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Conversion of carbon dioxide (CO2) to valuable chemicals and feedstocks through electrochemical reduction holds promise for achieving carbon neutrality and mitigating global warming. C2+ products are of interest due to their higher economic value. Since the CO2 to C2+ conversion process involves multiple steps, tandem catalytic strategies are commonly employed in the design of electrochemical CO2 reduction reaction (CO2RR) catalysts and systems/reactors. Among the diverse catalysts that are capable of reducing CO2 to CO, Cu stands out for more efficiently further converting CO to C2+ products. In this review, the emerging Cu‐based tandem catalysts and their impact on CO2RR performance, focusing on three positional relationships are summarized. It delves into the integration of tandem catalytic strategies into membrane electrolyzers, utilizing catalyst‐coated substrate (CCS) and catalyst‐coated membrane (CCM) technologies. Several typical examples are presented to illustrate this integration. Finally, the challenges and prospects of applying tandem strategies in the development of CO2RR catalysts/systems, as well as their device‐level implementation are indicated. [ABSTRACT FROM AUTHOR]

A new study investigates the deposition of Y-123 films using spray pyrolysis on textured Ag ribbons at room temperature.

Due to the high growth rate and environmental‐friendly, fluorine‐free metal‐organic decomposition routes (FF‐MOD) have attracted more attention for growth of high‐quality YBa2Cu3O7‐δ (YBCO) films. Few works have been performed when using technical substrates. In this study, correlation among the sintering process, microstructure, and superconductivity of the YBCO was systematically established on the technical substrates capped with CeO2 layer. We found that the optimal process conditions are mainly related to the enhanced transient liquid phase and BaCeO3. Combined X‐ray diffraction and scanning electron microscopy analyses indicate that high‐quality growth of YBCO film is a trade‐off of two different competition phenomena during sintering: (a) the presence of enhanced transient liquid phase, (b) the formation of BaCeO3 at the interface. The former is beneficial to YBCO epitaxial growth/structure rearrangement, while the latter should be suppressed in view of minimizing YBCO partial decomposition triggered by the interfacial reaction. Moreover, we confirmed that both two aforementioned phenomena are somehow associated with the cross‐linkage between the sintering temperature and pO2 during the YBCO conversion. According to this systemic study, the key parameters are defined to avoid the BaCeO3 formation prior to the YBCO orientation nucleation. Structure and superconductivity of the YBCO film were also investigated. Remarkably, a high Jc value of 3.69 mA/cm2 (77 K, sf) was obtained in the YBCO film grown on the CeO2 technical substrate deposited under optimized deposition conditions, which is rather comparable with that on the LaAlO3 single crystal. TEM cross‐sectional observation reveals that the enhanced Jc (B) properties of the YBCO film are mainly contributed by high density of short stacking faults. This work demonstrates the feasibility of FF‐MOD to fabricate high‐performance YBCO films on the CeO2‐buffered technical substrate. [ABSTRACT FROM AUTHOR]

Abstract: This paper states the epitaxial growth of La2Zr2O7(LZO) buffer layers on the cube textured nickel alloy substrate, with the nitrate as the precursor. The solution stability and the heat treatment processing were discussed respectively. The solution of hydrated nitrates dissolved in ethanol being a sol at a higher temperature, the precursor was pre-dried and methanol was substituted with a higher dielectric constant. Because of the multi-step decomposition of the nitrates, a multi-step heat treatment route was followed, the complete decomposition of the intermediate phases being essential. The orientation analysis shows a cube textured film with the FWHM values of the (222) phi-scan and of the (400) ω-scan being 8.50° and 8.10° respectively. The SEM image shows a dense and homogeneous film without cracks and holes. The analysis above indicates that the present route is feasible for the preparation of LZO buffer layers [Copyright &y& Elsevier]

This paper focused on the modification properties of the La2Zr2O7 (LZO) seed layers for the epitaxial growth of thick LZO buffer films on cube-textured Ni5%W (Ni5W) substrate by the metal organic deposition (MOD) method. The surface morphologies of the LZO seed layers with different precursor concentrations were described by SEM. The grain orientation and the crystallographic growth model of the LZO seed layer were characterized by the electron backscatter diffraction (EBSD). The XRD analyses reveal that the LZO buffer layers on the Ni5W substrates with and without seed layers were grown epitaxially. However, the uniformly distributed islanded LZO seed layers with highly (001)[110] rotated cube texture not only can improve the crystallinity of the subsequent LZO buffer films, but also can optimize the in-plan and out-plan orientations of the thick LZO buffer layers. [ABSTRACT FROM AUTHOR]

CeO2 caped La2Zr2O7(LZO) buffer layers on cube-textured Ni5W substrates were fabricated by the method of chemical solution deposition(CSD). The orientation of both LZO film and CeO2 /LZO buffer layer was investigated using conventional XRD and X-ray four circle diffractometers, respectively. The results reveal that both the LZO film on Ni5W substrates and CeO2 film on LZO buffer layer are grown epitaxially. The value of Full Width at Half Maximum (FWHM) of (111) Phi scan of CeO2/LZO buffer layer is around 8°, and the FWHM of (200) w-scan of CeO2/La2Zr2O7 buffer layer is 6.5°, indicating a good in-plan orientation of the as obtained buffer layers. It was observed by the high resolution SEM that the surface of LZO buffer layer is crack-free and very dense. The surface result observed by AFM indicates a very smooth CeO2 surface with 5.9 nm of the root mean square roughness measured in an areas of 30 x 30 μm2. AES depth profile results of CeO2/LZO buffer layers shows that the deposited LZO film could effectively prevent the diffusion of Ni into the buffer layer. [ABSTRACT FROM AUTHOR]

YBa2Cu3O7-δ (YBCO) films with Zr doping have been prepared successfully by the trifluoroacetate metal-organic deposition (TEA-MOD) method through dissolving Zr acetylacetonate into the precursor solution. Yttria-stabilized zirconia(YSZ)nanoparticles were detected in the doped YBCO films by XRD. From the analysis of XRD ω and φ scans, the doped films have better out-of-plane and in-plane textures than those of the un-doped YBCO film. Although the doped YBCO films have lower Tc than that of the un-doped YECO film, a very significant enhancement of normalized Jc is displayed as compared to the undoped film at applied fields, indicating that an effective pinning force was created by Zr doping. [ABSTRACT FROM AUTHOR]

A sharp cube textured alloy substrates with high strength and low magnetism are required in coated conductors' applications. In this work, the cube textured Ni-7at.%W substrates, starting from advanced powder metallurgy ingots followed by Rolling Assisted Biaxially Textured Substrate (RABiTS) method, have been prepared. The fabrication processes of Ni-7at.%W tapes with sharp cube texture by spark plasma sintering(SPS) routes were described. By Electron Back Scattering Diffraction (EBSD) analysis, the percentage of the cube texture component in Ni-7at. %W tape surface is found to reach 99.4% within a misorientation angle smaller than 10°. Moreover, the formation mechanism of the cube texture in the Ni-7at. %W tape was also investigated by EBSD. Particular attention was focused on the difference of the texture components along the thickness of the partially recrystallized samples. [ABSTRACT FROM AUTHOR]

The anisotropy of the critical current density of Fe-sheathed ex situ MgB2 monofilamentary tapes has been measured at various magnetic fields and temperatures and has been found to be influenced by the particle size of the starting material. Already reacted powders were milled in order to obtain different starting particle sizes. In order to understand the origin of the anisotropy, we have undertaken an X-ray study on the degree of texturing in the filaments after mechanical removal of the Fe sheath. The degree of texturing of the filaments at the interface Fe/MgB2 and at the center of the filaments has been determined. A moderate texture has been found, being slightly higher at the interface. [ABSTRACT FROM AUTHOR]

In this study, boron powder with different particle sizes was purified by both chemical and heat treatment methods. The reduction in the particle size can improve the chemical purification with no effort on the heat treatment. The superconducting properties of the powder drastically changed even with only a partial elimination of oxygen. On the one hand, less oxygen content resulted in high Tc and Jc values under the low magnetic field, and most importantly, a significant improvement in the superconducting connectivity (Af value). On the other hand, the degradation of Jc under a high field and a change in the pinning mechanism were also found, along with decreasing oxygen. This result indicated that oxygen, probably MgO, might act as the pinning center and as an obstacle for the supercurrent in MgB2 at the same time. This work paves the way for obtaining pure oxygen-free MgB2 and understanding the real effect of oxygen in MgB2. [ABSTRACT FROM AUTHOR]

Mixed metal oxide nanocomposites (NCs) comprising Cu-Sr (CS), Sr-Cd (SC), and Cd-Cu (CC) were fabricated via a sol-gel method. Structural investigations of fabricated samples were carried out via X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The Maxwell-Wagner model, attributing to poor conducting layers around the conducting grains, was indicated to be followed by all of the NCs while investigating the dielectric properties. The Space-charge polarization and hoping mechanism contributed to low AC conductivity at lower frequencies and high AC conductivity at higher frequencies. The as-synthesized NCs effectively degraded two toxic water contaminants, such as crystal violet (CV) and Congo red (CR). Furthermore, the NCs were also evaluated for humidity sensing measurements. All of the NCs indicated efficient response/recovery time with better stability. The extensive investigation suggested the synthesized NCs, well suited for various optical and microelectronic applications., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)