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Dendritic growth is a common behavior during the electrodeposition of zinc, which degrades the compactness and thickness uniformity of the zinc film. In this work, a series of quaternary ammonium compounds (QAC) with different non-polar groups (based on the number of carbon atoms in non-polar groups represented as C1, C4, C8, C12 and C16, respectively) were introduced into the basic electrolyte to inhibit the zinc dendritic growth. The results showed that the deposition of zinc became smoother with the increase of non-polar group length, which was attributed to the fact that the non-polar groups of the additive limit the random diffusion of Zn2+ and changed the adsorption state of the surface, so that a uniform zinc film was obtained. Meanwhile, the Zn-Zn symmetric cells with the addition of C8 achieved a stable cycle time of over 600 h. But with the further increase of length (C12 and C16), the migration of Zn2+ to the electrode surface became extremely difficult for strong steric hindrance, resulting in a rough deposition morphology. • The non-polar groups of the selected additives have a hindering effect on zinc ions. • Regulating the hydrocarbon chain length of the nonpolar group of the additive change the zinc film morphology. • The additive with appropriate hydrocarbon chain length obtain uniform zinc deposition. [ABSTRACT FROM AUTHOR]

Modulating the morphology of metal-organic frameworks (MOFs) has been identified as an effective strategy for enhancing the electrocatalytic performance of CO 2 reduction reactions (CO 2 RR). In this study, CAU-17 MOFs ([Bi(BTC)(H 2 O)]·2 H 2 O·MeOH) were prepared via a sonication-assisted method at room temperature, which is considered a simpler technique compared to the conventional hydrothermal method. Additionally, the morphology of CAU-17 MOFs was further regulated by incorporating a rare-earth metal (La), resulting in the observation of two distinct structures, i.e. CAU-17 hexagonal prism (CAU-17-HP) and CAU-17 layer (CAU-17-Layer). Compared to CAU-17-HP, CAU-17-Layer exhibits an excellent selectivity towards formate with the maximum Faradaic efficiency of 95.5% at − 1.1 V RHE in an H-cell. Subsequently, the limited catalytic activity of CAU-17-Layer was boosted by anchoring nano CeO 2 onto its surfaces (CeO 2 @CAU-17-Layer). The as-prepared composite catalyst demonstrated outstanding performance in the conversion of CO 2 to formate, with a current density surpassing − 100 mA cm-2 at potentials more negative than − 1.0 V RHE and reaching − 200 mA cm-2 at − 1.5 V RHE in a flow cell. This study demonstrates the significant potential of morphology-engineered and rare-earth metals composited MOFs in facilitating highly efficient reduction of CO 2. • Bismuth-based metal-organic frameworks (CAU-17 MOFs) were prepared via a sonication-assisted method at room temperature. • The morphology of CAU-17 MOFs was regulated by rare-earth metal (La). • Morphology engineering boosted the catalytic performance of CAU-17-MOFs. • When incorporating nano-CeO 2 into CAU-17-Layer, the current density reached − 200 mA cm-2 at − 1.5 V RHE. [ABSTRACT FROM AUTHOR]

The preparation of copper matrix composites with high graphene content is difficult, facing the problem of graphene agglomeration. This study proposed a layer-by-layer electrodeposition method to obtain the reduced graphene oxide/copper (RGO/Cu) composite with a layered structure. It was found that the layered distribution of RGO avoided the occurrence of agglomeration effectively, which was conducive to the excellent mechanical strength and toughness of the composite. The strength of the RGO/Cu composite increased with the number of layers, and the tensile strength of the 29-layer composite was 34.2 % higher than that of pure copper. While, its elongation remained at the same level as that of pure copper. The toughening and strengthening mechanism of layered RGO in the composite was analyzed by molecular dynamics simulation. Confinement on crack propagation and strain energy consumption by sliding of layered RGO were identified as the reason for maintaining the high toughness of the composite, and stress transfer, grain refinement and dislocation strengthening were contributed to the high tensile strength. • RGO/Cu composite with a layered structure was prepared by layer-by-layer electrodeposition. • Compared with pure copper, the tensile strength of 29-layer RGO/Cu increased by 34.2 %, while the toughness remained unchanged. • The toughening and strengthening mechanism of layered RGO in the composite was analyzed by molecular dynamics. [ABSTRACT FROM AUTHOR]

Nickel alloy 690 (Ni690) were fabricated by wire arc additive manufacturing (WAAM) with three kinds of TiC particles adding contents (no TiC addition, 0.5 wt% TiC, 1.0 wt% TiC) based on cold metal transfer (CMT) technology. The effects of TiC particles adding content on the microstructure, mechanical properties and corrosion resistance were investigated. After adding 1.0 wt% TiC particles, the average length of the γ grains decreased from 301 ± 61 µm to 114 ± 15 µm and the structure of grains changed from columnar dendrite into equiaxed dendritic at the top of each layer, which is results of the heterogeneous nucleation and increase of constitutional supercooling caused by TiC particles. The difference between horizontal and vertical mechanical properties of WAAM Ni690 component disappeared because the heterogeneous nucleation caused by TiC particles prevented the epitaxial growth. The ultimate tensile strength of the WAAM 1.0TiC-Ni690 component reached 590 MPa in both directions, which increased 10 % compared with no TiC addition. The improvement of mechanical properties was owing to the grain refinement and the formation of reinforcing TiC/(Ti, Nb)C second-phase particles. The potentiodynamic polarization tests showed that the improved corrosion resistance with the increased content of TiC particles. The electrochemical impedance spectroscopy (EIS) tests results showed that due to the refined γ columnar grains providing more nucleation sites, a denser and thicker passive film was formed, which improved the corrosion resistance. The composition of the passive film was analyzed by X-ray photoelectron spectroscopy (XPS). The results reflected the more content of oxides and hydroxides of Cr in the passive film of WAAM 1.0TiC-Ni690 sample represented the denser passive film and better corrosion resistance. • Nickel alloy 690 (Ni690) were fabricated by wire arc additive manufacturing (WAAM) with different kinds of TiC particles adding contents. The TiC particles improved the mechanical properties and corrosion resistance • With the addition of TiC particles, the anisotropy in strength of WAAM Ni690 component disappeared for heterogeneous nucleation and the reinforcing TiC/(Ti, Nb)C particles improved the strength of WAAM 1.0TiC-Ni690 component in both directions reaching 590 MPa. • The refiner columnar γ grains offered more nucleation sites on the grain boundaries for the formation of thicker passive film. The more content of oxides and hydroxides of Cr in the passive film of WAAM 1.0TiC-Ni690 component represented the denser passive film and better corrosion resistance. [ABSTRACT FROM AUTHOR]