Electrodeposition-fabricated PtCu-alloy cathode catalysts for high-temperature proton exchange membrane fuel cells

Enhanced phosphoric acid tolerance and intrinsic activity of ordered platinum-zinc alloy catalysts for oxygen reduction reaction

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) offer significant advantages in energy conversion efficiency but face severe challenges from phosphoric acid (PA) poisoning, which deactivates platinum (Pt)-based oxygen reduction reaction (ORR) catalysts. This study presents a dual strategy combining structural ordering and electrochemical potential cycling to enhance the intrinsic catalytic activity and PA tolerance of platinum-zinc (PtZn) alloy catalysts. Ordered PtZn (L10-PtZn) alloy electrocatalysts synthesized through thermal annealing demonstrated enhanced ORR performance, achieving a mass activity of 0.42 A mg-1Pt, surpassing the A1-PtZn (0.28 A·mg-1Pt) and commercial Pt/C electrocatalysts (0.17 A·mg-1Pt). Transmission electron microscopy (TEM) and X-ray diffraction (XRD) and analyses revealed the structural advantages of L10-PtZn, including optimized lattice strain and reduced surface Zn obstacle. Single-cell tests confirmed its superior power density of 411 mW·cm-2, outperforming disordered alloys and commercial catalysts. Under phosphoric acid exposure, the L10-PtZn catalyst demonstrated exceptional tolerance and exhibiting minimal Pt and Zn dissolution during accelerated degradation tests. The remarkable stability and enhanced activity are attributed to the inherent atomic ordering and surface reconstruction mechanisms of L10-PtZn. These findings underscore the potential of ordered PtZn alloys as next-generation cathode catalysts for HT-PEMFCs, addressing critical challenges of PA tolerance and long-term stability.

Research Progress in Energy Based on Polyphosphazene Materials in the Past Ten Years

With the rapid development of electronic devices, the corresponding energy storage equipment has also been continuously developed. As important components, including electrodes and diaphragms, in energy storage device and energy storage and conversion devices, they all face huge challenges. Polyphosphazene polymers are widely used in various fields, such as biomedicine, energy storage, etc., due to their unique properties. Due to its unique design variability, adjustable characteristics and high chemical stability, they can solve many related problems of energy storage equipment. They are expected to become a new generation of energy materials. This article briefly introduces the research progress in energy based on polyphosphazene materials in the past ten years, on topics such as fuel cells, solar cells, lithium batteries and supercapacitors, etc. The main focus of this work is on the defects of different types of batteries. Scholars have introduced different functional group modification that solves the corresponding problem, thus increasing the battery performance.

A Combined Study of TEM-EDS/XPS and Molecular Modeling on the Aging of THPP, ZPP, and BKNO3 Explosive Charges in PMDs under Accelerated Aging Conditions

The aging mechanism of explosive charges in pyrotechnic mechanical devices (PMDs) is pre-oxidations of their fuels (TiH2 for THPP, Zr for ZPP, and B for BKNO3) by external oxygen. The effect of water on the aging of explosive charges was thus investigated by TEM-EDS/XPS and DFT-based molecular modeling under accelerated aging with 71 °C and 100% relative humidity. The formation of oxide shell and its thickness on the surface of fuels by the aging were observed by TEM-EDS. It failed to detect any oxide on the surface of TiH2 (no sign of Ti-O peaks in XPS) regardless of the aging time, while the thickness of oxide shell increases linearly with the time for ZPP and is saturated at a certain point for BKNO3. It suggested that THPP is highly robust to aging compared to the others (the order of THPP >> BKNO3 > ZPP). Then, DFT-based vacuum slab calculations visualized the diffusion of oxygen from the surface of fuels into the interior, confirming that the activation barrier for the oxygen diffusion is much lower for Zr and B than TiH2 (37, 107, and 512 kcal/mol for Zr, B, and TiH2, respectively), in agreement with experimental results.