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High-temperature proton exchange membrane fuel cells (HT-PEMFCs) bring new opportunities for portable power generation due to their outstanding advantages such as high tolerance to fuel/air impurities and simplified heat/water management. However, carbon-supported nanostructured Pt-based catalysts running at temperatures over 150°C are challenged by the severe aggregation and carbon corrosion, thus leading to poor durability. Herein, we demonstrate that dendritic Pt-Ni nanoparticles supported on fluorinated carbon black (white carbon black) could significantly enhance the performance and durability of HT-PEMFCs as the cathode catalysts running at 160°C due to the strong interaction of the F and Ni atoms to form a NixFy interface on Pt-Ni nanoparticles. With the formation of a stable NixFy interface, this integrated HT-PEMFC reached peak power densities of 906 mW cm−2 and demonstrated excellent durability at 160°C under anhydrous H2/O2 conditions. This mitigation strategy was applied to Pt-alloy/C electrocatalysts and resulted in the elimination of Pt dissolution in practical fuel cells.

High-entropy alloys (HEAs) have been widely studied due to their unconventional compositions and unique physicochemical properties for various applications. Herein, for the first time, we propose a surface strain strategy to tune the electrocatalytic activity of HEAs for methanol oxidation reaction (MOR). High-resolution aberration-corrected scanning transmission electron microscopy (STEM) and elemental mapping demonstrate both uniform atomic dispersion and the formation of a face-centered cubic (FCC) crystalline structure in PtFeCoNiCu HEAs. The HEAs obtained by heat treatment at 700°C (HEA-700) exhibit 0.94% compressive strain compared with that obtained at 400°C (HEA-400). As expected, the specific activity and mass activity of HEA-700 is higher than that of HEA-400 and most of the state-of-the-art catalysts. The enhanced MOR activity can be attributed to a shorter Pt-Pt bond distance in HEA-700 resulting from compressive strain. The nonprecious metal atoms in the core could generate compressive strain and down shift d-band centers via electron transfer to surface Pt layer. This work presents a new perspective for the design of high-performance HEAs electrocatalysts.

Analyses of the physiology and pathology of active biochemical species in their native contexts are critical for early diagnosis and therapy. Optical imaging has emerged as one of the promising modalities for noninvasive and real-time visualization of important biomolecules or biological events, and it has witnessed major advances in the field of imaging in vitro and in vivo . In this review, we present a survey of common approaches and tactics for enhanced targetability, response rate, and photostability in bioimaging applications. Recently developed and representative examples are illustrated on the cellular and tissue levels.