Proton exchange membrane fuel cells (PEMFCs) with high efficiency and nonpollution characteristics have attracted massive attention from both academic and industrial communities due to their ...irreplaceable roles in building the future sustainable energy system. However, the stability issue of Pt‐based catalysts for oxygen reduction reaction (ORR) has become a central constraint to the widespread deployment of the devices relative to the catalytic activity. This review aims to provide comprehensive insights into how to improve the stability of Pt‐based catalysts for ORR. First, the basic physical chemistry behind the catalyst degradation, including the fundamental understandings of carbon corrosion, catalyst dissolution, and particle sintering, is highlighted. After a discussion of advanced characterization techniques for the catalyst degradation, the design strategies for improving the stability of Pt‐based catalysts are summarized. Finally, further insights into the remaining challenges and future research directions are also provided.
Strategies to improve the stability of Pt‐based catalysts for the oxygen reduction reaction are comprehensively reviewed. The basic physical chemistry behind the catalyst degradation is highlighted. After a discussion of advanced characterization techniques for the catalyst degradation, design strategies for improving the stability of Pt‐based catalysts are proposed.
► Diversity of endophytic bacterial populations in Solanum nigrum L. was analyzed. ► The 16S rDNA clone library was diversiform and dominated by α-Proteobacteria. ► Some dominated genera may play an ...important role in heavy-metal stress reduction.
Despite the broad application of molecular approaches for the analysis of bacterial communities in a wide range of natural habitats, little information is available on the diversity of bacterial endophytes in the hyperaccumulators growing in heavy-metal contaminated sites. In this study, the diversity of bacterial endophytes associated with Cd-hyperaccumulator Solanum nigrum L. growing in mine tailing was analyzed by 16S rDNA clone library technique. In total, 197 individual sequences comprising 40 different Operational Taxonomic Units (OTUs) were used to assess the diversity of bacterial endophytes. Phylogenetic analysis revealed that the majority of clones were affiliated with Proteobacteria (61.93%; 19 OTUs), which included α (41.12%; 11 OTUs), β (6.09%; 4 OTUs) and γ (14.72%; 4 OTUs) subclasses. Other clones belonged to Bacteroidetes (12.18%; 5 OTUs), Firmicutes (2.03%; 2 OTUs), Actinobacteria (18.78%; 10 OTUs) and uncultured bacteria (5.08%; 4 OTUs). The dominant genera were Sphingomonas and Pseudomonas, which accounted for 24.37% and 12.18% of total clones respectively. These findings suggested that the diversity of endophytic bacterial populations was abundant in S. nigrum L., and these bacterial endophytes should be targeted for future research to determine their functional role, if any, in heavy metal stress reduction.
The lack of highly efficient catalysts severely hinders large‐scale application of electrochemical hydrogen evolution reaction (HER) for hydrogen production from water. Herein, synergistic cascade ...hydrogen evolution boosting by combining the strategies of carbon layer confinement and surface oxophilicity modification is realized. The carbon layers confined ultrafine RuCr nanoparticles (RuCr@C) exhibit outstanding HER activity (j10 = 19 mV, turnover frequency = 4.25 H2 s‐1), surpassing the benchmark Pt/C and most of the reported HER catalysts. Combined experimental verifications and theoretical simulations reveal that surface adsorption modification and electronic structure regulation synergistically boosts the HER kinetics over the RuCr@C catalyst. The Volmer step is accelerated by stabilizing the final state of water dissociation (*H and *OH) through Cr doping, and the Heyrovsky step is promoted via carbon layers confinement. As such, this work highlights a synergistic cascade strategy to boost HER kinetics which is of fundamental importance to accelerate future advances in electrocatalysis.
A synergistic cascade strategy is employed to boost hydrogen evolution via combining carbon layer confinement and surface oxophilicity modification. The as crafted RuCr nanoparticles confined in carbon layers exhibit outstanding hydrogen evolution reaction (HER) activity (j10 = 19 mV, turnover frequency = 4.25 H2 s−1), surpassing the benchmark Pt/C and most of the reported HER catalysts.
Modulating the local coordination structure of metal single-atom catalysts (SACs) is extensively employed to tune the catalytic activity, but rarely involved in regulating the reaction pathway which ...fundamentally determines the product selectivity. Herein, we report that the product selectivity of electrochemical CO
2
reduction (CO
2
RR) on the single-atom indium-N
x
C
4−
x
(1 ≤
x
≤ 4) catalysts could be tuned from formate to CO by varying the carbon and nitrogen occupations in the first coordination sphere. Surprisingly, the optimal In SAC showed great promise for CO production with the maximum Faradic efficiency of 97%, greatly different from the reported In-based catalysts where the formate is the dominant product. Combined experimental verifications and theoretical simulations reveal that the selectivity switch from formate to CO on In SACs originates from active sites shift from indium center to the indium-adjacent carbon atom, where the indium site favors formate formation and the indium-adjacent carbon site prefers the CO pathway. The present work suggests the active sites in metal SACs may shift from the widely accepted metal center to surrounding carbon atoms, thereby offering a new implication to revisit the active sites for metal SACs.
1Selective electroreduction of carbon dioxide (CO2RR) into ethanol at an industrially relevant current density is highly desired. However, it is challenging because the competing ethylene production ...pathway is generally more thermodynamically favored. Herein, we achieve a selective and productive ethanol production over a porous CuO catalyst that presents a high ethanol Faradaic efficiency (FE) of 44.1 ± 1.0% and an ethanol-to-ethylene ratio of 1.2 at a large ethanol partial current density of 501.0 ± 15.0 mA cm−2, in addition to an extraordinary FE of 90.6 ± 3.4% for multicarbon products. Intriguingly, we found a volcano-shaped relationship between ethanol selectivity and nanocavity size of porous CuO catalyst in the range of 0 to 20 nm. Mechanistic studies indicate that the increased coverage of surface-bounded hydroxyl species (*OH) associated with the nanocavity size-dependent confinement effect contributes to the remarkable ethanol selectivity, which preferentially favors the *CHCOH hydrogenation to *CHCHOH (ethanol pathway) via yielding the noncovalent interaction. Our findings provide insights in favoring the ethanol formation pathway, which paves the path toward rational design of ethanol-oriented catalysts.
Selective electroreduction of carbon dioxide (CO
RR) into ethanol at an industrially relevant current density is highly desired. However, it is challenging because the competing ethylene production ...pathway is generally more thermodynamically favored. Herein, we achieve a selective and productive ethanol production over a porous CuO catalyst that presents a high ethanol Faradaic efficiency (FE) of 44.1 ± 1.0% and an ethanol-to-ethylene ratio of 1.2 at a large ethanol partial current density of 501.0 ± 15.0 mA cm
, in addition to an extraordinary FE of 90.6 ± 3.4% for multicarbon products. Intriguingly, we found a volcano-shaped relationship between ethanol selectivity and nanocavity size of porous CuO catalyst in the range of 0 to 20 nm. Mechanistic studies indicate that the increased coverage of surface-bounded hydroxyl species (*OH) associated with the nanocavity size-dependent confinement effect contributes to the remarkable ethanol selectivity, which preferentially favors the *CHCOH hydrogenation to *CHCHOH (ethanol pathway) via yielding the noncovalent interaction. Our findings provide insights in favoring the ethanol formation pathway, which paves the path toward rational design of ethanol-oriented catalysts.
* Stripe rust caused substantial yield losses in China. * P. striiformis is highly variable and the change from avirulence to virulence. * Different comprehensive control strategies were adopted in ...different epidemic region.
Stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici occurs in almost all wheat-producing regions of the world. Severe countrywide epidemics in China have caused substantial yield losses. Growing resistant cultivars is the best strategy to control this disease but the pathogen can overcome resistance in wheat cultivars. The high variation in the virulence of the pathogen combined with the large areas of susceptible wheat cultivars enables the pathogen population to increase rapidly and disperse over long distances under favorable environmental conditions, resulting in severe pandemics within cropping seasons. Current stripe rust control measures are based on many years of research including the underlying epidemiology regarding year-to-year survival of the pathogen, pathways of pathogen dispersal within seasons and years, the role of P. striiformis sexual hybridization, the use of resistance sources in breeding programs, and year-round surveillance of national wheat crops that are present in different parts of the country throughout the year. All these strategies depend on accurate prediction of epidemics, more precise use of fungicides to meet national requirements and better deployment of resistance genes. New ideas with potential application in sustainable protection of stripe rust include negative regulatory gene editing, resistance gene overexpression and biological control based on microbiomes.
A graphene nanosheet/ultra-high molecular weight polyethylene composite with a segregated structure has been fabricated using water/ethanol solvent-assisted dispersion and hot compression at 200
°C. ...A percolation threshold as low as 0.070
vol.% has been achieved because of the formation of a two-dimensional conductive network.
Stripe rust caused by
Puccinia striiformis
f. sp
. tritici
(
Pst
) is one the most important diseases of wheat in Ethiopia and worldwide. To identify resistance genes, 90 bread wheat lines and 10 ...cultivars were tested at the seedling stage against one
Pst
race from Ethiopia and six races from China as well as evaluated for the stripe rust response in an inoculated field nursery at Yangling, Shaanxi province and in a naturally infected field in Jiangyou, Sichuan, China. Resistance genes were postulated using molecular assays for
Yr9
,
Yr17, Yr18, Yr26, Yr29, Yr36, Yr44
and
Yr62.
Of the 100 entries tested, 16 had all stage resistance to all races. Molecular markers were positive for
Yr9
in five genotypes,
Yr17
in 21 genotypes,
Yr18
in 27 genotypes,
Yr26
in ten genotypes,
Yr29
in 22 genotypes,
Yr36
in 12 genotypes,
Yr44
in 30 genotypes, and
Yr62
in 51 genotypes. No line had
Yr5
,
Yr8
,
Yr10
or
Yr15
. Complete or all stage resistance was observed in genotypes carrying gene combinations
Yr9
+
Yr18
+
Yr44
+
Yr62, Yr29
+
Yr62
+
Yr26
and
Yr9
+
Yr17
+
Yr26
+
Yr44
+
Yr62.
The results are helpful for developing wheat cultivars with effective and more durable resistance to stripe rust both in China and Ethiopia.
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