Coupling of BiOCl Ultrathin Nanosheets with Carbon Quantum Dots for Enhanced Photocatalytic Performance

Over the past few decades,photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding photocatalytic activities has become a research hotspot in this field.In this study,we prepared a series of photocatalysts in which BiOCl nanosheets were modified with carbon quantum dots(CQDs)to form CQDs/BiOCl composites by using a simple solvothermal method.The photocatalytic performance of the resulting CQDs/BiOCl composite photocatalysts was assessed by rhodamine B and tetracycline degradation under visible-light irradiation.Compared with bare BiOCl,the photocatalytic activity of the CQDs/BiOCl composites was significantly enhanced,and the 5 wt%CQDs/BiOCl composite exhibited the highest photocatalytic activity with a degradation efficiency of 94.5%after 30 min of irradiation.Moreover,photocatalytic N_(2)reduction performance was significantly improved after introducing CQDs.The 5 wt%CQDs/BiOCl composite displayed the highest photocatalytic N_(2)reduction performance to yield NH_3(346.25μmol/(g h)),which is significantly higher than those of 3 wt%CQDs/BiOCl(256.04μmol/(g h)),7 wt%CQDs/BiOCl(254.07μmol/(g h)),and bare BiOCl(240.19μmol/(g h)).Our systematic characterizations revealed that the key role of CQDs in improving photocatalytic performance is due to their increased light harvesting capacity,remarkable electron transfer ability,and higher photocatalytic activity sites.

Sedimentary characteristics and genetic mechanism of the giant ancient pockmarks in the Qiongdongnan Basin,northern South China Sea

In the late Miocene,giant ancient pockmarks,which are fairly rare globally,developed in the Qiongdongnan Basin.In this paper,to determine the sedimentary characteristics and genetic mechanism of these giant ancient pockmarks in the Yinggehai Formation of the Qiongdongnan Basin,based on high-resolution 3D seismic data and multiattribute fusion technologies,we analyzed the planar distribution and seismic facies of the ancient pockmarks and compared the characteristics of the ancient pockmarks with those of channels,craters,and hydrate pits.Moreover,we also discussed the implications of the fluid escape system and paleo-bottom current activity in the ancient pockmark development area and analyzed the influence of the ancient pockmarks on the paleoclimate in this region.Finally,an evolutionary model was proposed for the giant ancient pockmarks.This model shows that the giant ancient pockmarks in the southern Qiongdongnan Basin were affected by both deep fluid escape and lateral transformation of paleobottom currents.In addition,the giant ancient pockmarks contributed to the atmospheric CO_(2)concentration in the late Miocene and played a great role in the contemporary evaluation of deepwater petroleum exploration.

Highly active sites of NiVB nanoparticles dispersed onto graphene nanosheets towards efficient and pH-universal overall water splitting

Production of hydrogen(H2) and oxygen(O2) through electrocatalytic water splitting is one of the sustainable,green and pivotal ways to accomplish the ever-increasing demands for renewable energy sources,but remains a big challenge because of the uphill reaction during overall water splitting.Herein,we develop high-performance non-noble metal electrocatalysts for pH-universal water splitting,based on nickel/vanadium boride(NiVB) nanoparticles/reduced graphene oxide(rGO) hybrid(NiVB/rGO)through a facile chemical reduction approach under ambient condition.By virtue of more exposure to surface active sites,superior electron transfer capability and strong electronic coupling,the asprepared NiVB/rGO heterostructure needs pretty low overpotentials of 267 and 151 mV to deliver a current density of 10 mA cm^(-2) for oxygen evolution reaction(OER) and hydrogen evolution reaction(HER)respectively,with the corresponding Tafel slope of 44 and 88 mV dec^(-1) in 1.0 M KOH.Moreover,the NiVB/rGO electrocatalysts display a promising performance in a wide-pH conditions that require low overpotential of 310,353 and 489 mV to drive a current density of 10 mA cm^(-2) for OER under 0.5 M KOH,0.05 M H2SO4 and 1.0 M phosphate buffer solution(PBS) respectively,confirming the excellent electrocata lytic performance among state-of-the-art Ni-based electrocatalysts for overall water splitting.Therefore,the interfacial tuning based on incorporation of active heterostructure may pave a new route to develop bifunctional,cost-effective and efficient electrocatalyst systems for water splitting and H2 production.

利用室温磷光碳点提供的超长寿命三重态激子促进石墨相氮化碳的光催化性能

半导体光催化剂目前受到了广泛的关注与研究,但其光生电子和空穴的复合导致能量损失,制约着这类催化剂的应用.本工作利用具有超长寿命的三重态激子来促进电子和空穴对的有效分离,以产生更多的自由载流子.与传统的荧光碳点(CD)相比,高度分散在石墨相氮化碳上的室温磷光(RTP)碳点显示出显著提升的光催化能力和电化学活性.实验和理论计算都表明,RTP CD@g-C_(3)N_(4)可以作为“能量缓释胶囊”,不断提供长寿命的三重态激子,从而有效地调控电子和空穴对的解离,并增强催化剂固有的光催化性能(包括水分解和染料降解反应).本工作提供了一种将超长寿命三重态激子用作光催化剂的设计思路.

Extracorporeal membrane oxygenation in fatal methemoglobinemia caused by sodium nitrite:A case report and review of the literature

Introduction Nitrites,as a powerful kind of oxidizing agent,can oxidize ferrous ions(Fe^(2+))to ferric ions(Fe^(3+)),triggering the conversion of normal hemoglobin(Hb)to methemoglobin(MetHb),which loses its ability to carry oxygen,resulting in hypoxia in tissues and death in severe cases.

典型煤层水微生物产甲烷潜力及其群落结构研究

内蒙古自治区二连盆地、海拉尔盆地是我国重要的煤层气产区,其中生物成因煤层气是煤层气的重要来源,但复杂物质转化产甲烷相关微生物群落结构及功能尚不清楚。【目的】研究煤层水中的微生物代谢挥发性脂肪酸产甲烷的生理特征及群落特征。【方法】以内蒙古自治区二连盆地和海拉尔盆地的四口煤层气井水作为接种物,分别添加乙酸钠、丙酸钠和丁酸钠厌氧培养;定期监测挥发性脂肪酸降解过程中甲烷和底物的变化趋势,应用高通量测序技术,分析原始煤层气井水及稳定期产甲烷菌液的微生物群落结构。【结果】除海拉尔盆地H303煤层气井微生物不能代谢丙酸外,其他样品均具备代谢乙酸、丙酸和丁酸产生甲烷的能力,其生理生态参数存在显著差异,产甲烷延滞期依次是乙酸<丁酸<丙酸;最大比产甲烷速率和底物转化效率依次是丙酸<乙酸<丁酸。富集培养后,古菌群落结构与煤层气井水的来源显著相关,二连盆地优势古菌为氢营养型产甲烷古菌Methanocalculus(相对丰度13.5%–63.4%)和复合营养型产甲烷古菌Methanosarcina(7.9%–51.3%),海拉尔盆地的优势古菌为氢营养型产甲烷古菌Methanobacterium(24.3%–57.4%)和复合营养型产甲烷古菌Methanosarcina(29.6%–66.5%);细菌群落则与底物类型显著相关,硫酸盐还原菌Desulfovibrio(12.0%–41.0%)、互营丙酸氧化菌Syntrophobacter(39.6%–75.5%)和互营丁酸菌Syntrophomonas(8.5%–21.9%)分别在乙酸钠、丙酸钠和丁酸钠处理组显著富集。【结论】煤层气井水微生物可降解挥发性脂肪酸(乙酸、丙酸和丁酸)并具有产甲烷潜力;乙酸可能被古菌直接代谢产甲烷,而丙酸和丁酸通过互营细菌和产甲烷古菌代谢产甲烷。Desulfovibrio、Syntrophobacter和Syntrophomonas分别在乙酸、丙酸和丁酸代谢过程中发挥了重要作用。这些结果为煤层气生物强化开采提供了一定的微生物资源基础。

White-light emission and tunable room temperature phosphorescence of dibenzothiophene

Molecular materials exhibiting room temperature phosphorescence(RTP) have received much attention during last few years. It has been known that different stacking fashions(e.g., formation of polymorph) and aggregation/crystal states could largely influence the RTP efficiency. However, whether the crystal morphology or shape could play a key role in modulation of the RTP has not been detected yet. In this work, we report that the dibenzothiophene(DBT) with the same molecular stacking fashion but different crystal morphologies can present alternated RTP performances. By modulation of the fluorescence and phosphorescence dual emission, a direct warm-white color light-emitting has also been successfully achieved. Moreover, the RTP emission can be further tuned through hybridization with β-cyclodextrin in different ratios, with the longest lifetime of 0.43 s.

Room-Temperature Phosphorescent Organic-Doped Inorganic Frameworks Showing Wide-Range and Multicolor LongPersistent Luminescence

Long-persistent luminescence based on purely inorganic and/or organic compounds has recently attracted much attention in a wide variety of fields including illumination,biological imaging,and information safety.However,simultaneously tuning the static and dynamic afterglow performance still presents a challenge.In this work,we put forward a new route of organic-doped inorganic framework to achieve wide-range and multicolor ultralong room-temperature phosphorescence(RTP).Through a facile hydrothermal method,phosphor(tetrafluoroterephthalic acid(TFTPA))into the CdCO_(3)(or Zn_(_(2))(OH)_(2)CO_(3))host matrix exhibits an excitation-dependent colorful RTP due to the formation of diverse molecular aggregations with multicentral luminescence.The RTP lifetime of the doped organic/inorganic hybrids is greatly enhanced(313 times)compared to the pristine TFTPA.The high RTP quantum yield(43.9%)and good stability guarantee their easy visualization in both ambient and extreme conditions(such as acidic/basic solutions and an oxygen environment).Further codoped inorganic ions(Mn_(2)+and Pb_(2)+)afford the hybrid materials with a novel time-resolved tunable afterglow emission,and the excitation-dependent RTP color is highly adjustable from dark blue to red,covering nearly the whole visible spectrum and outperforming the current stateof-the-art RTP materials.Therefore,this work not only describes a combined codoping and multicentral strategy to obtain statically and dynamically tunable long-persistent luminescence but also provides great opportunity for the use of organicinorganic hybrid materials in multilevel anticounterfeiting and multicolor display applications.

硅基-钙钛矿叠层太阳能电池的光管理策略

硅基-钙钛矿叠层太阳能电池的研究进展迅速,两端叠层器件的最高效率在短短几年内就达到了29.8%,有效解决了硅太阳能电池效率受限于肖克利-奎伊瑟(Shockley-Queisser)极限而难以大幅度提升的问题.两端硅基-钙钛矿叠层器件的主要结构是由宽带隙的钙钛矿顶电池和窄带隙的硅基底电池组成,其中顶电池吸收高能光子,底电池吸收低能光子,达到扩大光吸收范围的作用.然而,由于硅基-钙钛矿叠层器件功能层多且器件结构较为复杂,光吸收过程中会产生多种吸光损失,光吸收的分配不合理也会导致无法充分利用入射的光子以达到最佳的器件效率.可靠的光管理策略是改善上述问题的有效方法,一方面通过钙钛矿的带隙调控等方式,对顶电池和底电池进行合理的光吸收分配,可以有效促进子电池间的电流匹配.另一方面,通过选择合适的功能层、构建陷光结构等方法有效减少寄生吸收、反射以及透射损失,提高入射光利用率,最终提高整体叠层器件的效率.本文首先介绍了光吸收损失的主要形式,然后从钙钛矿顶电池和硅基底电池两方面的光管理策略入手,总结分析目前领域内关于提高光吸收范围、优化光吸收分配、抑制光吸收损失等方面的研究工作进展,最后对目前仍然存在的问题和未来的发展作了总结与展望.

Selective formation of luminescent chiral cocrystal:Molecular self-assembly of 2,20-binaphthol and 2-(3-pyridyl)-1H-benzimidazole

Luminescent cocrystals have been received much attention in fluorescence imaging and sensor application. In this work, we report that the high-quality chiral luminescent cocrystal can be obtained through a molecular self-assembly process of 2,20-binaphthol and 2-（3-pyridyl）-1 H-benzimidazole. The assembly modes and stacking fashions of as-obtained cocrystal were determined by single crystal X-ray diffractometer. The structure and optical properties of the cocrystals were characterized by fluorescence emission, fluorescence decay, Raman and circular dichroism spectra. The results show that both the pristine co-assembled units（R-BINOL and S-BINOL） give rise to the R conformation within the final cocrystal, suggesting that the formation of cocrystal can be an effective way to achieve R/S-isomeric transformation of 2,20-binaphthol. It is also expected that the co-crystallization approach has much flexibility and potential applications for the design and selective formation of chiral luminescent materials.

In situ localization of BiVO_(4) onto two-dimensional MXene promoting photoelectrochemical nitrogen reduction to ammonia

The existing industrial ammonia synthesis usually adopts the Haber-Bosch process,which requires harsh conditions of high temperature and high pressure,and consumes high energy.Under this circumstance,photoelectrochemical(PEC)catalysis is regarded as a promising method for N_(2) reduction reaction(NRR),but bears problems of low efficiency and yield.Thus,exploring active catalysts remains highly desirable.In this work,BiVO_(4)@MXene hybrids have been facilely synthesized by a hydrothermal route.The heterojunctions by the in situ growth of BiVO_(4) onto two-dimensional(2D)MXene greatly increase the NRR efficiency:under photoelectric conditions,the optimized NH_(3) yield is 27.25µg h^(-1) cm^(-2),and the Faraday efficiency achieves 17.54% at−0.8 V relative to the reversible hydrogen electrode(RHE),which are higher than most state-of-the-art NRR(photo)electrocatalysts.The mechanism speculation shows the enhanced light absorption range and the heterojunction formation largely promote the separation and the transfer efficiency of photogenerated carriers,thereby improving the PEC catalytic ability.Therefore,this work provides a hybrid route to combine the advantages of photo and electric catalysis for effective artificial nitrogen fixation.

Design, Synthesis and SAR Studies of Novel and Potent Dipeptidyl Peptidase 4 Inhibitors

Dipeptidyl peptidase 4(DPP-4)is a clinically validated target for the treatment of type 2 diabetes mellitus(T2DM).To discover novel and potent DPP-4 inhibitors,three series of compounds were designed and synthesized in this study based on our previously identified novel scaffold of 2-phenyl-3,4-dihydro-2H-benzo[f]chromen-3-amine.Among the designed compounds,41d-1 was the most po tent one with an IC_(50) value of 16.00 nM.

Optimal Antithrombotic Therapy after Implantation of a Transcatheter Aortic Valve: Warfarin, Aspirin, or Non-Vitamin K Antagonist Oral Anticoagulants? A Systematic Review and Meta-Analysis

Objective:Diverse antithrombotic strategies were applied to patients undergoing aortic valve replacement.However,the optimal therapeutic regimen for patients undergoing transcatheter aortic valve implantation/replacement(TAVI/TAVR)remains unclear.The purpose of this study was to compare the efficacy and safety of various antithrombotic therapies following TAVI/TAVR.Methods:Relevant clinical trials evaluating the effect of anticoagulation or antiplatelet regimens on patients after TAVI/TAVR from inception to September 2020 were identified using the PubMed,EMBASE,and the Cochrane Library databases.The inclusion criteria including(1)all patients underwent TAVI/TAVR;(2)the interventions were antithrombotic strategies that prevent the occurrence of thrombotic events in patients;(3)randomized controlled trials or prospective observational studies;and(4)investigation of at least 1 outcome with a follow-up period of≥3 months.The exclusion criteria including(1)research content was identical or irrelevant to the purpose of the present study;(2)lack of the required outcome index or availability of fragmentary original information;and(3)the full text is not available.The major outcomes were all-cause mortality,thromboembolic complications,and bleeding events.The Cochrane Collaboration’s tool and the Newcastle-Ottawa Scale were used for assessing the risk of bias in included studies.Results:Thirteen studies(3 randomized controlled trials and 10 non-randomized studies)were identified,with a total of 23,497 patients.Four studies compared direct oral anticoagulants(DOACs)with warfarin,1 study compared aspirin with warfarin,6 studies compared aspirin plus clopidogrel(dual antiplatelet therapy(DAPT))with aspirin monotherapy,and 2 studies compared DAPT and aspirin monotherapy with warfarin concurrently.There were no significant differences found between the DOAC and warfarin groups regarding all-cause mortality(risk ratio(RR):1.03;95%confidence interval(CI):0.65–1.64;P=0.909;Phet=0.105),clinical adverse events(RR:1.59;95%CI:0.99–2.58;P=0.057;Phet=0.738),or bleeding events(RR:0.93;95%CI:0.78–1.11;P=0.437;Phet=0.338).The rates of all-cause mortality(RR:0.71;95%CI:0.54–0.93;P=0.012;Phet=0.845)and bleeding events(RR:0.43;95%CI:0.22–0.83;P=0.012;P_(het)=0.569)were lower in the aspirin group versus the warfarin group;however,there was no difference in the rate of clinical adverse events(RR:0.38;95%CI:0.14–1.07;P=0.068;Phet=0.593).The DAPT group had an advantage versus the aspirin group in all-cause mortality(RR:0.89;95%CI:0.82–0.98;P=0.013;Phet=0.299);however,the incidence of bleeding events(RR:2.06;95%CI:1.39–3.07;P<0.001;Phet=0.001)exhibited an increasing trend.Notably,there was a slight decrease in the incidence of clinical adverse events(RR:1.09;95%CI:0.94–1.26;P=0.268;Phet=0.554).Conclusion:The present meta-analysis integrates the latest published results on antithrombotic strategies in patients after TAVI/TAVR.Aspirin showed a favorable risk-benefit profile versus warfarin,with lower rates of all-cause mortality and bleeding events.Although DAPT was also associated with a significantly lower rate of all-cause mortality,it was linked to a higher incidence of bleeding events.The DOACs did not show significant benefits compared with warfarin.Some certain limitations should be noted,such as different types of trails produce heterogeneity and finite inclusion of TAVI/TAVR patients increased selection bias.