Efficient C-N coupling in electrocatalytic urea generation on copper carbonate hydroxide electrocatalysts

Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)_2CO_(3))as an efficient CO_(2)NO_(3)RR electrocatalyst with an impressive urea Faradaic efficiency of45.2%±2.1%and a high yield rate of 1564.5±145.2μg h~(-1)mg_(cat)~(-1).More importantly,H_(2) evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu_2(OH)_2CO_(3) by combining the two intermediates,~*COOH and~*NHO.This work demonstrates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO_(2)NO_(3)RR,and provide guidance for rational design of more advanced catalysts.

Superior oxygen electrocatalyst derived from metal organic coordination polymers by instantaneous nucleation and epitaxial growth for rechargeable Li-O_(2) battery

Rechargeable aprotic Li-O_(2)batteries have attractea increasing attention due to their extremely high capacity,and it is very important to design appropriate strategies to synthesize efficient catalysts used as oxygen cathode.In present work,we present an expedient "instantaneous nucleation and epitaxial growth"(INEG) synthesis strategy for convenient and large-scale synthesis of ultrafine MOCPs nanoparticles(size 50-100 nm) with obvious advantages such as fast synthesis,high yields,low costs and reduced synthetic steps.The bimetallic Ru/Co-MOCPs are further pyrolyzed to obtain bimetallic Coand low content of Ru-based nanoparticles embedded within nitrogen-doped carbon(Ru/Co@N-C) as an efficient catalyst used in Li-O_(2)battery.The Ru/Co@N-C provides porous carbon framework for the ion transportation and O_(2)diffusion,and has large amounts of metal/nonmetal sites as active site to promote the oxygen reduction reaction(ORR)/oxygen evolution reaction(OER) in Li-O_(2)batteries.As a consequence,a high discharge specific capacity of 15246 mA h g^(-1)at 250 mA g^(-1), excellent rate capability at different current densities,and stable overpotential during cycling,are achieved.This work opened up a new understanding for the industrialized synthesis of ultrafine catalysts for Li-O_(2)batteries with excellent structural characteristics and electrochemical performance.

High‑Quality Epitaxial N Doped Graphene on SiC with Tunable Interfacial Interactions via Electron/Ion Bridges for Stable Lithium‑Ion Storage

Tailoring the interfacial interaction in SiCbased anode materials is crucial to the accomplishment of higher energy capacities and longer cycle lives for lithium-ion storage.In this paper,atomic-scale tunable interfacial interaction is achieved by epitaxial growth of high-quality N doped graphene(NG)on SiC(NG@SiC).This well-designed NG@SiC heterojunction demonstrates an intrinsic electric field with intensive interfacial interaction,making it an ideal prototype to thoroughly understand the configurations of electron/ion bridges and the mechanisms of interatomic electron migration.Both density functional theory(DFT)analysis and electrochemical kinetic analysis reveal that these intriguing electron/ion bridges can control and tailor the interfacial interaction via the interfacial coupled chemical bonds,enhancing the interfacial charge transfer kinetics and preventing pulverization/aggregation.As a proof-of-concept study,this well-designed NG@SiC anode shows good reversible capacity(1197.5 mAh g^(−1)after 200 cycles at 0.1 A g^(−1))and cycling durability with 76.6%capacity retention at 447.8 mAh g^(−1)after 1000 cycles at 10.0 A g^(−1).As expected,the lithium-ion full cell(LiFePO_(4)/C//NG@SiC)shows superior rate capability and cycling stability.This interfacial interaction tailoring strategy via epitaxial growth method provides new opportunities for traditional SiC-based anodes to achieve high-performance lithium-ion storage and beyond.

金属有机框架-离子液体混合催化剂用于电化学还原二氧化碳生成甲烷

二氧化碳电化学还原(CO_(2)RR)制备碳氢化合物是一项极具应用前景的技术.该技术不仅可以有效减少二氧化碳在大气中的积累,还可以储存可再生能源.然而,由于现有的CO_(2)RR电催化剂的活性和法拉第效率较低,难以实现大规模应用.离子液体电解质可以有效提高CO_(2)RR的选择性,但成本太高,将离子液体固定在异相电催化剂的孔洞中可以大幅减少离子液体的用量.本文设计了一种混合HKUST-1金属-有机框架(MOF)-氟化咪唑基室温离子液体的电催化剂,将1-丁基-3-甲基咪唑六氟磷酸盐([BMIM][PF6])和1-乙基-3-甲基咪唑四氟硼酸盐([EMIM][BF_(4)])室温离子液体在真空氛围中被负载到水热合成的HKUST-1微粒孔隙中形成复合催化剂,该催化剂可以选择性地将CO_(2)还原为CH_(4).X射线光电子能谱(XPS)结果表明,室温离子液体和HKUST-1 MOF的Cu中心之间存在明显的电子相互作用,其中低氧化态的Cu比例较高.X射线衍射(XRD)和透射电子显微镜(TEM)结果表明,室温离子液体的负载没有显著改变MOF的晶体结构及其形态.与原始的HKUST-1电催化剂相比,HKUST-1/[BMIM][PF_(6)]混合催化剂的CH_(4)法拉第效率(FE)明显提高.在‒1.13 V vs.RHE时,最大CH_(4) FE和分电流密度分别为65.5%和11.5 mA cm^(-2).同时,混合催化剂的析氢反应(HER)活性显著降低,在‒1.09 V vs.RHE时H_(2) FE只有6.8%.稳定性测试结果表明,CH_(4) FE可以稳定保持在50%以上.由于在HKUST-1/[BMIM]和HKUST-1/[EMIM][BF_(4)]混合催化剂的测试中观察到了类似的促进CH_(4)和抑制HER的趋势,可以推断室温离子液体的疏水性在提高CO_(2)RR选择性方面只起到次要作用.电解后催化剂表面形成纳米级铜簇,可能是真正的活性位点.基于实验结果,本文还模拟了表面吸附了[BMIM][PF_(6)]分子的Cu(110)晶面,密度泛函理论(DFT)计算结果表明,在表面存在室温离子液体的情况下,Cu的分态密度(PDOS)峰正移,表明Cu可以与CO_(2)RR的反应中间体形成更强的键.HER的自由能图结果表明,室温离子液体的存在明显增强了H的吸附,从而通过增加*H的脱附能垒来阻碍析氢.此外,对CO_(2)到CH_(4)反应路径的计算表明,室温离子液体的存在降低了CO_(2)-CH_(4)的热力学能垒.

Mitochondria-targeted atovaquone promotes anti-lung cancer immunity by reshaping tumor microenvironment and enhancing energy metabolism of anti-tumor immune cells

Dear Editor,Atovaquone(ATO),a mitochondrial inhibitor,has anti-cancer effects[1].Based on ATO,we developed mitochondria-targeted atovaquone(Mito-ATO)that had even stronger anti-tumor efficacy than ATO[2].We syn-thesized Mito-ATO by attaching the bulky triphenylphos-phonium(TPP)group to ATO via a ten-carbon alkyl chain(Supplementary file of methods;Supplementary Figure S1).

Overview and countermeasures of cancer burden in China

Cancer is one of the leading causes of human death worldwide.Treatment of cancer exhausts significant medical resources,and the morbidity and mortality caused by cancer is a huge social burden.Cancer has therefore become a serious economic and social problem shared globally.As an increasingly prevalent disease in China,cancer is a huge challenge for the country’s healthcare system.Based on recent data published in the Journal of the National Cancer Center on cancer incidence and mortality in China in 2016,we analyzed the current trends in cancer incidence and changes in cancer mortality and survival rate in China.And also,we examined several key risk factors for cancer pathogenesis and discussed potential countermeasures for cancer prevention and treatment in China.

Circular RNA circCCNB1 inhibits the migration and invasion of nasopharyngeal carcinoma through binding and stabilizing TJP1 mRNA

Nasopharyngeal carcinoma(NPC)is a malignant tumor that usually occurs in people from Southeast Asia and Southern China.NPC is prone to migration and invasion,leading to poor prognosis.A large number of circular RNAs(circ RNAs)exacerbate the process of metastasis in NPC;however,their underlying mechanisms remain unclear.We found that the circular RNA circ CCNB1,encoded by the oncogene CCNB1,was downregulated in NPC biopsies and cell lines.In vitro assays show that circ CCNB1 inhibits NPC cell migration and invasion.Moreover,circ CCNB1 induces a protein,nuclear factor 90(NF90),to bind and prolong the half-life of tight junction protein 1(TJP1)m RNA.Upregulation of TJP1 enhances tight junctions between cancer cells and inhibits NPC cell migration and invasion.This study reveals a novel biological function of circ CCNB1 in the migration and invasion of NPC by enhancing the tight junctions of cancer cells by binding to NF90 proteins and TJP1 m RNA,and may provide a potential therapeutic target for NPC.

Organic frameworks confined Cu single atoms and nanoclusters for tandem electrocatalytic CO_(2) reduction to methane

The electrochemical reduction reaction of carbon dioxide(CO_(2)RR)is considered to be an effective way to realize carbon neutrality.As a type of intensively studied materials,covalent organic frameworks(COFs)with a tunable pore structure and various functional groups are promising catalysts for CO_(2)RR.Herein,COF synthesized by 2,6‐diaminoanthraquinone and 2,4,6‐triformylphloroglucinol is employed to assist the synthesis of electrocatalysts from Cu single atoms(SAs)to nanoclusters by controlling the electrodeposition.A tandem catalyst for CO_(2)‐to‐CH4 conversion is thus achieved by the Cu nanoclusters dispersed among the isolated Cu SAs in the COF network.It is proposed that CO_(2) is first reduced to CO over the atomically isolated Cu SAs,followed by diffusion onto the neighboring Cu nanoclusters for further reduction into CH4.In addition,mechanistic analysis suggests that the coordinated K^(+)ions on the COF network promote the activation of CO_(2) and the adsorption of reaction intermediates,thus realizing the suppressed hydrogen evolution reaction and selective production of CH4.This study presents a new insight of COFs for the confined synthesis of a tunable SA to nanocluster electrocatalysts,disclosing the great potential of COFs in electrocatalysis.

Platinum on nitrogen doped graphene and tungsten carbide supports for ammonia electro-oxidation reaction

Ammonia electrooxidation reaction involving multistep electron-proton transfer is a significant reaction for fuel cells,hydrogen production and understanding nitrogen cycle.Platinum has been established as the best electrocatalyst for ammonia oxidation in aqueous alkaline media.In this study,Pt/nitrogen-doped graphene(NDG)and Pt/tungsten monocarbide(WC)/NDG are synthesized by a wet chemistry method and their ammonia oxidation activities are compared to commercial Pt/C.Pt/NDG exhibits a specific activity of 0.472 mA·cm^(-2),which is 44%higher than commercial Pt/C,thus establishing NDG as a more effective support than carbon black.Moreover,it is demonstrated that WC as a support also impacts the activity with further 30%increase in comparison to NDG.Surface modification with Ir resulted in the best electro-catalytic activity with Pt-IrAVC/NDG having almost thrice the current density of commercial Pt/C.This work adds insights regarding the role of NDG and WC as efficient supports along with significant impact of Ir surface modification.