To improve the interfacial mass-transfer
efficiency, microporous
layers (MPLs) containing CeO2 nanorods and the CeO2 nano-network were prepared for proton exchange membrane fuel
cells (PEMFCs). In order to minimize the contact resistance, the three-dimensional
(3D) graphene foam (3D-GF) was used as the carrier for the deposition
of CeO2 nanorods and the nano-network. The CeO2-doped 3D-GF anchored at the interface between the catalyst layer
and microporous layer manufactured several novel functional protrusions.
To evaluate the electrochemical property, the normal MPL, the MPL
containing raw 3D-GF, and MPLs containing different kinds of CeO2-doped 3D-GF were used to assemble the membrane electrode
assemblies (MEAs). Measurements show that the CeO2-doped
3D-GF improved the reaction kinetics of the cathode effectively. In
addition, the hydrophilic CeO2-doped 3D-GF worked as the
water receiver to prevent the dehydration of MEAs at dry operating
condition. Besides, at a high current density or humid operating condition,
the CeO2-doped 3D-GF provided the pathway for water removal.
Compared with the CeO2 nanorods, the CeO2 nano-network
on 3D-GF revealed a higher adaptability at varying operating conditions.
Hence, such composition and structure design of MPL is a promising
strategy for the optimization of high-performance PEMFCs.
Recently, endorhizospheric microbiota is realized to be able to promote the secondary metabolism in medicinal plants, but the detailed metabolic regulation metabolisms and whether the promotion is influenced by environmental factors are unclear yet. Here, the major flavonoids and endophytic bacterial communities in various Glycyrrhiza uralensis Fisch. roots collected from seven distinct places in northwest China, as well as the edaphic conditions, were characterized and analyzed. It was found that the soil moisture and temperature might modulate the secondary metabolism in G. uralensis roots partially through some endophytes. One rationally isolated endophyte Rhizobium rhizolycopersici GUH21 was proved to promote the accumulation of isoliquiritin and glycyrrhizic acid significantly in roots of the potted G. uralensis under the relatively high-level watering and low temperature. Furthermore, we did the comparative transcriptome analysis of G. uralensis seedling roots in different treatments to investigate the detailed mechanisms of the environment-endophyte-plant interactions and found that the low temperature went hand in hand with the high-level watering to activate the aglycone biosynthesis in G. uralensis, while GUH21 and the high-level watering cooperatively promoted the in planta glucosyl unit production. Our study is of significance for the development of methods to rationally promote the medicinal plant quality.
Key points
• Soil temperature and moisture related to isoliquiritin contents in Glycyrrhiza uralensis Fisch.
• Soil temperature and moisture related to the hosts’ endophytic bacterial community structures.
• The causal relation among abiotic factors—endophytes—host was proved through the pot experiment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.