Bimetallic metal–organic frameworks are rationally synthesized as templates and employed for porous carbons with retained morphology, high graphitization degree, hierarchical porosity, high surface ...area, CoNx moiety and uniform N/Co dopant by pyrolysis. The optimized carbon with additional phosphorus dopant exhibits excellent electrocatalytic performance for the oxygen reduction reaction, which is much better than the benchmark Pt/C in alkaline media.
Exploring low‐cost and high‐performance nonprecious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) in fuel cells and metal–air batteries is crucial for the commercialization of these ...energy conversion and storage devices. Here we report a novel NPMC consisting of Fe3C nanoparticles encapsulated in mesoporous Fe‐N‐doped carbon nanofibers, which is synthesized by a cost‐effective method using carbonaceous nanofibers, pyrrole, and FeCl3 as precursors. The electrocatalyst exhibits outstanding ORR activity (onset potential of −0.02 V and half‐wave potential of −0.140 V) closely comparable to the state‐of‐the‐art Pt/C catalyst in alkaline media, and good ORR activity in acidic media, which is among the highest reported activities of NPMCs.
Nanocomposite electrocatalyst: A high‐performance electrocatalyst for the oxygen reduction reaction (ORR) is based on Fe3C nanoparticles encapsulated in mesoporous Fe‐N‐doped carbon nanofibers. It can be synthesized from low‐cost and abundant precursors and exhibits excellent electrocatalytic performance for the ORR in both alkaline and acidic media.
Thirsty fibers: The aerogels described in the title can be fabricated in large scale by using a low‐cost biomass, bacterial cellulose, as a precursor, which can be produced at industrial level in a ...microbial fermentation process. The carbon nanofiber aerogels (black pieces in picture) exhibit superior absorption capacity for organic solvents (red solution) and high potential for pressure sensing.
Electrochemically converting nitrate, a widespread water pollutant, back to valuable ammonia is a green and delocalized route for ammonia synthesis, and can be an appealing and supplementary ...alternative to the Haber-Bosch process. However, as there are other nitrate reduction pathways present, selectively guiding the reaction pathway towards ammonia is currently challenged by the lack of efficient catalysts. Here we report a selective and active nitrate reduction to ammonia on Fe single atom catalyst, with a maximal ammonia Faradaic efficiency of ~ 75% and a yield rate of up to ~ 20,000 μg h
mg
(0.46 mmol h
cm
). Our Fe single atom catalyst can effectively prevent the N-N coupling step required for N
due to the lack of neighboring metal sites, promoting ammonia product selectivity. Density functional theory calculations reveal the reaction mechanisms and the potential limiting steps for nitrate reduction on atomically dispersed Fe sites.
Abstract
Oxygen reduction reaction towards hydrogen peroxide (H
2
O
2
) provides a green alternative route for H
2
O
2
production, but it lacks efficient catalysts to achieve high selectivity and ...activity simultaneously under industrial-relevant production rates. Here we report a boron-doped carbon (B-C) catalyst which can overcome this activity-selectivity dilemma. Compared to the state-of-the-art oxidized carbon catalyst, B-C catalyst presents enhanced activity (saving more than 210 mV overpotential) under industrial-relevant currents (up to 300 mA cm
−2
) while maintaining high H
2
O
2
selectivity (85–90%). Density-functional theory calculations reveal that the boron dopant site is responsible for high H
2
O
2
activity and selectivity due to low thermodynamic and kinetic barriers. Employed in our porous solid electrolyte reactor, the B-C catalyst demonstrates a direct and continuous generation of pure H
2
O
2
solutions with high selectivity (up to 95%) and high H
2
O
2
partial currents (up to ~400 mA cm
−2
), illustrating the catalyst’s great potential for practical applications in the future.
The electrochemical synthesis of chemicals and fuel feedstocks has been demonstrated to be a sustainable and “green” alternative to traditional chemical engineering, where oxygen evolution reaction ...(OER) plays a vital role in coupling with various cathodic reactions. While tremendous attention, involving both research and review topics, has been focused on pushing the limit of OER catalysts’ activity, the long-term stability of OER catalysts, which may play an even more important role in large-scale electrolysis industrialization, has been much less emphasized. Until this point, few systematic strategies for developing OER catalysts with industrially relevant durability have been reported. In this review, critical mechanisms that could influence OER stability are summarized, including surface reconstruction, lattice oxygen evolution, and the dissolution-redeposition process of catalysts. Moreover, to bridge the gap between lab-scale OER tests and large-scale electrocatalysis applications, stability considerations in electrolyzer design for long-term operation are also discussed in detail. This review provides catalyst and reactor design principles for overcoming OER stability challenges and will focus more attention from the field on the great importance of OER stability as well as future large-scale electrocatalysis applications.
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Recently, clean energy conversion through electrocatalysis is evolving rapidly as a promising alternative to fossil-fuel energy systems. However, electrolyzers have always suffered from long-term stability challenges, especially for the anodic oxygen evolution reaction catalysts. So far, other than high-cost noble-metal catalysts such as IrO2, no catalysts with industrially relevant stability for oxygen evolution process in acidic and neutral conditions have been demonstrated. Thus, mechanisms that lead to catalytic instability require further investigation and deep understanding to guide future catalyst design.
In order to explore both the origins of and solutions to the stability challenges, this review provides a comprehensive overview and analysis on mechanistic studies of OER catalytic stability. Surface reconstruction of catalysts under oxidation potential during oxygen evolution is one of the causes of catalyst degradation. In addition, lattice oxygen can sometimes participate in the reaction pathway and induce structural instability of catalysts. In addition, redeposition of dissolved ions onto the catalyst surface is a process that gains less attention but can greatly influence the catalytic stability. Besides the catalyst consideration, critical elements of electrolyzers are also discussed in this review to provide insights in electrolysis operation under more realistic conditions. Based on the studies summarized in this article, we also provide potential strategies to design stable OER catalysts. By appropriately tuning the components, structures, dissolution, and redeposition rates of catalysts, we believe that the development of catalysts with long-term stability for oxygen evolution reaction can be achieved in the near future.
Oxygen evolution reaction (OER) plays a vital role in clean energy conversion through electrochemical synthesis of chemicals and fuel feedstocks. However, OER catalysts have always suffered from long-term stability challenges. This review timely summarizes critical reaction mechanisms that could influence OER stability, discusses stability considerations for reactor designs, and proposes future perspectives and potential strategies for designing stable OER catalysts to overcome these challenges.
Sunitinib resistance is a major challenge for advanced renal cell carcinoma (RCC). Understanding the underlying mechanisms and developing effective strategies against sunitinib resistance are highly ...desired in the clinic. Here we identified an lncRNA, named lncARSR (lncRNA Activated in RCC with Sunitinib Resistance), which correlated with clinically poor sunitinib response. lncARSR promoted sunitinib resistance via competitively binding miR-34/miR-449 to facilitate AXL and c-MET expression in RCC cells. Furthermore, bioactive lncARSR could be incorporated into exosomes and transmitted to sensitive cells, thus disseminating sunitinib resistance. Treatment of sunitinib-resistant RCC with locked nucleic acids targeting lncARSR or an AXL/c-MET inhibitor restored sunitinib response. Therefore, lncARSR may serve as a predictor and a potential therapeutic target for sunitinib resistance.
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•lncARSR promotes sunitinib resistance and predicts poor response of RCC patients•Intercellular transfer of lncARSR by exosomes disseminates sunitinib resistance•lncARSR acts as a ceRNA for miR-34 and miR-449 to promote AXL and c-MET expression•Targeting lncARSR or AXL/c-MET in sunitinib-resistant RCC restores drug sensitivity
Qu et al. identify lncARSR as a mediator of sunitinib resistance in renal cell carcinoma by acting as a competing endogenous RNA for miR-34 and miR-449, thereby increasing expression of their targets AXL and c-MET, and show that exosome-mediated transmission of lncARSR can confer resistance to sensitive cells.
Carbon aerogels with 3D networks of interconnected nanometer‐sized particles exhibit fascinating physical properties and show great application potential. Efficient and sustainable methods are ...required to produce high‐performance carbon aerogels on a large scale to boost their practical applications. An economical and sustainable method is now developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels from the wood‐based nanofibrillated cellulose (NFC) aerogels via a catalytic pyrolysis process, which guarantees high carbon residual and well maintenance of the nanofibrous morphology during thermal decomposition of the NFC aerogels. The wood‐derived CNF aerogels exhibit excellent electrical conductivity, a large surface area, and potential as a binder‐free electrode material for supercapacitors. The results suggest great promise in developing new families of carbon aerogels based on the controlled pyrolysis of economical and sustainable nanostructured precursors.
Nano‐woodwork: An economical and sustainable method has now been developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels by engineering the thermal decomposition chemistry of nanofibrillated wood cellulose. This work suggests great promise in developing new families of carbon aerogels based on the controlled pyrolysis of sustainable nanostructured precursors.
Electrochemical oxygen reduction to hydrogen peroxide (H
O
) in acidic media, especially in proton exchange membrane (PEM) electrode assembly reactors, suffers from low selectivity and the lack of ...low-cost catalysts. Here we present a cation-regulated interfacial engineering approach to promote the H
O
selectivity (over 80%) under industrial-relevant generation rates (over 400 mA cm
) in strong acidic media using just carbon black catalyst and a small number of alkali metal cations, representing a 25-fold improvement compared to that without cation additives. Our density functional theory simulation suggests a "shielding effect" of alkali metal cations which squeeze away the catalyst/electrolyte interfacial protons and thus prevent further reduction of generated H
O
to water. A double-PEM solid electrolyte reactor was further developed to realize a continuous, selective (∼90%) and stable (over 500 hours) generation of H
O
via implementing this cation effect for practical applications.
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