Hsin-Yu Chen

Copper nanowires with fivefold twinned structures (t-CuNWs) are shown to be effective as cathode catalysts for the electrochemical reduction of CO₂ (CO₂RR) in a zero-gap electrolyzer to produce ethylene.

This study investigates copper nanowires with fivefold twinned structures (t-CuNWs) as catalysts for the electrochemical reduction of CO2 (CO2RR) in a zero-gap flow cell with 1 M KOH as anolyte. The t-CuNWs, with surfaces enclosed by (100) facets, were selected for their enhanced CO adsorption strength, which promotes C–C coupling—a key pathway toward multi-carbon (C2+) products. Additionally, the entangled t-CuNWs exhibits enhanced hydrophobicity when compared to commercial Cu nanoparticles (CuNPs), which can reduce flooding issues and contribute to high stability during electrochemical operation. These characteristics distinguish t-CuNWs from CuNPs in terms of activity and stability. The t-CuNWs exhibited ~ 40% C2H4 faradic efficiency (FE) for more than 4 hours under a current density of 100 mA/cm2, while commercial CuNPs exhibited ~ 20% C2H4 FE for less than 4 hours under the same condition. These findings highlight the potential of (100) faceted t-CuNWs for efficient and durable C2+ product formation in CO2RR with facet engineering and hydrophobicity control.

Nanotwinned copper (nt-Cu) has proven to possess many fascinating physical/chemical properties. However, it is still challenging to control the twin density and its orientation especially for high aspect-ratio Cu vias. Here, a matrix of nt-Cu nanowires (aspect ratio > 150) with dense coherent twin boundaries (CTBs) perpendicular to the growth direction were deposited in porous anodic aluminium oxide vias by pulse electrodeposition. We changed the pulse on/off duration to control the degree of (111) growth texture and twin density of the nt-Cu nanowires. A small anodic current in the pulse-off period enhanced (111) crystal texture and CTB formation during the bottom-up filling process. With the analysis of twin density, we proposed that the nanoscale twinning was activated by facet-dependent crystal growth and stress accumulation/relaxation behaviour during pulse electrodeposition. The interplay between on/off period and bias potential could modulate the twin density. Also, the sulfate adsorbates were proved to play an important role in the stress accumulation process. This study could be implemented in fabricating Cu interconnect in nanoelectronic devices and nanoelectromechanical systems. Figure 1

In this study, post-CF₄ plasma surface treatment of light addressable potentiometric sensor (LAPS) with a HfO₂-sensing membrane was carried out. pH sensitivity decreased but pNa sensitivity increased with fluorine incorporation. The highest pNa sensitivity was 31.8 mV/pNa, which was optimized with 3 min post CF₄ plasma treatment. The results showed a high possibility for sensing sodium ions using an inorganic-sensing membrane and a fabrication process. Moreover, on the basis of the analysis of atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) spectra, a sensing mechanism was developed.