光热协同催化甲烷二氧化碳重整反应研究进展

在光热协同催化条件下的甲烷二氧化碳重整(CRM)反应耦合了光效应和热效应，可在低温下反应生成合成气(CO和H₂),减少碳排放的同时将太阳能转化为化学能储存起来，是实现双碳目标的有效策略之一。催化剂是光热协同催化CRM反应的核心，同时调控热催化活性中心(活性金属)的结构性质和吸光材料(载体)的光学特性以及活性组分与吸光材料的协同作用，使光热协同催化剂的热催化性能及光催化性能同时得到提高，是研发高效光热协同催化剂的有效途径之一。介绍了光热协同催化CRM反应的机理及相关金属催化剂和半导体材料的研究进展，并展望了其未来发展趋势。     

共轭多孔聚合物应用于近红外光热转换材料

近红外光热转换材料在光热治疗、光驱动智能器件等医学和能源领域受到广泛重视.本文以商业化芳香小分子为单体,通过一步简单的交联聚合方法制得了四种共轭多孔聚合物,并首次系统研究了它们的光热转换性能.结果表明,它们均具有灵敏的近红外光热响应性,且材料的光热转换效率与单体结构中共轭苯环数有很大关系,其中两种聚合物的光热转换效率可...     

我国科学家在太阳能海水淡化方面取得重要突破

<正>在"纳米科技"重点专项"表面等离激元高效光热转换机理、器件及太阳能热利用"项目支持下,南京大学朱嘉教授团队将氧化铝多孔模板与金属纳米颗粒自组装技术结合,创新性地设计了一种新型吸收体材料,在400nm到10μm波段具有99%的太阳光吸收效率。结合新型界面光热转换设计,将这种材料应用到海水淡化上,光热蒸汽转化效率可达90%,并且水质可以满足WHO的饮用水标准。     

基于生物精细构型的光催化材料和光热转换材料的研究进展

目前,全球性的能源危机和环境污染问题备受关注。太阳能作为一种可再生的能源,实现其清洁、高效和低成本的转换及利用具有十分重要的意义。其中,利用光催化可将太阳能转换为可存储和运输的氢能,而通过光热效应可借助太阳能对海水进行淡化,这将有助于缓解能源短缺、环境污染以及淡水资源紧缺等问题。如何提高光能转换材料的能量转换效率是当今太阳能转换领域的关键课题。材料的性质由多种因素决定,其中构型是最重要的因素之一。因此,优良的材料构型设计成为材料、化学、生物等多学科、多领域的研究热点,以满足光电催化、光热治疗、能量转换与存储等不同领域的应用需求。然而,目前人工制备手段以"自下而上"的化学自组装与"自上而下"的物理加工方法为主,不仅成本和效率难以兼顾,更难以精准构筑具有复杂精细三维分级构型的微纳结构。对此,有学者提出"遗态材料"的概念,借鉴自然界生物体(包括微生物、动物以及植物)的精细构型,并以自然界生物体结构作为模板,制备出具有特殊结构和功能的材料。这为当今许多领域的科学研究提供了丰富的灵感和启发。近年来,基于生物精细构型的光能转换遗态材料发展迅速,在光电催化及光热领域取得了丰硕的成果。受自然界中的光合作用启发,可通过光催化反应将太阳能转换为化学能。具有三维分级结构的材料的各向异性强、反应接触面积大、微纳米孔多,能够有效增强半导体催化剂的电学、光学特性和催化性能。以树叶、蝴蝶等生物为模板的微纳多孔结构材料提高了催化剂对入射光的吸收,同时也为水分解反应提供了更多的反应位点,其产氢性能比普通构型的材料提高了数倍。同时,在光热水蒸发系统中,木材、蝶翅、莲蓬等模板由于快速的吸水能力、高效的光吸收和光增强能力以及良好的隔热性能,其与金属纳米颗粒的复合材料具有优异的光热蒸发速率与光热转换效率。本文从光催化水分解与光热水蒸发两个领域的应用方面,分别介绍了基于树叶、蝴蝶、硅藻等天然生物精细分级结构的高效太阳能转换材料的构筑及应用,对设计、制备具有分级微纳构型的光能转换材料提供一定的理论参考和借鉴意义。     

三聚氰胺海绵基高效柔性脱硝催化材料的合成及性能研究

采用两步水热法在三聚氰胺海绵碳泡沫基底(MF)上原位合成MnCo纳米阵列脱硝催化剂用于NH3选择性催化还原NOx,并研究了Co改性对Mn-MF低温性能的影响.结果表明:Co改性可以显著提高Mn-MF的低温活性、N2选择性以及抗水抗硫性能;Mn2 Co-MF催化剂具有相对最优的低温活性,在140～220℃温度区间内,其脱硝效率可达90％以上.此外,通过SEM、XRD、XPS和H2-TPR、NH3-TPD等不同表征手段探讨了Mn2 Co-MF催化剂的催化性能、氧化还原性能和结构之间的关系;Co的引入不仅可以增大催化剂的比表面积和孔容,而且还可以促进Mn2 Co-MF催化剂表面氧物种的富集,能够产生更多的酸性位点,提高催化剂的还原性,从而提高其活性.     

Mn-HAP基低温SCR催化剂的制备及抗硫中毒性能

低温选择性催化还原(SCR)脱硝是工业烟气末端治理的重要技术, 强化催化剂硫抗性是低温SCR领域内亟待解决的问题。本研究以羟基磷灰石(HAP)为载体、Mn为活性组分通过共沉淀法成功合成了Mn-HAP低温(100~200℃)脱硝催化剂, 探究了其脱硝性能及金属硫酸盐和硫酸铵的中毒特性。结果表明: 以HAP作为活性组分Mn的载体能一定程度上提高催化剂的抗硫性。当反应温度为140 ℃时, SCR催化剂脱硝效率达到100%, 金属硫酸盐相较硫酸铵对催化剂低温脱硝活性的影响更显著, 120 ℃时脱硝效率分别降低37.40%和8.83%。不同手段分析表明, 不同表面硫物种均会不同程度地降低催化剂比表面积并改变活性Mn氧化态。金属硫酸盐显著降低Mn⁴⁺/Mn比例是造成催化剂失活的主要原因。     

基于全光谱太阳光利用的光热转换材料研究进展

利用光热转换材料有效提高全光谱太阳光的利用及转换率,是目前国内外学者广泛关注的研究领域。本文综述了近年来主要研究的基于全光谱太阳光利用的光热转换材料类型及研究进展,分析了光热转换材料提高太阳光水蒸气产生效率的应用方式,介绍了太阳光水蒸气产生系统的优化设计模型,强调了低热导率的基质材料在系统中起到的作用,最后展望了光热转换材料在海水淡化领域的应用前景,并指出光热转换物理机制的深入探索和材料的规模化制备将成为未来重要的研究内容。     

光谱选择性太阳能吸收涂层的研究进展

选择性吸收涂层技术是公认的太阳能光热转换较为核心的技术,它对提高太阳能热转换效率,大规模推广太阳能光热应用起着至关重要的作用。主要综述了光谱选择性太阳能吸收涂层的分类及制备方法。     

TiO2纳米管阵列修饰优化光催化性能的研究进展

二氧化钛纳米管阵列的修饰可有效拓展其光谱响应范围,提高光催化活性的量子效率。介绍了TiO2及其修饰优化的光催化机理,详细综述了金属、非金属及化合物对TiO2纳米管阵列进行物理或化学修饰的方法以及修饰后其光催化性能的研究现状,指出了目前二氧化钛纳米管阵列研究中存在的问题,并展望了今后的研究方向。     

面向金属-空气电池和中低温固体氧化物燃料电池应用的钴基电催化剂综述

在21世纪的今天,由石油、煤炭等化石资源的过度开发与使用所引发的能源和环境问题日趋严重,开发经济、高效的能源转换与存储装置已成为新时代的研究主题。金属-空气电池和中低温固体氧化物燃料电池,作为高效的能源转换与存储装置,可以实现化学能向电能的高效转换,具有效率高、环境友好、成本低的显著优点,在过去十几年内受到了研究者的广泛关注,取得了惊人的成果。但与此同时,人们在研究中发现阴极(正极)缓慢的氧还原和氧析出反应速率极大地降低了电池转换效率,增加了应用成本,在很大程度上制约了金属-空气电池和中低温固体氧化物燃料电池的商业化发展和应用。钴基催化剂作为一种高效阴极材料,相比贵金属成本较低,且具有混合离子-电子导电性,可以有效降低极化电阻,对阴极氧还原和氧析出反应显示出高催化活性,近年来吸引了国内外学者极大的研究兴趣。对于金属-空气电池,虽然钴基催化剂如钴氧化物、尖晶石型氧化物、钙钛矿型氧化物等材料能够显著地提高金属-空气电池的电容量和循环性能,并且降低充电电压,有效降低极化,但是其催化活性和稳定性有待提高,催化机理和活性位点也需要进一步明确和探究;对于中低温固体氧化物燃料电池,钴基催化剂包括La_(1-x)Sr_xCoO_3-δ、La_(1-x)Sr_xCo_(1-y)FeyO_3-δ、Ba_(1-x)Sr_xCo_yFe_(1-y)O_3-δ和钴基双钙钛矿等材料可以大大降低阴极极化电阻和面积比电阻,提高功率密度,但是相对其他催化剂,热膨胀系数普遍较高,稳定性也较差。为了进一步提高钴基催化剂应用在金属-空气电池和中低温固体氧化物燃料电池中的催化活性,研究者采用了掺杂其他金属元素、与其他物质组成复合阴极材料以及贵金属修饰等方法,在很大程度上提高了这两种电池的性能。本文简要介绍了金属-空气电池和中低温固体氧化物燃料电池的结构、工作原理,并在此基础上着重评述了近年来面向这两种能源转换与存储器件的,包括钴氧化物、钙钛矿型氧化物、尖晶石型氧化物和双钙钛矿氧化物等在内的各种钴基电催化剂的制取、改性和性能研究探索与成果。     

Cobalt Plasmonic Superstructures Enable Almost 100% Broadband Photon Efficient CO2 Photocatalysis

The efficiency of heterogeneous photocatalysis for converting solar to chemical energy is low on a per photon basis mainly because of the difficulty of capturing and utilizing light across the entire solar spectral wavelength range. This challenge is addressed herein with a plasmonic superstructure, fashioned as an array of nanoscale needles comprising cobalt nanocrystals assembled within a sheath of porous silica grown on a fluorine tin oxide substrate. This plasmonic superstructure can strongly absorb sunlight through different mechanisms including enhanced plasmonic excitation by the hybridization of Co nanoparticles in close proximity, as well as inter- and intra-band transitions. With nearly 100% sunlight harvesting ability, it drives the photothermal hydrogenation of carbon dioxide with a 20-fold rate increase from the silica-supported cobalt catalyst. The present work bridges the gap between strong light-absorbing plasmonic superstructures with photothermal CO₂ catalysis toward the complete utilization of the solar energy.     

Highly Dispersed RuOOH Nanoparticles on Silica Spheres:An Efficient Photothermal Catalyst for Selective Aerobic Oxidation of Benzyl Alcohol

Photothermal catalysis represents a promising strategy to utilize the renewable energy source(e.g.,solar energy)to drive chemical reactions more efficiently.Successful and efficient photothermal catalysis relies on the availability of ideal photothermal catalysts,which can provide both large areas of catalytically active surface and strong light absorption power simultaneously.Such duplex requirements of a photothermal catalyst exhibit opposing dependence on the size of the catalyst nanoparticles,i.e.,smaller size is beneficial for achieving higher surface area and more active surface,whereas larger size favors the light absorption in the nanoparticles.In this article,we report the synthesis of ultrafine RuOOH nanoparticles with a size of 2–3 nm uniformly dispersed on the surfaces of silica(SiOx)nanospheres of hundreds of nanometers in size to tackle this challenge of forming an ideal photothermal catalyst.The ultrasmall RuOOH nanoparticles exhibit a large surface area as well as the ability to activate adsorbed molecular oxygen.The SiOx nanospheres exhibit strong surface light scattering resonances to enhance the light absorption power of the small RuOOH nanoparticles anchored on the SiOx surface.Therefore,the RuOOH/SiOx composite particles represent a new class of efficient photothermal catalysts with a photothermal energy conversion efficiency of 92.5%for selective aerobic oxidation of benzyl alcohol to benzylaldehyde under ambient conditions.     

Reactivating Catalytic Surface: Insights into the Role of Hot Holes in Plasmonic Catalysis

Surface plasmon resonance of coinage metal nanoparticles is extensively exploited to promote catalytic reactions via harvesting solar energy. Previous efforts on elucidating the mechanisms of enhanced catalysis are devoted to hot electron‐induced photothermal conversion and direct charge transfer to the adsorbed reactants. However, little attention is paid to roles of hot holes that are generated concomitantly with hot electrons. In this work, 13 nm spherical Au nanoparticles with small absorption cross‐section are employed to catalyze a well‐studied glucose oxidation reaction. Density functional theory calculation and X‐ray absorption spectrum analysis reveal that hot holes energetically favor transferring catalytic intermediates to product molecules and then desorbing from the surface of plasmonic catalysts, resulting in the recovery of their catalytic activities. The studies shed new light on the use of the synergy of hot holes and hot electrons for plasmon‐promoted catalysis.     

Metal-filled carbon nanotubes as a novel class of photothermal nanomaterials

Metal-filled carbon nanotubes represent a novel class of photothermal nanomaterials: when illuminated by visible light they exhibit a strong enhancement of the temperature at the metal sites, due to the enhanced plasmonic light absorption at the metal surface, which behaves as a heat radiator. Potential applications include nanomedicine, heat-assisted magnetic recording, and light-activated thermal gradient-driven devices.     

Understanding the Photothermal Conversion Efficiency of Gold Nanocrystals

Plasmon‐based photothermal therapy is one of the most intriguing applications of noble metal nanostructures. The photothermal conversion efficiency is an essential parameter in practically realizing this application. The effects of the plasmon resonance wavelength, particle volume, shell coating, and assembly on the photothermal conversion efficiencies of Au nanocrystals are systematically studied by directly measuring the temperature of Au nanocrystal solutions with a thermocouple and analyzed on the basis of energy balance. The temperature of Au nanocrystal solutions reaches the maximum at ～75°C when the plasmon resonance wavelength of Au nanocrystals is equal to the illumination laser wavelength. For Au nanocrystals with similar shapes, the larger the nanocrystal, the smaller the photothermal conversion efficiency becomes. The photothermal conversion can also be controlled by shell coating and assembly through the change in the plasmon resonance energy of Au nanocrystals. Moreover, coating Au nanocrystals with semiconductor materials that have band gap energies smaller than the illumination laser energy can improve the photothermal conversion efficiency owing to the presence of an additional light absorption channel.     

可控碳化废弃聚丙烯制备镍/碳纳米材料用于高效光蒸气转换

利用太阳能实现光蒸气转化是一项极具前景的技术,可应用于海水脱盐和淡水制备等领域.然而,从工业的角度来看,制备低成本、高效率的光热材料仍具有挑战性.本文利用聚离子液体(PIL)和氧化镍(Ni O)作为复合催化剂,实现了聚丙烯(PP)的可控碳化,并制备了镍/碳纳米材料(Ni/CNM).研究结果表明,加入微量的PIL可实现对Ni/CNM形貌和织态结构的调控.Ni/CNM由杯状碳纳米管(CS-CNT)和梨形镍纳米颗粒组成,二者在太阳光吸收上的协同作用使得Ni/CNM具有优异的光热转换性能.此外,Ni/CNM具有较高的比表面积和丰富的微/介/大孔,其构建的三维多孔网络可为水和蒸气的高效传输提供通道.光吸收高、水传输快和热导率低等优势,使Ni/CNM的水蒸发速率高达1.67 kg m^-2h^-1,光-蒸气转换效率高达94.9%,且重复使用10次后性能依然保持稳定.该材料同时适用于染料废水、海水和油/水乳化液等水质的纯化.其中,海水中金属离子的去除效率高达99.99%,染料去除率>99.9%.更重要的是,材料的光蒸气转换性能优于最新报道的碳基光热材料.此工作不仅提出了一种可将废弃聚合物转化为先进的金属/碳杂化物的可持续方法,同时也有助于太阳能利用和海水淡化领域的进一步研究.     

A Scalable Nickel–Cellulose Hybrid Metamaterial with Broadband Light Absorption for Efficient Solar Distillation

Sophisticated metastructures are usually required to broaden the inherently narrowband plasmonic absorption of light for applications such as solar desalination, photodetection, and thermoelectrics. Here, nonresonant nickel nanoparticles (diameters < 20 nm) are embedded into cellulose microfibers via a nanoconfinement effect, producing an intrinsically broadband metamaterial with 97.1% solar-weighted absorption. Interband transitions rather than plasmonic resonance dominate the optical absorption throughout the solar spectrum due to a high density of electronic states near the Fermi level of nickel. Field solar purification of sewage and seawater based on the metamaterial demonstrates high solar-to-water efficiencies of 47.9–65.8%. More importantly, the solution-processed metamaterial is mass-producible (1.8 × 0.3 m²), low-cost, flexible, and durable (even effective after 7 h boiling in water), which are critical to the commercialization of portable solar-desalination and domestic-water-purification devices. This work also broadens material choices beyond plasmonic metals for the light absorption in photothermal and photocatalytic applications.     

Second Near-Infrared Plasmonic Nanomaterials for Photoacoustic Imaging and Photothermal Therapy

Photoacoustic imaging (PAI) and imaging-guided photothermal therapy (PTT) in the second near-infrared window (NIR-II, 1000–1700 nm) have received increasing attention owing to their advantages of greater penetration depth and higher signal-to-noise ratio. Plasmonic nanomaterials with tunable optical properties and strong light absorption provide an alternative to dye molecules, showing great prospects for phototheranostic applications. In this review, the research progress in principally modulating the optical properties of plasmonic nanomaterials, especially affecting parameters such as size, morphology, and surface chemical modification, is introduced. The commonly used plasmonic nanomaterials in the NIR-II window, including noble metals, semiconductors, and heterostructures, are then summarized. In addition, the biomedical applications of these NIR-II plasmonic nanomaterials for PAI and PTT in phototheranostics are highlighted. Finally, the perspectives and challenges for advancing plasmonic nanomaterials for practical use and clinical translation are discussed.     

Harnessing the Beneficial Attributes of Ceria and Titania in a Mixed-Oxide Support for Nickel-Catalyzed Photothermal CO2 Methanation

Solar-powered carbon dioxide (CO₂)-to-fuel conversion presents itself as an ideal solution for both CO₂ mitigation and the rapidly growing world energy demand. In this work, the heating effect of light irradiation onto a bed of supported nickel (Ni) catalyst was utilized to facilitate CO₂ conversion. Ceria (CeO₂)-titania (TiO₂) oxide supports of different compositions were employed and their effects on photothermal CO₂ conversion examined. Two factors are shown to be crucial for instigating photothermal CO₂ methanation activity: ① Fine nickel deposits are required for both higher active catalyst area and greater light absorption capacity for the initial heating of the catalyst bed; and ② the presence of defect sites on the support are necessary to promote adsorption of CO₂ for its subsequent activation. Titania inclusion within the support plays a crucial role in maintaining the oxygen vacancy defect sites on the (titanium-doped) cerium oxide. The combination of elevated light absorption and stabilized reduced states for CO₂ adsorption subsequently invokes effective photothermal CO₂ methanation when the ceria and titania are blended in the ideal ratio(s).     

高光热效应碳球的快速制备及肿瘤细胞光热治疗

光热治疗是一种非侵入式的新型肿瘤治疗手段,可弥补传统治疗方式的不足。碳纳米材料作为一种高效的光热剂,在肿瘤光热治疗中表现出巨大的应用潜力。本研究采用超声辅助法使邻苯三酚与甲醛5 min快速聚合,经煅烧处理制备了单分散、粒径均一的碳球。该碳球兼具优良的细胞生物相容性和高光热转换效率。在808 nm近红外光照射下,碳球呈现良好的光热效应和光热稳定性,光热转换效率达到41.4%。细胞实验表明,碳球无明显细胞毒性,对肿瘤细胞具有显著的光热杀伤效果。制备的高光热效应碳球光热剂有望用于肿瘤光热治疗。