铟基三元金属硫化物催化剂在光催化二氧化碳还原领域中的研究进展

化石能源的过度使用造成CO_(2)大量排放,导致了环境问题,同时引发了能源危机.新能源技术的快速发展为缓解上述问题提供了有效途径.光催化CO_(2)转化技术因绿色环保、成本低廉、反应条件温和、操作安全可控而引起了研究者们的广泛关注.推动光催化CO_(2)转化技术发展的关键在于高效光催化剂的精准设计与合成.目前,已经发展了多种光催化剂.铟基三元金属硫化物因具有合适的能带结构、较宽的吸光范围和独特的双金属位点而成为光催化CO_(2)还原领域的研究热点之一.独特的双金属结构使其具有更丰富的活性位点,同时可以调控对关键中间体的吸附和解吸,进而提高CO_(2)反应活性,并精准调控目标产物的选择性.然而,缓慢的电子传输行为和高载流子复合效率阻碍了CO_(2)还原反应效率的提升,因此,目前距离实现光催化CO_(2)还原技术的工业化应用仍有较大的差距.为了克服上述难题,科学家们对铟基三元金属硫化物进行了大量研究,以期通过修饰改性进一步提高催化效率和选择性.然而,目前有关铟基三元金属硫化物在光催化CO_(2)还原领域应用研究进展的归纳和总结尚不充分,基于此类材料独特的性质,对其进行全面的总结分析是十分必要的.本文首先对光催化CO_(2)还原反应的基本原理进行了分析,探讨了影响其活性和选择性提升的关键要素.然后,对几种典型的铟基三元金属硫化物的结构、组成特性以及合成方法进行了详细归纳.重点围绕铟基三元金属硫化物的性能提升策略,如形貌与结构调控、缺陷工程以及复合材料的构建等,总结了其在光催化CO_(2)还原领域的最新研究进展,深入剖析了催化剂的设计策略与催化活性增强之间的构效关系,以及密度泛函理论计算和原位表征技术在该领域的应用.最后,总结了目前铟基三元金属硫化物研究所面临的挑战,并对未来发展方向进行了展望.

富含晶格畸变的多维In_(2)O_(3)/In_(2)S_(3)异质结调控用于光催化CO_(2)转化

利用光催化技术将CO_(2)进行有效转化是减少排放和实现可再生能源生产的理想途径之一.然而,较低的催化转化效率限制了其实际应用.因此,高效光催化剂的设计合成与改性是促进光催化CO_(2)还原技术发展的关键.在众多催化剂改性策略中,构建异质结构光催化体系是一种有效策略,不仅有利于提高载流子分离效率,还可以优化能级结构,同时改善光吸收.对于异质结材料,有效的界面接触对电子的动态行为起着重要作用,不仅可以为电子提供高速通道,还可以有效抑制光催化CO_(2)还原反应中光生载流子的复合.特别是载流子分离效率高和自由电子浓度增加,可有效促进CO_(2)分子的吸附和活化.此外,构建异质结也是缓解硫化物稳定性差的有效方法.值得注意的是,两种半导体在匹配过程中通常会形成大量的不饱和配位键和空位缺陷,在某种材料中甚至会发生晶格失配导致晶格畸变结构的形成.晶格畸变结构可以为催化反应提供额外的活性位点,并为反应进行提供温床.除光催化剂组成设计外,形貌的合理设计也对催化剂性能有较大影响,因为其不仅与光吸收能力和能带结构有关,而且在很大程度上影响着载流子的输运.近年来,中空结构材料因其独特的结构优势引起了光催化领域研究人员的广泛兴趣.内部空腔为光的多次反射和折射提供机会,进而提升光吸收和利用率.与本体结构相比,中空结构材料具有丰富的活性位点和较大的比表面积,能够为电子提供高速通道,因此,在表面催化反应中具有广阔的应用前景.特别是衍生的金属有机框架材料(MOFs)保留了原始材料的形貌结构,可以通过预先设计前驱体精确控制活性位点.因此,设计以MOFs为前驱体的中空结构催化剂有望提高光催化CO_(2)还原活性.本文通过简单的MOFs衍生策略和原位硫化法构筑了多维中空结构的In_(2)O_(3)/In_(2)S_(3)异质结.通过光反射和折射提高了其对光子的利用率;高度匹配的能级结构实现了电子-空穴对的有效分离;紧密的界面接触为进一步快速的光生电子转移到活性位提供了高速通道.此外,大量晶格畸变的形成和氧原子逃逸造成的氧空位,也为光生载流子的分离提供了驱动力;增加的自由电子浓度促进CO_(2)在催化剂表面的吸附和活化,使关键中间体*COOH处于较低的能垒.In_(2)O_(3)/In_(2)S_(3)异质结表现出较好的CO生成速率(12.2μmol g^(−1)h^(−1)),分别为In2O3和In_(2)S_(3)的4倍左右.本文为异质结光催化剂的构建提供有效策略.

甘草养阴汤对hTNF-α转基因关节炎模型小鼠肝脏代谢的影响

目的:甘草养阴汤(Gancao Nourish Yin,GCNY)已应用于临床类风湿性关节炎患者,其不仅可以控制疾病的发生发展,还可以改善患者的身体状况,但作用机制尚未得到研究。代谢紊乱与类风湿性关节炎相关,靶向代谢特征是控制该疾病的方法之一。本研究的目的是观察GCNY对人肿瘤坏死因子-α(human tumor necrosis factor alpha,hTNF-α)转基因关节炎模型小鼠代谢变化的影响。方法:将hTNF-α转基因关节炎模型小鼠分为对照组和甘草养阴汤组,每组6只。治疗8周后,取两组小鼠的肝组织进行液相色谱-质谱分析(liquid chromatography-mass spectrometry,LC/MS)。首先确定甘草养阴汤处理后发生显著变化的代谢物,之后对这些代谢物进行京都基因和基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)通路富集分析和网络分析。结果:肝脏中共检测到126种代谢物,与对照组比较,甘草养阴汤组17种代谢物发生显著变化。具体来说,甘草养阴汤处理后,硫胺素、γ-L-谷氨酰-L-缬氨酸、泛酸、吡哆醛(维生素B6)、琥珀酸、尿苷5′-二磷酸-葡萄糖醛酸、尿苷、尿囊酸、N-乙酰基-D-葡萄糖,葡萄糖胺、烟酰胺核糖苷和N2,N2-二甲基鸟苷显著下调,而异丁酰甘氨酸、N-乙酰尸胺、N-氨基甲酰-L-天冬氨酸、L-鹅肌氨酸、肌酸酐和顺式4-羟基-D-脯氨酸显著上调。六种代谢途径发生显著改变,包括丙氨酸、天冬氨酸和谷氨酸代谢、嘧啶代谢、硫胺素代谢、氨基糖和核苷酸糖代谢、泛酸和CoA生物合成以及柠檬酸循环(TCA循环)。综合代谢网络分析表明,甘草养阴汤可能分别通过抑制血管生成和促进白细胞渗入滑膜对类风湿性关节炎发挥双向调节作用。结论:甘草养阴汤可调节hTNF-α转基因关节炎模型小鼠的肝脏代谢。该汤剂的进一步优化可能会对类风湿性关节炎患者产生更好的疗效。

Interface-engineered MoS_(2)/CoS/NF bifunctional catalysts for highly-efficient water electrolysis

The utilization of non-noble metal catalysts with robust and highly efficient electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)are extremely important for the large-scale implementation of renewable energy devices.Integration of bifunctional electrocatalysts on both anode and cathode electrodes remains a significant challenge.Herein,we report on a novel and facile strategy to construct the ordered and aligned MoS_(2)nanosheet-encapsulated metal–organic frameworks(MOFs)derived hollow CoS polyhedron,in-situ grown on a nickel foam(NF).The starfish-like MoS_(2)/CoS/NF heterojunctions were formed due to the ordered growth of the material caused by NF substrate.The optimized 2-MoS_(2)/CoS/NF heterojunction exhibits robust bifunctional electrocatalytic activity with a low overpotential of 67 and 207 m V toward the HER and OER at 10 mA cm^(-2),and the long-term stability,which exceeds most of the reported bifunctional electrocatalysts.Such high electrocatalytic performance arises due to the synergistic effect between the MoS_(2)and CoS phases across the interface,the abundant active sites,as well as the hierarchical pore framework,which collectively enhance the mass and electron transfer during the reactions.The work provides a promising approach to fabricating bifunctional catalysts with custom-designed heterojunctions and remarkable performance for applications in electrochemical energy devices and related areas.

Cryo-induced closely bonded heterostructure for effective CO2 conversion:The case of ultrathin BP nanosheets/g-C3N4

Black phosphorus(BP),an interesting and multi-functional non-metal material,has attracted widespread attention.In this work,2D BP/2D g-C3N4 heterostructure had been fabricated at extremely low temperature,which was used to reduce CO2 for the first time.With introduction of 2D BP,the separation of photogenerated holes and electrons was extremely boosted,and composites showed excellent photocatalytic performance(CO2 to CO).Meanwhile,the targeted composite could keep high selectivity for CO generation and CO generation rate can be up to 187.7μmol g−1 h^−1.The formation process of the unique heterostructure and the key factor affecting the photocatalytic performance were also discussed.This work provides a new approach for designing metal free photocatalyst,which is used for CO2 reduction.

Synthesis of carbon nitride in moist environments:A defect engineering strategy toward superior photocatalytic hydrogen evolution reaction

Intimate understanding of the synthesis-structure-activity relationships is an accessible pathway to overcome the intrinsic challenges of carbon nitride(g-C_(3)N_(4))photocatalysts.This work looks in the effects of humidity of the synthesis process to the morphology,chemical structure,band structure as well as the photocatalytic activity of g-C_(3)N_(4) materials.Four g-C_(3)N_(4) samples were prepared by heating melem in four gas environments:dry Ar,dry Air,moist Ar and moist Air.The photocatalytic activity measurements revealed that the samples synthesized in moist inert and oxidic gases environments displayed 20 and 10 times the photocata lytic H_(2) evolution activity of the samples synthesized in dry inert and oxidic gases environments,respectively.The reasons for this remarkable variety in photocata lytic activities had been through investigated.After all,the terminations of the carbon vacancies were identified as the dominant factor in enhancing H_(2) evolution performance.The work here thus demonstrating an example of defect engineering.

Synchronous activation of Ag nanoparticles and BiOBr for boosting solar-driven CO_(2)reduction

Artificial photosynthesis of valuable chemicals from CO_(2)is a potential way to achieve sustainable carbon cycle.The CO_(2)conversion activity is still inhibited by the sluggish charge kinetics and poor CO_(2)activation.Herein,Ag nanoparticles coupled Bi OBr have been constructed by in-situ photoreduction strategy.The crafting of interface between Ag nanoparticles and Bi OBr nanosheets,achieving an ultra-fast charge transfer.The Bi OBr semiconductor excited electrons and plasmonic Ag nanoparticles generated high-energy hot electrons synchronous accelerates the C=O double bond activation.Thus,the optimized Ag/BiOBr-2 heterostructure shows excellent CO_(2)photoreduction activity with CO production of 133.75 and 6.83μmol/g under 5 h of 300 W Xe lamp and visible light(λ>400 nm)irradiation,which is 1.51 and 2.81 folds versus the pristine Bi OBr,respectively.The mechanism of CO_(2)photoreduction was in-depth understood through in-situ FT-IR spectrum and density functional theory calculations.This study provides some new perspectives into efficient photocatalytic CO_(2)reduction.

Unraveling the role of phase engineering in tuning photocatalytic hydrogen evolution activity and stability

In this work,taking NiSe_(2)as a prototype to be used as cocatalyst in photocatalytic hydrogen evolution,we demonstrate that the crystal phase of NiSe_(2)plays a vital role in determining the catalytic stability,rather than activity.Theoretical and experimental results indicate that the phase structure shows negligible influence to the charge transport and hydrogen adsorption capacity.When integrating with carbon nitride(CN)photocatalyst forming hybrids(m-NiSe_(2)/CN and p-NiSe_(2)/CN),the hybrids show comparable photocatalytic hydrogen evolution rates(3.26μmol/h and 3.75μmol/h).Unlike the comparable catalytic activity,we found that phase-engineered NiSe_(2)exhibits distinct stability,i.e.,m-NiSe_(2)can evolve H_(2) steadily,but p-NiSe_(2)shows a significant decrease in catalytic process(∼57.1%decrease in 25 h).The factor leading to different catalytic stability can be ascribed to the different surface conversion behavior during photocatalytic process,i.e.,chemical structure of m-NiSe_(2)can be well preserved in catalytic process,but partial p-NiSe_(2)tends to be converted to NiOOH.

A candy-like photocatalyst by wrapping Co, N-co-doped hollow carbon sphere with ultrathin mesoporous carbon nitride for boosted photocatalytic hydrogen evolution

Hierarchical carbon material is used as a star cocatalyst in the field of photocatalysis due to its excellent catalytic properties. In this work, mesoporous carbon nitride sheet(MCNS) photocatalyst introduced nitrogen-doped hollow carbon spheres assembled with cobalt nanoparticles(Co@NHC) is synthesized by electrostatic adsorption. A series of characterizations are analyzed to display the structures, morphologies and optical properties of as-prepared materials. The photocatalytic activity of Co@NHC/MCNS material is evaluated with hydrogen evolution under visible light irradiation. The results indicate that 5 wt%Co@NHC/MCNS material reveals higher photocatalytic activity of hydrogen evolution rate of 3675 μmol/g with 4 h reaction time, which is 159 times than that of pure MCNS material. The carbon material with excellent charge transport properties can effectively accelerate the charge transfer from ultrathin MCNS to cobalt nanoparticles. The goal of improving the photocatalytic performance of Co@NHC/MCNS material is achieved. As a result, it provides a feasible and promised approach for doping transition metals to enhance photocatalytic activity.

Photocatalytic degradation of methyl orange using ZnO/TiO_(2) composites

ZnO/TiO_(2)composites were synthesized by using the solvothermal method and ultrasonic precipitation followed by heat treatment in order to investigate their photocatalytic degradation of methyl orange(MO)in aqueous suspension under UV irradiation.The composition and surface structure of the catalyst were characterized by X-ray diffraction(XRD),field emission scanning electron microscope(FE-SEM),and transmission electron microscopy(TEM).The degradation efficiencies of MO at various pH values were obtained.The highest degradation efficiencies were obtained before 30 min and after 60 min at pH 11.0 and pH 2.0,respectively.A sample analysis was conducted using liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry.Six intermediates were found during the photocatalytic degradation process of quinonoid MO.The degradation pathway of quinonoid MO was also proposed.

2020 Roadmap on two-dimensional nanomaterials for environmental catalysis

Environmental catalysis has drawn a great deal ofattention due to its clean ways to produce useful chemicals or carry out some chemical processes.Photocatalysis and electrocatalysis play important roles in these fields.They can decompose and remove organic pollutants from the aqueous environment,and prepare some fine chemicals.Moreover,they also can carry out some important reactions,such as 02 reduction reaction(ORR),O2 evolution reaction(OER),H2 evolution reaction(HER),CO2 reduction reaction(C02 RR),and N2 fixation(NRR).For catalytic reactions,it is the key to develop high-performance catalysts to meet the demand fortargeted reactions.In recentyears,two-dimensional(2 D) materials have attracted great interest in environmental catalysis due to their unique layered structures,which offer us to make use of their electronic and structural characteristics.Great progress has been made so far,including graphene,black phosphorus,oxides,layered double hydroxides(LDHs),chalcogenides,bismuth-based layered compounds,MXenes,metal organic frameworks(MOFs),covalent organic frameworks(COFs),and others.This content drives us to invite many famous groups in these fields to write the roadmap on two-dimensional nanomaterials for environmental catalysis.We hope that this roadmap can give the useful guidance to researchers in future researches,and provide the research directions.

Crafting of plasmonic Au nanoparticles coupled ultrathin BiOBr nanosheets heterostructure: steering charge transfer for efficient CO_(2) photoreduction

Integrating semiconductor photocatalysts with outstanding visible light absorption and fast surface/interface charge transfer kinetics is still an enormous challenge for efficient CO_(2)photoreduction.In this work,the Au nanoparticles have been coupled with ultrathin BiOBr nanosheets,the formed heterostructure(Au/BiOBr)pos-sesses a localized surface plasmon resonance(LSPR)and enhances the visible light absorption ability,as well as forms a fast charge transport channel on the interface between Au and BiOBr.Thus,the heterostructure photo-catalyst exhibits higher photocatalytic CO_(2)to CO performance(135.3/16.43μmol g^(-1))than that of BiOBr(89.0/6.46μmol g^(-1))under 300 W Xe lamp and visible light(λ>400 nm)irradiation for 5 h,respectively.Finally,the in situ FT-IR spectroscopy revealed CO_(2)photoreduction process and found that the*COOH is the key intermediate for CO_(2)to CO.This work provides an effective method to construct multielectron transfer scheme for efficient photocatalytic CO_(2)reduction.