ACS Nanoscience Au最新文献

The development of supercapacitors is pivotal for sustainable energy storage solutions, necessitating the advancement of innovative electrode materials to supplant fossil-fuel-based energy sources. Zinc oxide (ZnO) is widely studied for use in supercapacitor electrodes because of its beneficial physicochemical properties, including excellent chemical and thermal stability, semiconducting characteristics, low cost, and environmentally friendly nature. In this study, ZnO nanorods were synthesized using a simple hydrothermal method and then combined with various Ni-based layered double hydroxides (LDHs) [NiM′-LDHs (M′ = Mn, Co, and Fe)] to improve the electrochemical performance of the ZnO nanorods. These LDHs are well-known for their outstanding electrochemical and electronic properties, high specific capacitance, and efficient dispersion of cations within host nanolayers. The synthesized composites ZnO@NiMn-LDH, ZnO@NiCo-LDH, and ZnO@NiFe-LDH exhibit enhanced specific capacitances of 569.3, 284.6, and 133.0 F/g, respectively, at a current rate of 1 A/g, outperforming bare ZnO (98.4 F/g). Notably, ZnO@NiMn-LDH demonstrates superior electrochemical performance along with a capacitance retention of 76%, compared to ZnO@NiCo-LDH (58%), ZnO@NiFe-LDH (49%), and bare ZnO (23%) over 5000 cycles. Furthermore, an asymmetric supercapacitor (ASC) was developed by using ZnO@NiMn-LDH as the positive electrode and activated carbon (AC) as the negative electrode to assess its practical applicability. The fabricated ASC (ZnO@NiMn-LDH//AC) demonstrated a specific capacitance of 45.22 F/g at a current rate of 1 A/g, an energy density of 16.08 W h/kg at a power density of 798.8 W/kg, and a capacitance retention of 75% over 5000 cycles. These findings underscore the potential of the composite formation of ZnO with Ni-based LDHs in advancing the efficiency and durability of supercapacitors.

Acidic oxygen evolution reaction (OER) has long been the bottleneck of proton exchange membrane water electrolysis. Ru- and Ir-based oxides are currently state-of-the-art electrocatalysts for acidic OER, but their high cost limits their widespread application. Co₃O₄ is a promising alternative, yet the performance requires further improvement. Crystal facet engineering can effectively regulate the kinetics of surface electrochemistry and thus enhance the OER performance. However, the facet-dependent OER activity and corrosion behavior of Co₃O₄ have not been thoroughly studied. In this study, we systematically investigated the OER performance and crystal facet dependency of Co₃O₄. The results demonstrate that Co₃O₄ with mixed {111} and {110} facets exhibits better OER activity and stability than Co₃O₄ with {111} or {100} facets. The surface Co³⁺ species are responsible for the high OER activity, but its transformation to CoO₂ is also the root cause of the dissolution, leading to an activity–stability trade-off effect. The possible approach to addressing this issue would be to increase the Co³⁺ contents by nanostructure engineering. To further improve the performance, Ru is introduced to the best-performing Co₃O₄. The resulting Co₃O₄/RuO₂ heterostructure exhibits an overpotential of 257 mV at 10 mA cm^–2 and can stably catalyze the OER for 100 h.

Herein, we present a strategy for the controlled assembly of single-walled carbon nanotube (SWCNT) linear junctions mediated by DNA as a functional linker. We demonstrate this by employing SWCNTs of two different chiralities via the specific design of DNA sequences and chiral selection. Streptavidin and AuNP labeling of the SWCNT sidewalls demonstrate the presence of two different chirality within each individual CNT–DNA–CNT junction. These one-dimensional nanohybrids were further organized from solution to devices. The approach we developed is of general applicability for the assembly of functional nanohybrids based on carbon nanotubes toward functional applications.