Energy-saving H2 production from a hybrid acid/alkali electrolyzer assisted by anodic glycerol oxidation.

Water electrolysis is a promising technology for efficient hydrogen production, but it has been heavily hindered by the sluggish kinetics and high potential of the anodic oxygen evolution reaction (OER). Replacing the OER with the glycerol oxidation reaction (GOR) at the anode is recognized as a potential strategy to address this issue. In this work, the self-supported electrocatalytic electrode of Cu-Cu2O nanoclusters on carbon cloth (Cu-Cu2O/CC) is fabricated for the electrocatalysis of the GOR, which has high activity towards the GOR, reaching 10 mA cm-2 at an applied voltage of 1.21 V, and shows high selectivity for formate production with a faradaic efficiency (FE) of over 80% in a wide potential range. Moreover, a hybrid acid/alkali electrolyzer is assembled by coupling the Cu-Cu2O/CC anode for the GOR in an alkaline electrolyte with commercial Pt/C as the cathode for the hydrogen evolution reaction (HER) in an acid electrolyte. The dual-electrolyte electrolytic cell only requires an applied voltage of 0.59 V to reach 10 mA cm-2 with a FE of ∼100% for H2 and 97% for formate production. This work provides a facile strategy for the application of glycerol upgradation in energy-saving water electrolysis systems.

High Entropy Alloy Electrocatalytic Electrode toward Alkaline Glycerol Valorization Coupling with Acidic Hydrogen Production.

Electrochemical glycerol oxidation reaction (GOR) is an attractive alternative anodic reaction to oxygen evolution reaction for a variety of electrolytic synthesis, thanks to the possibility of mass production of glycerol from biomass and the relative low thermodynamic potential of GOR. The development of high-activity cheap electrocatalysts toward GOR yet faces a daunting challenge. Herein, we experimentally prepare a new range of high entropy alloy (HEA) self-supported electrodes with uniform HEA nanoparticles grown on carbon cloth. The systematic electrochemical studies verify that the HEA-CoNiCuMnMo electrode exhibits attractive performance for GOR electrocatalysis with low overpotential and high selectivity toward formate products. The surface atomic configurations of HEA-CoNiCuMnMo are studied by a self-developed machine learning-based Monte Carlo simulation, which points out the catalytic active center to be Mo sites coordinated by Mn, Mo, and Ni. We further develop a hybrid alkali/acid flow electrolytic cell by pairing alkaline GOR with acidic hydrogen evolution reaction using the HEA-CoNiCuMnMo and the commercial RhIr/Ti as the anode and the cathode, respectively, which only requires an applied voltage of 0.55 V to reach an electrolytic current density of 10 mA cm-2 and maintains long-term electrolysis stability over 12 days continuous running at 50 mA cm-2 with Faraday efficiencies of over 99% for H2 in the cathode and 92% for formate production in the anode.

Electrocatalysis for CO2 conversion: from fundamentals to value-added products.

The continuously increasing CO2 released from human activities poses a great threat to human survival by fluctuating global climate and disturbing carbon balance among the four reservoirs of the biosphere, earth, air, and water. Converting CO2 to value-added feedstocks via electrocatalysis of the CO2 reduction reaction (CO2RR) has been regarded as one of the most attractive routes to re-balance the carbon cycle, thanks to its multiple advantages of mild operating conditions, easy handling, tunable products and the potential of synergy with the rapidly increasing renewable energy (i.e., solar, wind). Instead of focusing on a special topic of electrocatalysts for the CO2RR that have been extensively reviewed elsewhere, we herein present a rather comprehensive review of the recent research progress, in the view of associated value-added products upon selective electrocatalytic CO2 conversion. We initially provide an overview of the history and the fundamental science regarding the electrocatalytic CO2RR, with a special introduction to the design, preparation, and performance evaluation of electrocatalysts, the factors influencing the CO2RR, and the associated theoretical calculations. Emphasis will then be given to the emerging trends of selective electrocatalytic conversion of CO2 into a variety of value-added products. The structure-performance relationship and mechanism will also be discussed and investigated. The outlooks for CO2 electrocatalysis, including the challenges and opportunities in the development of new electrocatalysts, electrolyzers, the recently rising operando fundamental studies, and the feasibility of industrial applications are finally summarized.

Molten-Salt-Assisted Synthesis of Bismuth Nanosheets for Long-term Continuous Electrocatalytic Conversion of CO2 to Formate.

Two-dimensional (2D) monometallic pnictogens (antimony or Sb, and bismuth or Bi) nanosheets demonstrate potential in a variety of fields, including quantum devices, catalysis, biomedicine and energy, because of their unique physical, chemical, electronic and optical properties. However, the development of general and high-efficiency preparative routes toward high-quality pnictogen nanosheets is challenging. A general method involving a molten-salt-assisted aluminothermic reduction process is reported for the synthesis of Sb and Bi nanosheets in high yields (>90 %). Electrocatalytic CO2 reduction was investigated on the Bi nanosheets, and high catalytic selectively to formate was demonstrated with a considerable current density at a low overpotential and an impressive stability. Bi nanosheets continuously convert CO2 into formate in a flow cell operating for one month, with a yield rate of 787.5 mmol cm-2 h-1 . Theoretical results suggest that the edge sites of Bi are far more active than the terrace sites.

N-Doped Carbon Nanofibers with Interweaved Nanochannels for High-Performance Sodium-Ion Storage.

Although graphite materials have been applied as commercial anodes in lithium-ion batteries (LIBs), there still remain abundant spaces in the development of carbon-based anode materials for sodium-ion batteries (SIBs). Herein, an electrospinning route is reported to fabricate nitrogen-doped carbon nanofibers with interweaved nanochannels (NCNFs-IWNC) that contain robust interconnected 1D porous channels, produced by removal of a Te nanowire template that is coelectrospun within carbon nanofibers during the electrospinning process. The NCNFs-IWNC features favorable properties, including a conductive 1D interconnected porous structure, a large specific surface area, expanded interlayer graphite-like spacing, enriched N-doped defects and active sites, toward rapid access and transport of electrolyte and electron/sodium ions. Systematic electrochemical studies indicate that the NCNFs-IWNC exhibits an impressively high rate capability, delivering a capacity of 148 mA h g-1 at current density of as high as 10 A g-1 , and has an attractively stable performance over 5000 cycles. The practical application of the as-designed NCNFs-IWNC for a full SIBs cell is further verified by coupling the NCNFs-IWNC anode with a FeFe(CN)6 cathode, which displays a desirable cycle performance, maintaining acapacity of 97 mA h g-1 over 100 cycles.

Hollow black TiAlOx nanocomposites for solar thermal desalination.

Although a solar-thermal conversion technique shows great potential for seawater desalination, there remains a grand challenge in exploring low-cost and high-efficiency photothermal materials. We report here a molten salt assisted galvanic replacement method for preparing a hollow black TiAlOx composite, which features a high solar absorptivity with up to 90.2% and has a high efficiency of 71.1% in a high salinity solution containing 15.3 wt% NaCl (∼5 times more concentrated than seawater). We exemplify the practical application of such hollow black TiAlOx composites as photothermal composites by setting up the automatic and manual tracking of solar desalination devices with a photic area of ∼1.0 m2, which can produce purified water with a rate of above 4.0 L m-2 day-1 in high-salinity water under natural light irradiation, and maintains good stability upon 5 days of continuous running. The advantages of the as-developed hollow black TiAlOx composites, including scalability, low cost, and high photothermal conversion efficiency, may open up a promising avenue practical application in seawater desalination.

Self-supported bimetallic Ni-Co compound electrodes for urea- and neutralization energy-assisted electrolytic hydrogen production.

Hydrogen represents one of the most promising renewable energy sources for next generation energy systems, however, its large scale production is high cost and high energy. A proof-of-concept alkaline-acid electrolyzer is reported here that can significantly reduce the amount of electrical energy consumed in electrolytic hydrogen production, implemented by the development of self-supported bimetallic Ni-Co compound electrodes used as the anode and cathode, respectively, where a urea oxidation reaction (UOR) occurs at the alkaline Ni0.67Co0.33(OH)2 nanosheet anode, coupled to the hydrogen evolution reaction (HER) at the acidic Ni0.67Co0.33S2 cathode. The asymmetric-electrolyte electrolyzer can efficiently harvest two kinds of energies, i.e. electrochemical neutralization energy (ENE) and electrochemical urea oxidation energy, to assist electrolytic hydrogen production using waste urea, acid, and base. The as-designed electrolyzer can deliver a current density of 10 mA cm-2 for electrolytic H2 generation with a rather low applied voltage of 0.54 V, with the potential to use up waste urea, acid and base.

Perfluorinated Covalent Triazine Framework Derived Hybrids for the Highly Selective Electroconversion of Carbon Dioxide into Methane.

Developing cost-effective electrocatalysts for high-selectivity CO2 electroreduction remains challenging. We herein report a perfluorinated covalent triazine framework (CTF) electrocatalyst that displays very high selectivity in the electroreduction of CO2 to CH4 with a faradaic efficiency of 99.3 % in aqueous electrolyte. Systematic characterization and electrochemical studies, in combination with density functional theory calculations, demonstrate that the presence of both nitrogen and fluorine in the CTF provides a unique pathway that is inaccessible with the individual components for CO2 electroreduction.

Alkaline-Acid Zn-H2 O Fuel Cell for the Simultaneous Generation of Hydrogen and Electricity.

An alkaline-acid Zn-H2 O fuel cell is proposed for the simultaneous generation of electricity with an open circuit voltage of about 1.25 V and production of H2 with almost 100 % Faradic efficiency. We demonstrate that, as a result of harvesting energy from both electrochemical neutralization and electrochemical Zn oxidation, the as-developed hybrid cell can deliver a power density of up to 80 mW cm-2 and an energy density of 934 Wh kg-1 and maintain long-term stability for H2 production with an output voltage of 1.16 V at a current density of 10 mA cm-2 .

Energy-efficient electrolytic hydrogen production assisted by coupling urea oxidation with a pH-gradient concentration cell.

An unprecedented asymmetric-electrolyte electrolyzer is proposed using an acidic cathode for the hydrogen evolution reaction (HER) and an alkaline anode for the urea oxidation reaction (UOR), which significantly decreases the electrical energy required for electrolytic hydrogen production.

Lanthanum lead oxide hydroxide nitrates with a nonlinear optical effect.

Two new lanthanum lead oxide hydroxide nitrates with acentric structure, [LaPb8O(OH)10(H2O)](NO3)7 (1) and [LaPb8O(OH)10(H2O)](NO3)7·2H2O (2), have been prepared under subcritical hydrothermal conditions and crystallize in the space groups of Cc and P2(1)2(1)2(1), respectively. The crystal structure of compound 1 consists of the novel [LaPb8O(OH)10(H2O)](7+) clusters regularly arranged along the ab plane with nitrate ions as the counterions around the clusters by Pb-O bonds, developing into a three-dimensional net framework, while the structure of compound 2 is composed of [LaPb8O(OH)10(H2O)](7+) clusters and [NO3](-) groups as the bridging groups, forming a three-dimensional net framework with crystallized water molecules filling in the gaps. The experiments confirmed that compound 1 is the residue of compound 2 after efflorenscence. Besides, the [LaPb8O(OH)10(H2O)](7+) clusters present mirror symmetry in structures of the two compounds. The second-harmonic-generation (SHG) measurements for the two nitrates indicate that the SHG responses for compounds 1 and 2 are 1.3 and 1.1 times that of KH2PO4, respectively. Theoretical calculations confirmed that the SHG efficiency of compounds 1 and 2 mainly arises from the NO3(-) groups in the structure.

Na4La2(CO3)5 and CsNa5Ca5(CO3)8: two new carbonates as UV nonlinear optical materials.

Two nonlinear optical crystal carbonates (Na4La2(CO3)5 and CsNa5Ca5(CO3)8 were successfully synthesized by hydrothermal method, and both of them crystallized in the same noncentrosymmetric hexagonal space group P63mc (No. 186). The structure of Na4La2(CO3)5 consists of a three-dimensional network made up of [CO3] triangles as well as irregular [Na(0.67)La(0.33)O10] and [NaO8] polyhedra. The structure of CsNa5Ca5(CO3)8 can be described as the standing-on-edge [CO3] groups connect the adjacent infinite [CaCO3]∞ layers in the ab plane to construct a framework with four types of channels running parallel to [010]. The Na, Cs, and [Na(0.67)Ca(0.33)] atoms reside in these channels. The measurement of second harmonic generation (SHG) by the method adapted from Kurtz and Perry indicated that Na4La2(CO3)5 and CsNa5Ca5(CO3)8 were phase-matchable in the visible region and exhibited SHG responses of approximately 3 and 1 × KH2PO4 (KDP). Meanwhile, they exhibited wide transparent region with short UV cutoff edge at about 235 and 210 nm, respectively, suggesting that these crystals as NLO materials may have potential applications in the UV region.

[Exploration and research of community management model for asthmatic children].

OBJECTIVE: To study the efficacy of community management model of bronchial asthma in children. METHOD: Through community outreach and clinic, 120 cases of children with asthma were enrolled from the 11 000 children aged 0 to 14 in Zhanlanlu area, and a community management model of asthma was established according to the Global Initiative for Asthma requirements combined with the actual situation of the community, both physicians and patients participated in case identification, file creation, and long-term standardized management. Through repeated medical education, the telephone hotline and interactive network of asthma among physicians, children and parents, a physician-patient relationship was established. The data of standardized medication, scheduled re-visit to the hospital, frequency of asthma attacks, antibiotic use, medical expenses, the loss of parents work hours etc. before and after the implementation of community management model were analyzed and compared. RESULT: After implementation of community management model, the use of systemic corticosteroids (19.4%), oral medication (31.6%) was significantly lower than those before implementation (68.3% and 90.0%) (χ(2) = 51.9, 41.1, P < 0.01), use of inhaled corticosteroids (76.5%) and oral leukotriene receptor antagonist (79.6%) was significantly higher compared with control and before management level (10.0%), χ(2) = 106.0, P < 0.01. The days of attacks of asthma (4.6 ± 2.3), the use of antibiotics (16.2 ± 6.1), (5.7 ± 2.9) and the cost of treatment significantly decreased. In 16 cases (13.3%) two-way referral was applied. In this study, the dropout rate was 18.3%, by telephone and network supervision of lost cases, re-education, made some children return to management, eventually the dropout rate was 9.2%. CONCLUSION: Enrollment of children with bronchial asthma into community management model made the children adhere to the management regularly and a standardized management was achieved.

Series of lead oxide hydroxide nitrates obtained by adjusting the pH values of the reaction systems.

A series of lead(II) nitrates have been synthesized by a hydrothermal method and adjusting the pH values of the reaction systems. Pb20O6(OH)16(NO3)12 and Pb2O(OH)NO3, crystallize in the centrosymmetric space group P1̅ and Pbca, respectively. The structure of Pb20O6(OH)16(NO3)12 features infinite cationic chains of [Pb20O6(OH)16]∞ running along c axis, and the nitrate groups as the counterions reside between adjacent chains, while the structure of Pb2O(OH)NO3 can be described as alternate stacking of cationic [Pb2O(OH)]∞ layers with anionic [NO3](-) layers along [001] direction by the weak Pb-O bonds, forming a 3D framework with 1D tunnels of 12-member rings (MRs). [Pb4(OH)4](NO3)4, crystallizing in the noncentrosymmetric space group Cc, has been studied as the nonlinear optical material for the first time. The second harmonic generation (SHG) measurement indicates that the SHG responses of [Pb4(OH)4](NO3)4 are 0.7 times that of KDP. Theoretical calculations confirmed the SHG efficiency of [Pb4(OH)4](NO3)4 originates from the cooperative effect of NO3(-) groups and lead oxygen polyhedras in the structure. Meanwhile, the relationship between pH value and ratio of Pb/OH(-) in the molecules presents a positive correlation, which results in the diversity of these structures under different pH value.