into high-valued organonitrogen compounds is alluring to reducing current dependence on fossil energy. Here we report a single-cell electrochemical oxidation approach to transform methanol and ammonia into formamide under ambient conditions over Pt electrocatalyst that provides 74.26% selectivity from methanol to formamide and a Faradaic efficiency of 40.39% at 100 mA cm-2 current density, gaining an economic advantage over conventional manufacturing based on techno-economic analysis. A 46-h continuous test performed in the flow cell shows no performance decay. The combined results of in situ experiments and theoretical simulations unveil the C-N bond formation mechanism via nucleophilic attack of NH3 on an aldehyde-like intermediate derived from methanol electrooxidation. This work offers a way to synthesize formamide via C-N coupling and can be extended to substantially synthesize other value-added organonitrogen chemicals (e.g., acetamide, propenamide, formyl methylamine).

Oxide-Derived Core-Shell Cu@Zn Nanowires for Urea Electrosynthesis from Carbon Dioxide and Nitrate in Water.

Urea electrosynthesis provides an intriguing strategy to improve upon the conventional urea manufacturing technique, which is associated with high energy requirements and environmental pollution. However, the electrochemical coupling of NO3- and CO2 in H2O to prepare urea under ambient conditions is still a major challenge. Herein, self-supported core-shell Cu@Zn nanowires are constructed through an electroreduction method and exhibit superior performance toward urea electrosynthesis via CO2 and NO3- contaminants as feedstocks. Both 1H NMR spectra and liquid chromatography identify urea production. The optimized urea yield rate and Faradaic efficiency over Cu@Zn can reach 7.29 µmol cm-2 h-1 and 9.28% at -1.02 V vs RHE, respectively. The reaction pathway is revealed based on the intermediates detected through in situ attenuated total reflection Fourier transform infrared spectroscopy and online differential electrochemical mass spectrometry. The combined results of theoretical calculations and experiments prove that the electron transfer from the Zn shell to the Cu core can not only facilitate the formation of *CO and *NH2 intermediates but also promote the coupling of these intermediates to form C-N bonds, leading to a high faradaic efficiency and yield of the urea product.

Engineering Nitrogen Vacancy in Polymeric Carbon Nitride for Nitrate Electroreduction to Ammonia.

Electrocatalytic nitrate reduction to ammonia is of great interest in terms of energy conservation and environmental protection. However, the development of abundant metal-free electrocatalysts with high activity, selectivity, and stability is still a big challenge. Herein, polymeric graphitic carbon nitride (g-C3N4) with controllable numbers of nitrogen vacancies is reported to exhibit high Faradaic efficiency (89.96%), selectivity (69.78%), and stability toward nitrate-to-ammonia conversion. 15N isotope labeling experiments prove the produced ammonia originating from nitrate reduction. The combined results of ex situ and in situ characterizations unveil the reaction pathway based on the captured critical intermediates. Density functional theory calculations reveal that nitrogen vacancies could introduce a new electron state at the Fermi level and promote the adsorption, activation, and dissociation of nitrate. An appropriate content of nitrogen vacancies is beneficial for modulating the adsorption energies of reaction intermediates (*NO, *NOH, *NH2, etc.), facilitating the enhancement in ammonia selectivity and Faradaic efficiency.

Efficient Electrosynthesis of Syngas with Tunable CO/H2 Ratios over Znx Cd1-x S-Amine Inorganic-Organic Hybrids.

Efficient electrochemical reduction of CO2 and H2 O into industrial syngas with tunable CO/H2 ratios, especially integrated with anodic organic synthesis to replace the low-value oxygen evolution reaction (OER), is highly desirable. Here, integration of controllable partial substitution of zinc (Zn) with amine incorporation into CdS-amine inorganic-organic hybrids is used to generate highly efficient electrocatalysts for synthesizing syngas with tunable CO/H2 ratios (0-19.7), which are important feedstocks for the Fischer-Tropsch process. Diethylenetriamine could enhance the adsorption and accelerate the activation of CO2 to form the key intermediate COOH* for CO formation. Zn substitution promoted the hydrogen evolution reaction (HER), leading to tunable CO/H2 ratios. Importantly, syngas and dihydroisoquinoline can be simultaneously synthesized by pairing with anodic semi-oxidation of tetrahydroisoquinoline in a Znx Cd1-x S-Amine ∥ Ni2 P two-electrode electrolyzer.

[Effect of methyleugenol on expression of MUC5AC in nasal mucosa of rats with allergic rhinitis].

Objective: To investigate the effect of methyleugenol on expression of MUC5AC in nasal mucosa of rats with allergic rhinitis (AR). Methods: Seventy-two Wistar rats were randomly divided into 6 groups:normal control group, AR group, loratadine group, low-dose methyleugenol group, middle-dose methyleugenol group and high-dose methyleugenol group with 12 rats in each group. AR was induced by intraperitoneal injection of ovalbumin in latter 5 groups. 10 mg loratadine q.d was given to rats in loratadine group by gavage; and 10 mg/kg, 20 mg/kg and 40 mg/kg methyleugenol were given by gavege q.d to rats in low-, middle-and high-dose methyleugenol groups, respectively. Nasal mucosa samples were obtained from rats at 1, 2, 4 and 6 weeks after drug intervention. The expression of MUC5AC protein and mRNA in nasal mucosa was detected by immunohistochemistry and real-time fluorescence quota PCR (RT-PCR), respectively. Results: Compared with AR, the percentage of cells staining positively for MUC5AC protein and the relative quantity of MUC5AC mRNA in middle-and high-dose methyleugenol groups were significantly decreased after 2 and 4 weeks of drug intervention (P<0.05), but no such decrease was observed in low-dose methyleugenol group at all time points (P>0.05). The percentage of cells with positive expression of MUC5AC protein and mRNA in loratadine group were significantly decreased after 1 week of administration (P<0.05). The percentage of cells with positive MUC5AC protein in middle-dose methyleugenol group was higher than that in loratadine group (P<0.05) after 6 week of drug intervention, but the difference was not seen in high-dose group (P>0.05). There was no significant difference in relative quantities of MUC5AC mRNA after 4 weeks of administration between high-and middle-dose methyeugenol groups and loratadine group (P>0.05). Conclusion: Methyleugenol can attenuate AR through inhibiting the expression of MUC5AC mRNA and protein in nasal mucosa of AR rats.

[The effect of 18ß-sodium glycyrrhetinic acid on the nasal mucosa epithelial cilia in rat models of allergic rhinitis].

OBJECTIVE: To investigate 18ß-sodium glycyrrhetinic acid impact on nasal mucosa epithelial cilia in rat models of allergic rhinitis (AR). METHOD: AR models were established by ovalbumin-induction. Wister rats were randomly divided into groups as normal group, model group, budesonide (0.2 mg/kg) group and sodium glycyrrhetinic acid (20 mg/kg and 40 mg/kg) group after the success of AR models. At 2 weeks and 4 weeks after treatment, the behavioral changes of rats were observed and recorded, and nasal septum mucosae were collected after 2 week and 4 week intervention, and the morphological changes of nasal mucosae were observed by electron microscope. RESULT: Model group developed typical AR symptoms, the total score in all animals was > 5. With budesonide and sodium glycyrrhetinic acid treatment, the AR symptoms were relieved, and the total scores were reduced significantly (P < 0.01). Compared with the model group: after 2 weeks' intervention, thick mucous secretions on the top of columnar epithelium cilia in rat nasal mucosa was significantly reduced, and cilia adhesion, lodging, shedding were relieved in budesonide group and sodium glycyrrhetinic acid group, the relieve in budesonide group was slightly better than that in sodium glycyrrhetinic acid group; after 4 week intervention, Cilia adhesion, lodging, shedding were completely vanished, and the cilia were ranged in regular direction in budesonide group and sodium glycyrrhetinic acid group. Cilia in sodium glycyrrhetinic acid (20 mg/kg) group was more orderly, smooth than that in budesonide group and sodium glycyrrhetinic acid group (40 mg/kg), and the condition of cilia in sodium glycyrrhetinic acid group (20 mg/kg) was similar to the normal group. CONCLUSION: 18ß-sodium glycyrrhetinic acid is effective to restrain the pathological changes of nasal mucosa cilia in rat models of AR.