通过晶面调控产生强内建电场以提高卟啉光催化剂的H_(2)O_(2)生成速率

过氧化氢(H_(2)O_(2))是一种重要的化工产品,广泛应用于污水处理、消毒杀菌和印染漂白等领域.在蒽醌法生产H_(2)O_(2)的过程中,易产生有毒气体并存在爆炸危险.因此,仅利用水、氧气和太阳光即可在合适的光催化剂上生成H_(2)O_(2)的光催化技术备受关注.本课题组报道了通过酸碱自组装法制备的四(4-羧基苯基)卟啉(SA-TCPP)光催化剂,用于生产H_(2)O_(2).该催化剂克服了大部分H_(2)O_(2)光催化剂存在的需要牺牲剂、活性低和光利用率不足等问题,但其性能仍受限于较高的复合率.晶面调控已被证实是改善许多无机催化剂电荷复合的有效策略,然而,对于有机光催化剂,关于暴露晶面与其活性关系的研究仍然较少.本文采用溶解-重结晶法在水和三种有机溶剂的混合物中成功合成了三种具有不同暴露晶面的卟啉光催化剂.即利用卟啉在有机溶剂和水中的溶解度差异,将卟啉先溶解在四氢呋喃(THF)、甲醇(MeOH)或乙二醇(EG)溶液中,随后在水溶液中重新结晶.X射线衍射、高分辨率透射电子显微镜及晶面模拟模型图的结果表明,三种催化剂具有相同的晶体结构,但分别暴露了(400)、(022)和(020)晶面.通过紫外分光光度计测量这些催化剂在氙灯(λ≥420 nm)照射下的光催化活性,结果表明,具有(400)暴露面的卟啉光催化剂的H_(2)O_(2)生产速率最高,可达29.33 mmol L h^(-1)g^(-1),分别是具有(022)暴露面和(020)暴露面的卟啉光催化剂的2.7倍和4.1倍,约是已报道的SA-TCPP光催化剂的1.3倍.通过紫外漫反射、莫特肖特基曲线分析以及LED灯照射下的光催化活性测试,排除了光吸收能力对这三种卟啉光催化剂活性的影响.开尔文探针力显微镜、光生电流密度谱图、晶面模拟模型图和密度泛函理论计算结果表明,活性的差异主要归因于(400)表面暴露的高羧基含量所引发的强内建电场,并且在该暴露面上的内建电场方向有利于空穴从吡咯氮向羧基碳的跃迁,因此阻碍了电荷的快速重组,促进了富有挑战性的水氧化过程,而(020)面由于暴露了最多的吡咯氮和最少的羧基碳,其产生的内建电场强度最弱,且内建电场方向阻碍了空穴向羧基碳的跃迁,因此H_(2)O_(2)生产速率最低.综上所述,本工作通过晶面调控产生强内建电场以加速空穴的迁移,降低了电子空穴复合速率,实现了高H_(2)O_(2)生产速率,为更高效的有机光催化剂的设计和开发提供了新思路.

货币政策、会计信息质量与企业非效率投资

本文以2008-2016年度深交所非金融类上市公司为研究对象，以货币政策为切入点，研究会计信息质量对企业非效率投资的影响。研究发现提高会计信息质量能够有效治理企业非效率投资，但货币政策对会计信息质量和企业非效率投资二者之间关系的影响具有非对称性，紧缩的货币政策不仅会增强企业会计信息质量对投资不足的缓解作用，还会减弱会计信息质量对投资过度的抑制作用。

Research progress on methane conversion coupling photocatalysis and thermocatalysis

Conversion of methane into value-added chemicals is of significance for methane utilization and industrial demand of primary chemical products.The barrier associated with the nonpolar structure of methane and the high bond energy C-H bond(4.57 eV)makes it difficult to realize methane conversion and activation under mild conditions.The photothermal synergetic strategy by combining photon energy and thermo energy provides an advanced philosophy to achieve efficient methane conversion.In this review,we overview the current pioneering studies of photothermal methane indirect conversion and present the methane direct conversion by the way of photocatalysis and thermocatalysis to provide a fundamental understanding of methane activation.Finally,we end this review with a discussion on the remaining challenges and perspectives of methane direct conversion over single-atom catalysts via photothermal synergetic strategy.

Clinical application of individualized total arterial coronary artery bypass grafting in coronary artery surgery

BACKGROUND Total arterial revascularization is associated with increased patency and long-term efficacy and decreased perioperative morbidity and mortality and incidence of cardiac-related events and sternal wound infection compared with conventional coronary artery bypass surgery(CABG),in which the left internal mammary artery(LIMA)is typically grafted to the left anterior descending artery with additional saphenous vein grafts often used.This study determined whether these favorable clinical results could be realized at the authors’institute.AIM To summarize the early efficacy and clinical experience of individualized total arterial coronary artery bypass grafting surgery.METHODS CABG was performed on 35 patients with non-single-vessel coronary artery disease by adopting total arterial grafts at Fourth Affiliated Hospital of Harbin Medical University between April 2016 and December 2019.LIMA was used in 35 patients,radial artery(RA)was used in 35 patients,and right gastroepiploic artery(RGEA)was used in 9 patients.Perioperative complications were observed,short-term graft patency rate was followed-up,and quality of life was assessed.RESULTS All patients underwent off-pump coronary artery bypass and the surgeries were successful.All of them were discharged without any complications or deaths.During the follow-up,it was found that patients’angina symptoms were relieved and New York Heart Association classification for cardiac function was class I to class II.A total of 90 vessels were grafted with no occlusion for internal mammary artery,three occlusions for RA,and one occlusion for RGEA.CONCLUSION The individualized total arterial strategy based on the vessels targeting individual anatomic characteristics can achieve complete revascularization with satisfactory short-term grafting patency rate.

意识形态传播成效提升的媒体融合视域审视

主流意识形态传播是主流意识形态建设的关键一环,媒体融合作为媒介传播领域的新变革无疑为其提供了新的时空场域。在把握媒体融合带给意识形态传播机遇的基础上,要充分认识主流意识形态传播界域出现的控制力、影响力和解释力消解矛盾问题,同时审视传播主体、传播内容、传播方式三个重要部分,试图通过提升主体媒体素养、注重内容生产、创新传播平台更好地趋利规劣,提升主流意识形态传播成效。

Advances in electrocarboxylation reactions with CO_(2)

Recently,significant research has been conducted on the conversion of carbon dioxide(CO_(2))into value-added chemicals.With the decreasing cost of clean electricity,electrochemical methods have emerged as potential approaches for converting and fixing CO_(2).Organic electrochemical synthesis is a promising method for utilizing CO_(2)because it transforms CO_(2)into higher-value chemicals.This review introduces the research aspects of CO_(2)conversion and the mechanisms of CO_(2)organic electrocarboxylation reactions.Recent progress in electrocarboxylation with CO_(2)is discussed,considering organic substrates and cathode types under different reaction mechanisms.Finally,the challenges and prospects in this field are highlighted with the aim of further promoting the fundamental understanding of CO_(2)organic electrocarboxylation.

1T-phase MoS_(2)edge-anchored Pt_(1)-S_(3)active site boosting selective hydrogenation of biomass-derived maleic anhydride

Selective hydrogenation of biomass-derived maleic anhydride(MAH)to succinic anhydride(SA)is valuable but remains a challenge due to the complicated reaction network.We here report that single Pt atoms decorated onto the edges of two-dimensional(2D)1Tphase MoS_(2)(Pt1/1T-MOS_(2)SAC)as a proof-of-concept catalyst can efficiently convert biomass-derived MAH to SA with 100%conversion and 100%selectivity under mild conditions.The kinetic data and characterization results suggest that the catalytic performance of the edge-anchored Pt1/1T-MoS_(2)SAC originates from the facile H_(2)dissociation induced by the electron-deficient Pt1atoms and the pocket-like configuration of Pt1active site confines the adsorption configuration of MAH by the steric effect.The strategy of fabricating edge-confined catalysts offers a new direction to design novel SACs for biomass-derived transformations.

Enhancing Controllability Robustness of q-Snapback Networks through Redirecting Edges

Te well-known small-world network model was established by randomly rewiring edges,aiming to enhance the synchronizability of an undirected nearest-neighbor regular network.Tis paper demonstrates via extensive numerical simulations that randomly redirecting edges could enhance the robustness of the network controllability for directed snapback networks against both random and intentional node-removal and edge-removal attacks.

A 3D/0D cobalt-embedded nitrogen-doped porous carbon/supramolecular porphyrin magnetic-separation photocatalyst with highly efficient pollutant degradation and water oxidation performance

A 3D/0D cobalt-embedded nitrogen-doped porous carbon nanocubes(Co-N-C)/supramolecular tetra(4-carboxylphenyl)porphyrin nanocrystals(SA-TCPP)photocatalyst was successfully self-assembled viaπ–πinteraction,hydrogen bonding,and chemical bonding.Co-N-C/SA-TCPP heterostructure exhibited satisfactory visible photocatalytic oxidation performance on pollutant degradation and water evolution.The degradation rates of Co-N-C/ST(30%)composite towards 2,4-dichlorophenol,ofloxacin,and ethylene were10.9,7.2,and 2.1 times faster than SA-TCPP,respectively.The oxygen evolution efficiency was 1.9 times higher than SA-TCPP.The remarkably improved oxidation activities of Co-N-C/SA-TCPP were mainly ascribed to the following reasons:(1)Co-N-C could enhance the light absorption ability of SA-TCPP to produce more photoinduced carriers.(2)The well-developed porosity of Co-N-C could optimize the dispersibility of SA-TCPP to provide more reactive sites and charge separation channels.(3)Theπ–πinteraction between SA-TCPP and Co-N-C was beneficial to interlayer charge mobility,while the embedded cobalt nanoparticles(Co NPs)and N-doped carbon matrix could serve as electron traps to accelerate interfacial electron transfer.Additionally,the ferromagnetic Co NPs endowed Co-N-C/SA-TCPP with magnetic-separation function to promote recyclability in practical application.