Linearly Interlinked Fe-Nx-Fe Single Atoms Catalyze High-Rate Sodium-Sulfur Batteries.

Linearly interlinked single atoms offer unprecedented physiochemical properties, but their synthesis for practical applications still poses significant challenges. Herein, linearly interlinked iron single-atom catalysts that are loaded onto interconnected carbon channels as cathodic sulfur hosts for room-temperature sodium-sulfur batteries are presented. The interlinked iron single-atom exhibits unique metallic iron bonds that facilitate the transfer of electrons to the sulfur cathode, thereby accelerating the reaction kinetics. Additionally, the columnated and interlinked carbon channels ensure rapid Na+ diffusion kinetics to support high-rate battery reactions. By combining the iron atomic chains and the topological carbon channels, the resulting sulfur cathodes demonstrate effective high-rate conversion performance while maintaining excellent stability. Remarkably, even after 5000 cycles at a current density of 10 A g-1, the Na-S battery retains a capacity of 325 mAh g-1. This work can open a new avenue in the design of catalysts and carbon ionic channels, paving the way to achieve sustainable and high-performance energy devices.

Cobalt Single Atoms Enabling Efficient Methanol Oxidation Reaction on Platinum Anchored on Nitrogen-Doped Carbon.

Developing efficient platinum (Pt)-based electrocatalysts with high tolerance to CO poisoning for the methanol oxidation reaction is critical for the development of direct methanol fuel cells. In this work, cobalt single atoms are introduced to enhance the electrocatalytic performance of N-doped carbon supported Pt (N-C/Pt) for the methanol oxidation reaction. The cobalt single atoms are believed to play a critical role in accelerating the prompt oxidation of CO to CO2 and minimizing the CO blocking of the adjacent Pt active sites. Benefitting from the synergistic effects among the Co single atoms, the Pt nanoparticles, and the N-doped carbon support, the Co-modified N-C/Pt (Co-N-C/Pt) electrocatalyst simultaneously delivers impressive electrocatalytic activity and durability with lower onset potential and superb CO poisoning resistance as compared to the N-C/Pt and the commercial Pt/C electrocatalysts.

Reversible Modulated Upconversion Luminescence of MoO3:Yb3+,Er3+ Thermochromic Phosphor for Switching Devices.

Reversible modulation of upconversion luminescence induced by the external field stimuli exhibits potential applications in various fields, such as photoswitches, optical sensing, and optical memory devices. Herein, a new MoO3:Yb3+,Er3+ thermochromic phosphor was synthesized via a high-temperature solid-state method, and the reversible color modification of the MoO3:Yb3+,Er3+ phosphor was obtained by alternating the sintering conditions either in a reducing atmosphere or in air. The color of the MoO3:Yb3+,Er3+ phosphor changed from light-yellow to blue under sintering in the reducing atmosphere and returned back after sintering again in air. The influence of reversible thermochromism on the upconversion luminescence of MoO3:Yb3+,Er3+ phosphor was investigated. The MoO3:Yb3+,Er3+ phosphor prepared in air exhibited visible upconversion luminescence, while the MoO3:Yb3+,Er3+ phosphor has no upconversion luminescence after sintering in the reducing atmosphere. This up-conversion luminescence modulation shows excellent reproducibility after several cycles. The thermochromic MoO3:Yb3+,Er3+ phosphor with reversible modulated upconversion luminescence shows great potential for practical applications in optical switches and optoelectronic multifunctional devices.

Phase transformation induced reversible modulation of upconversion luminescence of WO3:Yb3+, Er3+ phosphor for switching devices.

The upconverting luminescence properties of phosphors are dependent on the hosts. In this work, the WO3:Yb3+, Er3+ phosphor was prepared, and the reversible phase transformation from the WO3 to the WO2 was obtained by alternating the sintering in a reducing atmosphere or in air. The influence of reversible phase transformation on the upconversion luminescence was investigated first. The WO3:Yb3+, Er3+ phosphor exhibits the visible upconversion luminescence, while no upconversion luminescence was observed in the WO2:Yb3+, Er3+ phosphor. The reversible modulation of upconversion luminescence of the WO3:Yb3+, Er3+ phosphor retains the excellent reproducibility, exhibiting the potential applications in data storage and optical switches.

Thermomchromic Reaction-Induced Reversible Upconversion Emission Modulation for Switching Devices and Tunable Upconversion Emission Based on Defect Engineering of WO3:Yb3+,Er3+ Phosphor.

Reversible luminescence modulation of upconversion phosphors has the potential applications as photoswitches and optical memory and data storage devices. Previously, the photochromic reaction was extensively used for the realization of reversible luminescence modulation. It is very necessary to develop other approaches such as thermomchromic reaction to obtain the reversible upconversion luminescence modulation. In this work, the WO3:Yb3+,Er3+ phosphors with various colors were prepared at various temperatures, exhibiting tunable upconversion luminescence attributed to the formation of oxygen vacancies in the host. Upon heat treatment in the reducing atmosphere or air, the WO3:Yb3+,Er3+ phosphors show a reversible thermomchromic property. The reversible upconversion luminescence modulation of WO3:Yb3+,Er3+ phosphors was observed based on thermomchromic reaction. Additionally, the upconversion luminescence modulation is maintained after several cycles, indicating its excellent stability. The WO3:Yb3+,Er3+ phosphors with reversible upconversion luminescence and excellent reproducibility have potential applications as the photoswitches and optical memory and data storage devices.