A Cu-Pd alloy catalyst with partial phase separation for the electrochemical CO_(2) reduction reaction

Cu catalysts can convert CO_(2) through an electrochemical reduction reaction into a variety of useful carbon-based products.However,this capability provides an obstacle to increasing the selectivity for a single product.Herein,we report a simple fabrication method for a Cu-Pd alloy catalyst for use in a membrane electrode assembly(MEA)-based CO_(2) electrolyzer for the electrochemical CO_(2) reduction reaction(ECRR)with high selectivity for CO production.When the composition of the Cu-Pd alloy catalyst was fabricated at 6:4,the selectivity for CO increased and the production of multi-carbon compounds and hydrogen is suppressed.Introducing a Cu-Pd alloy catalyst with 6:4 ratio as the cathode of the MEAbased CO_(2) electrolyzer showed a CO faradaic efficiency of 92.8%at 2.4 V_(cell).We assumed that these results contributed from the crystal planes on the surface of the Cu-Pd alloy.The phases of the Cu-Pd alloy catalyst were partially separated through annealing to fabricate a catalyst with high selectivity for CO at low voltage and C_(2)H_4 at high voltage.The results of CO-stripping testing confirmed that when Cu partially separates from the lattice of the Cu-Pd alloy,the desorption of~*CO is suppressed,suggesting that C-C coupling reaction is favored.

Preparation of nanoanatase and its in situ XRD study

Phase pure nanoanatase was prepared by sol-hydrolysis of TiCl4 in ammonium sulfate solution.In order to investigate the microstrain effect on nanoanatase transformation,the transformation process of the sample was investigated by in situ XRD.Based on the in situ XRD data,a variation of the diameter and its distribution,and the microstrain of nanotitania particles were estimated with Win XRD software.The results show that the transformation process of nanoanatase can be divided into four steps;a rate competition between the anatase growth and the transformation from anatase to rutile determines the diameter and its size distribution of anatase nanoparticles;and during the phase transformation,the microstrain determines the rates of anatase growth and its transformation.

Heterogeneous activation of persulfate by CuMgAl layered double oxide for catalytic degradation of sulfameter

In this study,a series of CuMgAl layered double oxides(CuMgAl-LDOs)were obtained via calcination of CuMgAl layered double hydroxides(CuMgAl-LDHs)synthesised via a co-precipitation method.The results show that CuMgAl-LDO can be prepared using an optimal Cu:Mg:Al molar ratio of 3:3:2,NaOH:Na_(2)CO_(3)molar ratio of 2:1,and calcination temperature of 600°C.CuMgAl-LDO is a characteristic of mesoporous material with a lamellar structure and large specific surface area.The removal efficiency of sulfameter(SMD)based on CuMgAl-LDO/persulfate(PS)can reach>98%over a wide range of initial SMD concentrations(5–20 mg L^(-1)).The best removal efficiency of99.49%was achieved within 120 min using 10 mg L^(-1)SMD,0.3 g L^(-1)CuMgAl-LDO,and 0.7 mmol L^(-1)PS.Kinetic analysis showed that the degradation of SMD was in accordance with a quasi-first-order kinetic model.The stability of the CuMgAl-LDO catalyst was verified by the high SMD removal efficiency(>97%within 120 min)observed after five recycling tests and low copper ion leaching concentration(0.89 mg L^(-1)),which is below drinking water quality standard of 1.3 mg L^(-1)permittable in the U.S.Radical scavenging experiments suggest that SO_(4)^(-)is the primary active species participating in the CuMgAl-LDO/PS system.Moreover,our mechanistic investigations based on the radical scavenging tests and X-ray photoelectron spectroscopy(XPS)results indicate that Cu^((II))-Cu^((III))-Cu^((II))circulation is responsible for activating PS in the degradation of SMD and the degradation pathway for SMD was deduced.Accordingly,the results presented in this work demonstrate that CuMgAl-LDO may be an efficient and stable catalyst for the activation of PS during the degradation of organic pollutants.

High-value Applications of Nanocellulose

Nanocelluloses, obtained from the biopolymer cellulose, are a class of renewable functional nanomaterials with excellent properties and a broad range of applications. This review mainly illustrates practical and advanced applications of nanocellulose-based materials in the following categories.(1) Fire-resistant materials: in the section on these types of materials, the fireprotection property of nanocellulose/clay hybrid composites(clay nanopaper) is illustrated; oriented montmorillonite(MTM) provides barrier properties and low thermal conductivity whereas cellulose nanofibers(CNFs) impart favorable charring.(2) Thermal insulation materials: the best way to obtain materials with good heat insulation performance is to decrease the thermal conductivity of such materials.(3) Template materials: nanocellulose can direct the deposition and patterning of materials to form nanoparticles, nanowires, or nanotubes with improved properties.

Simultaneous synthesis of heat-integrated water networks by a nonlinear program:Considering the wastewater regeneration reuse

Heat-integrated water network synthesis(HIWNS)has received considerable attention for the advantages of reducing water and energy consumptions.HIWNS is effective in water and energy sustainability.Mixed integer non-linear programming(MINLP)is usually applied in HIWNS.In this work,a novel nonlinear programming(NLP)was proposed for HIWNS by considering wastewater reuse and wastewater regeneration reuse.Integer variables are changed to non-linear equation by the methods for identifying stream roles and denoting the existence of process matches.The model is tested by examples with single and multiple regeneration unit problems.The testing results showed that the NLP is an alternative method for HIWNS with wastewater reuse and regeneration reuse.

在1-乙基咪唑三氟乙酸盐离子液体中合成的聚吡咯对草酸的电催化氧化(英文)

The electrochemical oxidation of oxalic acid is important in environmental engineering.In this paper,polypyrrole（PPy）was prepared galvanostatically in an ionic liquid 1-ethylimidazolium trifluoroacetate（HEImTfa）and its electro-catalysis function for the electrochemical oxidation of oxalic acid was investigated by using cyclic voltammetry.The results showed that the electro-catalytic activity of PPy prepared in HEImTfa（PPy-HEImTfa）was greatly improved as compared with that prepared in conventional H2SO4 aqueous solution.Therefore,the use of HEImTfa as growth electrolyte and solvent for electro-polymerization of pyrrole resulted in an electrochemically catalytic film of PPy for the electro-oxidation of oxalic acid.

Research progress of defect-engineered UiO-66(Zr)MOFs for photocatalytic hydrogen production

In recent years,defect-engineered Zr-based UiO-66 metal-organic frameworks(UiO-66(Zr)metalorganic frameworks(MOFs))have shown huge advantages in catalytic,functional materials,adsorption,and other fields due to their large surface areas,well-ordered porous structures,and flexible tailorability.It is extremely challenging to introduce defect sites in the synthesis of MOFs to regulate the physicochemical properties of materials such as(energy band structure,pore structure,etc.)to obtain an excellent performance.This paper reviews the recent research results of synthesis methods,characterization technologies,and application fields of defect-engineered UiO-66(Zr)MOFs materials in order to provide new insights to synthesize high-performance UiO-66(Zr)MOFs materials and promote the development of UiO-66(Zr)in various fields.