RESUMEN
The most critical challenge for the large-scale commercialization of proton exchange membrane fuel cells (PEMFCs), one of the primary hydrogen energy technologies, is to achieve decent output performance with low usage of platinum (Pt). Currently, the performance of PEMFCs is largely limited by two issues at the catalyst/ionomer interface, specifically, the poisoning of active sites of Pt by sulfonate groups and the extremely sluggish local oxygen transport toward Pt. In the past few years, emerging strategies are derived to tackle these interface problems through materials optimization and innovation. This perspective summarizes the latest advances in this regard, and in the meantime unveils the molecule-level mechanisms behind the materials modulation of interfacial structures. This paper starts with a brief introduction of processes and structures of catalyst/ionomer interfaces, which is followed by a detailed review of progresses in key materials toward interface optimization, including catalysts, ionomers, and additives, with particular emphasis on the role of materials structure in regulating the intermolecular interactions. Finally, the challenges for the application of the established materials and research directions to broaden the material library are highlighted.
RESUMEN
High-entropy alloy nanoparticles (HEA-NPs) show great potential as functional materials1-3. However, thus far, the realized high-entropy alloys have been restricted to palettes of similar elements, which greatly hinders the material design, property optimization and mechanistic exploration for different applications4,5. Herein, we discovered that liquid metal endowing negative mixing enthalpy with other elements could provide a stable thermodynamic condition and act as a desirable dynamic mixing reservoir, thus realizing the synthesis of HEA-NPs with a diverse range of metal elements in mild reaction conditions. The involved elements have a wide range of atomic radii (1.24-1.97 Å) and melting points (303-3,683 K). We also realized the precisely fabricated structures of nanoparticles via mixing enthalpy tuning. Moreover, the real-time conversion process (that is, from liquid metal to crystalline HEA-NPs) is captured in situ, which confirmed a dynamic fission-fusion behaviour during the alloying process.
RESUMEN
Bupleurum L. (Apiaceae) is a perennial and herbal genus, most species of which have high medicinal value. However, few studies have been performed using plastome data in this genus, and the phylogenetic relationships have always been controversial. In this study, the plastid genomes of Bupleurum chinense and Bupleurum commelynoideum were sequenced, and their gene content, order, and structure were counted and analyzed. The only three published Bupleurum species (B. boissieuanum, B. falcatum, and B. latissimum) and other fifteen allied species were selected to conduct a series of comparative and phylogenetic analyses. The genomes of B. chinense and B. commelynoideum were 155,869 and 155,629 bp in length, respectively, both of which had a typical quadripartite structure. The genome length, structure, guanine and cytosine (GC) content, and gene distribution were highly similar to the other three Bupleurum species. The five Bupleurum species had nearly the same codon usages, and eight regions (petN-psbM, rbcL-accD, ccsA-ndhD, trnK(UUU)-rps16, rpl32-trnL(UAG)-ccsA, petA-psbJ, ndhF-rpl32, and trnP(UGG)-psaJ-rpl33) were found to possess relatively higher nucleotide diversity, which may be the promising DNA barcodes in Bupleurum. Phylogenetic analysis revealed that all Bupleurum species clustered into a monophyletic clade with high bootstrap support and diverged after the Chamaesium clade. Overall, our study provides new insights into DNA barcoding and phylogenetic relationship between Bupleurum and its related genera, and will facilitate the population genomics, conservation genetics, and phylogenetics of Bupleurum in Apiaceae.
RESUMEN
Industrially producing H2O2 consumes lots of energy and generates byproducts. For the first time, we demonstrate the non-energy-consuming, self-powered production of H2O2 based on a Zn-air battery with oxygenated carbon electrocatalyst. The battery with power density of 360 W mgeo-2 at a operating voltage of 0.8 V exhibited high H2O2 production rate of 5.93 mol mgeo-2 h-1. By tuning the ratio of the oxygen-containg groups, the origin of the high activity was investigated. Combining the DFT calculations, we found that C-O-C and -CHO contribute more to the H2O2 production compared to other functional groups.
