期刊文献+
共找到68篇文章
< 1 2 4 >
每页显示 20 50 100
Controllably partial removal of thiolate ligands from unsupported Au_(25) nanoclusters by rapid thermal treatments for electrochemical CO_(2)reduction 被引量:2
1
作者 Liting Huang Yongfeng Lun +4 位作者 Yuping Liu Liming Chen Bowen Li Shuqin Song Yi Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第11期16-22,I0002,共8页
Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,t... Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters. 展开更多
关键词 Gold nanoclusters THIOLATES Ligand removal Electrochemically active surface area Electrochemical CO_(2)reduction
下载PDF
Activation of Transition Metal(Fe,Co and Ni)-Oxide Nanoclusters by Nitrogen Defects in Carbon Nanotube for Selective CO_(2) Reduction Reaction 被引量:1
2
作者 Yi Cheng Jinfan Chen +7 位作者 Chujie Yang Huiping Wang Bernt Johannessen Lars Thomsen Martin Saunders Jianping Xiao Shize Yang San Ping Jiang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第1期253-263,共11页
The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are u... The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions. 展开更多
关键词 activation effect electrochemical CO_(2)reduction reaction N defect proton-coupled electron transfer process transition metal oxide nanocluster
下载PDF
Odd-membered cyclic hetero-polyoxotitanate nanoclusters with high stability and photocatalytic H_(2) evolution activity 被引量:1
3
作者 Ya-Jie Liu Lin Geng +2 位作者 Yao Kang Wei-Hui Fang Jian Zhang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第8期1332-1337,共6页
We investigated the hydrolysis of TiⅣ along with naturally abundant AlⅢ ions and reported the formation of a stable and semiconducting nanocluster. Interestingly, this compound exhibits an unusual odd-membered ring ... We investigated the hydrolysis of TiⅣ along with naturally abundant AlⅢ ions and reported the formation of a stable and semiconducting nanocluster. Interestingly, this compound exhibits an unusual odd-membered ring structure and also represents the largest Al-containing polyoxotitanium cluster(PTC) observed thus far. The presence of a shell of organic ligands as well as the incorporation of hetero-AlⅢ ions endowed the nanocluster with high air, thermal, and pH stabilities. The present compound exhibited a record photocatalytic hydrogen evolution of 402.88 μmol g–1 h–1 among PTC materials. This work not only paves the way towards stable PTC materials but also provides new insights into the design of novel photocatalysts. 展开更多
关键词 Polyoxotitanate Heterometallic cluster nanoclustER Water-splitting H2 production
下载PDF
Recent progress on copper catalysts with different surface states for CO_(2)electroreduction
4
作者 Wenjun Zhang Yang Yang +1 位作者 Donggang Guo Lu Liu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期10-27,I0001,共19页
The electrochemical carbon dioxide reduction reaction(eCO_(2)RR),which converts CO_(2)into various hydrocarbons or alcohols,has been extensively researched because it promises a sustainable energy economy.However,only... The electrochemical carbon dioxide reduction reaction(eCO_(2)RR),which converts CO_(2)into various hydrocarbons or alcohols,has been extensively researched because it promises a sustainable energy economy.However,only copper(Cu)can currently achieve stable and efficient hydrocarbon conversion in the eCO_(2)RR.Therefore,understanding the catalytic mechanisms and summarizing the research progress on synthesis strategies of Cu catalysts are essential for the eCO_(2)RR.This paper reviews Cu catalysts with different surface states of Cu catalysts:oxide-derived Cu,Cu nanoparticles,Cu single atoms,and Cu nanoclusters.It then reviews the development and progress of different Cu-catalyst preparation methods in recent years,focusing on the activity and selectivity of materials.Besides revealing the tendencies of catalytic selection and deep reactive mechanisms of Cu catalysts with four different surface states,this review can guide the subsequent construction of catalysts and provides an understanding of catalytic mechanisms. 展开更多
关键词 eCO_(2)RR Oxide-derived Cu Cu nanoparticles Cu single atoms Cu nanoclusters
下载PDF
金纳米团簇检测食品中NO_(2)^(–)的综合实验设计
5
作者 王松柏 董晓芮 +2 位作者 李文艳 薛柳燕 李英奇 《实验技术与管理》 CAS 北大核心 2024年第2期127-134,共8页
以金纳米团簇的合成、表征和应用为例,将纳米团簇科学前沿引入化学专业本科生综合实验教学。与国标(GB5009.33—2016)检测NO_(2)^(-)方法相比,该方法不需要对肉制品样品进行脱脂、脱蛋白等处理,检测效率显著提高,此外还对剩菜剩饭和多... 以金纳米团簇的合成、表征和应用为例,将纳米团簇科学前沿引入化学专业本科生综合实验教学。与国标(GB5009.33—2016)检测NO_(2)^(-)方法相比,该方法不需要对肉制品样品进行脱脂、脱蛋白等处理,检测效率显著提高,此外还对剩菜剩饭和多次煮沸水中的NO_(2)^(-)含量进行了检测,为健康的饮食习惯提供依据。实验涉及蛋白质变性、氧化还原反应、软硬酸碱规则、荧光传感等相关理论知识,有助于学生了解交叉学科前沿,还可以通过多模块教学,从多维度、多视角培养学生的学习兴趣以及知识迁移和综合应用能力。 展开更多
关键词 鸡蛋清 四氯金酸 金纳米团簇 NO_(2)^(–)检测 综合实验
下载PDF
荧光铜纳米团簇用于食品和环境中Cr_(2)O_(7)^(2-)的检测研究
6
作者 赵干 杨丽娜 +2 位作者 向晖 贺诗雨 刘洪林 《合肥工业大学学报(自然科学版)》 CAS 北大核心 2024年第1期112-117,共6页
重金属离子污染问题是食品和环境安全领域的一个重要课题,因此迫切需要开发科学灵敏的检测方法。文章使用4,6-二氨基-2-巯基嘧啶(DAMP)作为配体,在温和条件下,仅通过简单的搅拌,在10 min之内合成一种发射波长为590 nm的新型铜纳米团簇(c... 重金属离子污染问题是食品和环境安全领域的一个重要课题,因此迫切需要开发科学灵敏的检测方法。文章使用4,6-二氨基-2-巯基嘧啶(DAMP)作为配体,在温和条件下,仅通过简单的搅拌,在10 min之内合成一种发射波长为590 nm的新型铜纳米团簇(copper nanoclusters,CuNCs)。鉴于该团簇对于重铬酸根离子(Cr_(2)O_(7)^(2-))高度的灵敏性和抗干扰能力,将其作为荧光探针,实现了对Cr_(2)O_(7)^(2-)的特异性和灵敏性检测,最低检出限为0.7μmol/L。通过加标回收试验,验证其在饮用水和湖水实际样品中对Cr_(2)O_(7)^(2-)的荧光检测能力,荧光变化显著,其加标回收率在94.3%~108.2%之间,相对标准偏差(relative standard deviation,RSD)均低于5%。结果表明该荧光探针对食品和环境中的Cr_(2)O_(7)^(2-)具有良好的检测效果。 展开更多
关键词 食品安全 环境安全 重金属污染 铜纳米团簇(CuNCs) 重铬酸根离子(Cr_(2)O_(7)^(2-)) 荧光检测
下载PDF
Well Dispersed SnO2 Nanoclusters Preparation and Modulation of Metal-Insulator Transition Induced by Ionic Liquid
7
作者 Zhong-hu Liu Xing Chen +8 位作者 Yi-yu Zhu Si-han Zhao Zhi-qiang Wang Feng Wang Qiang-qiang Meng Lei Zhu Qin-fang Zhang Bao-lin Wang Le-le Fan 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第2期248-252,I0003,共6页
Tin dioxide (SnO2) has attracted broad interest due to its particular gas-sensor property. Nano- or atom-scale SnO2 material has always been the aim in order to ultimately improve the sensitivity. However, until now, ... Tin dioxide (SnO2) has attracted broad interest due to its particular gas-sensor property. Nano- or atom-scale SnO2 material has always been the aim in order to ultimately improve the sensitivity. However, until now, it remains difficult to synthesize SnO2 nanoclusters by using traditional methods. In the present work, we have achieved the preparation of SnO2 nanoclusters by using the cluster beam deposition technique. The obtained nanoclusters were well characterized by high resolution transmission electron microscope HR-TEM. Results indicated the formation of the well-dispersed SnO2 nanoclusters with uniform size distribution (5-7 nm). Furthermore, an obvious metal insulator transition was observed by gating with ionic liquid. Combined with theory calculation, the corresponding mechanism was systematically analyzed from oxygen vacancy induced electron doping. 展开更多
关键词 SnO2 nanoclusters Ionic liquid Oxygen vacancy Metal-insulator transition
下载PDF
Ordered mesoporous carbon spheres assisted Ru nanoclusters/RuO_(2) with redistribution of charge density for efficient CO_(2) methanation in a novel H2/CO_(2)fuel cell
8
作者 Yan Liu Tao Zhang +8 位作者 Chao Deng Shixiu Cao Xin Dai Shengwu Guo Yuanzhen Chen Qiang Tan Haiyan Zhu Sheng Zhang Yongning Liu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第9期116-124,I0004,共10页
Efficiently reducing carbon dioxide(CO_(2))into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO_(2)ncentration.In prior work,we described a unique H/CO_(2)fuel cell driven by l... Efficiently reducing carbon dioxide(CO_(2))into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO_(2)ncentration.In prior work,we described a unique H/CO_(2)fuel cell driven by low-valued waste heat,which not only CO_(2)nverts CO_(2)to methane(CH_(4))but also outputs electrical energy,yet the CO_(2)reduction rate needs to be urgently improved.Here,a novel Ru-RuOcatalyst with heterostructure was grafted on mesoporous carbon spheres by in situ partially reducing RuOinto ultrasmall Ru clusters(~1 nm),in which heteroatom-doped carbon spheres as a matrix with excellent CO_(2)nductivity and abundant pores can not only easily CO_(2)nfine the formation of Ru nanocluster but also are beneficial to the exposed active sites of Ru CO_(2)mplex and the mass transport.CO_(2)mpared to pure RuOnanoparticles supported on carbon spheres,our CO_(2)mposite catalyst boosts the CO_(2) nversion rate by more than 5-fold,reaching a value of 382.7μmol gcat.h-1at 170℃.Moreover,a decent output power density of 2.92 W mwas obtained from this H2/CO_(2)fuel cell using Ru-RuOembedded carbon spheres as a cathode catalyst.The Ru-RuOheterostructure can modify the adsorption energy of CO_(2)and induce the redistribution of charge density,thus boosting CO_(2)reduction significantly.This work not only offers an efficient catalyst for this novel H_(2)/CO_(2)fuel cell but also presents a facile method to prepare Ru nanoclusters. 展开更多
关键词 CO_(2)methanation Fuel cell Generating electricity Ru nanocluster/RuO_(2)hybrid Ordered mesoporous carbon spheres
下载PDF
External Electric Field Dependence of Optical Absorbance in SnO_2 Nanoclusters
9
作者 WANG Dehuang (Dept. of Physics, Peking University, National Laboratory for Superlattice and Microstructures, Beijing 100871, CHN) CHENG Humin, MA Jiming (Dept. of Chemistry, Peking University, Beijing 100871, CHN) 《Semiconductor Photonics and Technology》 CAS 1998年第4期256-258,共3页
The optical absorbance in near UV wavelength region in SnO 2 nanoclusters in an external electric field is determined at room temperature. The absorbance spectra as applied field and the absorbance variations with th... The optical absorbance in near UV wavelength region in SnO 2 nanoclusters in an external electric field is determined at room temperature. The absorbance spectra as applied field and the absorbance variations with the applied field are obtained.The relation between absorbance change and applied field is non-linear, and is saturated at high field region. 展开更多
关键词 ABSORBANCE External Electric Field SnO 2 nanoclusters
下载PDF
Atomically precise metal nanoclusters for(photo)electroreduction of CO_(2): Recent advances, challenges and opportunities
10
作者 Lubing Qin Guanyu Ma +1 位作者 Likai Wang Zhenghua Tang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第6期359-370,I0009,共13页
To alleviate the global warming by removing excess CO_(2) and converting them into value-added chemicals,(photo)electrochemical reduction has been recognized as a promising strategy.As the CO_(2) reduction reaction(CO... To alleviate the global warming by removing excess CO_(2) and converting them into value-added chemicals,(photo)electrochemical reduction has been recognized as a promising strategy.As the CO_(2) reduction reaction(CO_(2) RR) is involved with multiple electrons and multiple products,plus the complexity of the surface chemical environment of the catalyst,it is extremely challenging to establish the structure/function relationship.Atomically precise metal nanoclusters(NCs),with crystallographically resolved structure,molecule-like characters and strong quantum confinement effects,have been emerging as a new type of catalyst for CO_(2) RR,and more importantly,they can provide an ideal platform to unravel the comprehensive mechanistic insights and establish the structure/function relationship eventually.In this review,the recent advances regarding employing molecular metal NCs with well-defined structure including Au NCs,Au-based alloy NCs,Ag NCs,Cu NCs for CO_(2) RR and relevant mechanistic studies are discussed,and the opportunities and challenges are proposed at the end for paving the development of CO_(2) RR by using atomically precise metal NCs. 展开更多
关键词 Atomically precise metal nanoclusters (Photo)electroreduction of CO_(2) Structure/function relationship Theoretical calculations ADVANCES Opportunities and challenges
下载PDF
Au nanoclusters anchored on TiO_(2) nanosheets for high-efficiency electroreduction of nitrate to ammonia 被引量:2
11
作者 Miaosen Yang Tianran Wei +5 位作者 Jia He Qian Liu Ligang Feng Hongyi Li Jun Luo Xijun Liu 《Nano Research》 SCIE EI CSCD 2024年第3期1209-1216,共8页
Electrocatalytic nitrate reduction reaction(NO_(3)RR)offers a unique rationale for green NH_(3) synthesis,yet the lack of high-efficiency NO_(3)RR catalysts remains a great challenge.In this work,we show that Au nanoc... Electrocatalytic nitrate reduction reaction(NO_(3)RR)offers a unique rationale for green NH_(3) synthesis,yet the lack of high-efficiency NO_(3)RR catalysts remains a great challenge.In this work,we show that Au nanoclusters anchored on TiO_(2) nanosheets can efficiently catalyze the conversion of NO_(3)RR-to-NH_(3) under ambient conditions,achieving a maximal Faradic efficiency of 91%,a peak yield rate of 1923μg·h^(-1)·mgcat.-1,and high durability over 10 consecutive cycles,all of which are comparable to the recently reported metrics(including transition metal and noble metal-based catalysts)and exceed those of pristine TiO_(2).Moreover,a galvanic Zn-nitrate battery using the catalyst as the cathode was proposed,which shows a power density of 3.62 mW·cm^(-2) and a yield rate of 452μg·h^(-1)·mgcat.-1.Theoretical simulations further indicate that the atomically dispersed Au clusters can promote the adsorption and activation of NO_(3)-species,and reduce the NO_(3)RR-to-NH_(3) barrier,thus leading to an accelerated cathodic reaction.This work highlights the importance of metal clusters for the NH_(3) electrosynthesis and nitrate removal. 展开更多
关键词 NH3 electrosynthesis Zn-nitrate battery Au nanoclusters nitrate reduction reaction(NRR) TiO_(2)nanosheets
原文传递
金属纳米簇在CO_(2)光催化还原中的研究进展 被引量:3
12
作者 李春霞 贾美林 +1 位作者 郭少红 贾晶春 《分子催化》 CAS CSCD 北大核心 2023年第6期614-624,I0004,共12页
以清洁、储量丰富的太阳光作为能量来源,将二氧化碳(CO_(2))光催化还原为高附加值的化学产品是缓解当前环境和能源问题的主要方法之一.然而,CO_(2)在常温常压下非常的稳定,因此需要设计并构筑高效光催化剂来捕捉和转化CO_(2)以提高光催... 以清洁、储量丰富的太阳光作为能量来源,将二氧化碳(CO_(2))光催化还原为高附加值的化学产品是缓解当前环境和能源问题的主要方法之一.然而,CO_(2)在常温常压下非常的稳定,因此需要设计并构筑高效光催化剂来捕捉和转化CO_(2)以提高光催化CO_(2)还原的效率.在众多研究的光催化剂中,金属纳米簇因其具有独特的结构特点、优异的物理和化学性质在光催化CO_(2)还原领域得到了广泛的应用.接下来对金属纳米簇进行了分类,将金属纳米簇分为贵金属纳米簇和非贵金属纳米簇.对贵金属纳米簇和非贵金属在光催化CO_(2)还原的特点和应用做出了简单介绍与总结. 展开更多
关键词 金属纳米簇 光催化 CO_(2)还原
下载PDF
A Facile Synthesis of ZnCo2O4 Nanocluster Particles and the Performance as Anode Materials for Lithium Ion Batteries 被引量:1
13
作者 Yue Pan Weijia Zeng +7 位作者 Lin Li Yuzi Zhang Yingnan Dong Dianxue Cao Guiling Wang Brett L.Lucht Ke Ye Kui Cheng 《Nano-Micro Letters》 SCIE EI CAS 2017年第2期79-87,共9页
ZnCo_2O_4 nanocluster particles(NCPs) were prepared through a designed hydrothermal method, with the assistance of a surfactant, sodium dodecyl benzene sulfonate. The crystalline structure and surface morphology of Zn... ZnCo_2O_4 nanocluster particles(NCPs) were prepared through a designed hydrothermal method, with the assistance of a surfactant, sodium dodecyl benzene sulfonate. The crystalline structure and surface morphology of ZnCo_2O_4 were investigated by XRD, XPS, SEM, TEM, and BET analyses. The results of SEM and TEM suggest a clear nanocluster particle structure of cubic ZnCo_2O_4(*100 nm in diameter), which consists of aggregated primary nanoparticles(*10 nm in diameter), is achieved. The electrochemical behavior of synthesized ZnCo_2O_4 NCPs was investigated by galvanostatic discharge/charge measurements and cyclic voltammetry. The ZnCo_2O_4 NCPs exhibit a high reversible capacity of 700 mAh g^(-1) over 100 cycles under a current density of 100 mA g^(-1) with an excellent coulombic efficiency of 98.9% and a considerable cycling stability. This work demonstrates a facile technique designed to synthesize ZnCo_2O_4 NCPs which show great potential as anode materials for lithium ion batteries. 展开更多
关键词 ZnCo2O4 nanocluster particles Hydrothermal method Sodium dodecyl benzene sulfonate Lithium ion batteries
下载PDF
Tuning the Electrochemical Property of the Ultrafine Metal-oxide Nanoclusters by Iron Phthalocyanine as Efficient Catalysts for Energy Storage and Conversion 被引量:3
14
作者 Yi Cheng Xing Wu +3 位作者 Jean-Pierre Veder Lars Thomsen San Ping Jiang Shuangyin Wang 《Energy & Environmental Materials》 2019年第1期5-17,共13页
Nanoclusters(NCs)have been demonstrated of outstanding performance in electrochemical energy storage and conversion technologies due to their strong quantum confinement effects and strong interaction with supports.Her... Nanoclusters(NCs)have been demonstrated of outstanding performance in electrochemical energy storage and conversion technologies due to their strong quantum confinement effects and strong interaction with supports.Here,we developed a class of ultrafine metal-oxide(MOx,M=Fe,Co and Ni)NCs incorporated with iron phthalocyanine(FePc),MOx/FePc-G,supported on graphene as high-performance catalysts for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and carbon dioxide reduction(CO2RR).The high activities for ORR and OER are attributed to the electron donation and accepting ability of the highly redox active of FePc-G that could tune the properties of MOx.The FeOx/FePc-G exhibits an extremely positive half-wave potential(E1/2)of 0.888 and 0.610 V for ORR in alkaline and neutral conditions,respectively,which is around 60 mV more positive than that of Pt/C.And NiOx/FePc-G shows similar OER activity with the state-of-the-art catalysts,Ir/C,and better performance than NiFeO NCs supported on graphene.Remarkably,the CoOx/FePc-G and NiOx/FePc-G show high activity and selectivity to reduce CO2 into CO with a low onset potential of-0.22 V(overpotential is 0.11 V). 展开更多
关键词 CO2 reduction reaction iron phthalocyanine metal-oxide nanoclusters oxygen evolution reaction oxygen reduction reaction
下载PDF
无碱CO_(2)加氢高效制甲酸Pd/g-C_(3)N_(4)催化剂的单原子和纳米簇的协同作用 被引量:1
15
作者 Eun Hyup Kim Min Hee Lee +3 位作者 Jeehye Kim Eun Cheol Ra Ju Hyeong Lee Jae Sung Lee 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第4期214-221,共8页
气候变化威胁人类的生存.化石燃料的过度使用导致CO_(2)持续排放是引起全球变暖和气候变化的主要因素,须尽快减少CO_(2)排放.捕获CO_(2)并将其转化为高附加值的燃料和化学品从而循环利用是减少CO_(2)净排放的有效措施.其中,CO_(2)催化... 气候变化威胁人类的生存.化石燃料的过度使用导致CO_(2)持续排放是引起全球变暖和气候变化的主要因素,须尽快减少CO_(2)排放.捕获CO_(2)并将其转化为高附加值的燃料和化学品从而循环利用是减少CO_(2)净排放的有效措施.其中,CO_(2)催化加氢制甲酸(HCOOH)是碳捕获与利用(CCU)的有效途径之一,其产物HCOOH可用于防腐剂、牲畜饲料抗菌剂和食品添加剂,也可作为氢载体和直接甲酸燃料电池的燃料.目前,工业上生产HCOOH的工艺包括两个步骤:甲醇和CO在强碱条件下反应生成甲酸甲酯(HCO_(2)CH_(3)),随后水解为HCOOH.该工艺利用来自化石燃料的两种原料,排放出大量CO_(2),同时在水解步骤中使用了过量的酸性水,因此对生态环境产生一定的危害.近年来,以CO_(2)为可再生原料合成HCOOH被广泛研究,人们探索了电化学、光化学、生物和热化学反应等多种途径将CO_(2)还原为HCOOH,以期实现CO_(2)循环利用.上述方法距实际应用尚有一定距离,其中,CO_(2)催化加氢制HCOOH过程最先进,它与当前许多化学工业过程相似.由于CO_(2)分子的化学稳定性,CO_(2)加氢生成HCOOH在热力学上不利,可通过有机碱和无机碱形成甲酸-碱配合物,推动反应向生成HCOOH方向移动.然而,从甲酸基配合物中提取HCOOH需要额外的分离步骤,因此在无碱条件下直接将CO_(2)加氢生成HCOOH非常重要.本课题组致力于研究无碱条件下g-C_(3)N_(4)负载的Pd(记为Pd/CN)催化剂催化CO_(2)加氢合成HCOOH,前期研究(Chem.Commun.,2016,52,14302-14305和J.Catal.,2021,396,395-401)发现,通过控制Pd负载量可改变催化剂中Pd单原子/Pd纳米团簇的比例,且当两种状态Pd达到最佳比例时,催化剂催化活性最高.这表明在无碱CO_(2)加氢过程中,Pd单原子与纳米团簇间存在协同作用.此外,最近有关于单原子和纳米团簇在负载金属催化剂中不同作用的报道,如NixMg1-xO催化逆水气变换反应,Ir1/In_(2)O_(3)和Pd/Fe_(3)O_(4)催化CO_(2)加氢制乙醇反应等,这些工作得出相似的结论:单原子金属对CO_(2)活化有效,而纳米团簇对H_(2)活化有效.这对于设计以CO_(2)和H_(2)为反应物的金属催化剂很重要.本工作旨在考察类似的机理是否适用于Pd/CN催化剂在无碱条件下催化CO_(2)加氢制HCOOH过程.通过控制Pd负载量,合成了含有不同比例Pd单原子和Pd纳米团簇的Pd/CN催化剂,Pd与g-C_(3)N_(4)表面碱性位间的强静电相互作用使合成含有大量Pd单原子的Pd/CN催化剂成为可能.在Pd/CN催化剂催化无碱CO_(2)加氢制HCOOH过程中,当两种状态Pd达到最佳比例时,Pd单原子和Pd纳米簇之间存在协同作用,此时催化剂活性最高.实验表明,Pd纳米簇主要通过解离吸附参与H_(2)活化,Pd单原子对CO_(2)活化更有效.在最佳单原子比(单原子数/(单原子数+纳米簇)为41%)时,该催化剂表现出最高的活性,优于文献报道的相似反应条件下Pd催化剂活性.这些发现将为以CO_(2)和H_(2)分子为反应物的反应的催化剂设计提供一定的参考. 展开更多
关键词 无碱CO_(2)加氢制甲酸 Pd/g-C_(3)N_(4) 单原子催化剂 纳米簇催化剂 协同效应
下载PDF
基于金纳米簇和碳量子点的比率荧光传感法快速检测Hg^(2+)
16
作者 刘飞燕 赵笙良 +4 位作者 赖璇迪 陆志扬 李霖峰 韩培刚 陈丽琼 《材料导报》 CSCD 北大核心 2023年第21期82-89,共8页
汞离子(Hg^(2+))是一种致癌和无法生物降解的高毒重金属污染物,因此开发Hg^(2+)的快速检测方法对环境监测和人类健康维护具有重要意义。本研究成功构建了对Hg^(2+)快速裸眼筛查和检测的比率荧光传感器。首先采用水热合成法制备了发红色... 汞离子(Hg^(2+))是一种致癌和无法生物降解的高毒重金属污染物,因此开发Hg^(2+)的快速检测方法对环境监测和人类健康维护具有重要意义。本研究成功构建了对Hg^(2+)快速裸眼筛查和检测的比率荧光传感器。首先采用水热合成法制备了发红色荧光的金纳米簇(Gold nanoclusters,AuNCs),采用微波辅助法制备了具有高量子产率(85%)且发蓝色荧光的碳量子点(Carbon quantum dots,CDs),然后将AuNCs和CDs简单混合,构建了具有单一激发和双发射的AuNCs-CDs比率荧光传感器。基于Hg^(2+)和Au~+的高亲和嗜金属效应,Hg^(2+)可明显猝灭AuNCs-CDs中AuNCs在670 nm处的荧光发射峰,而CDs在420 nm处的参比荧光强度基本保持不变。AuNCs-CDs的比率荧光信号(I_(670)/I_(420))与在0.005~1 mg·L^(-1)范围内的Hg^(2+)浓度呈良好的线性关系,检出限为1.5μg·L^(-1)。与此同时,随着Hg^(2+)浓度的增加,AuNCs-CDs在紫外灯下的发光颜色可用裸眼明显分辨(由粉红色变为蓝色)。该方法不仅对其他金属离子具有抗干扰性,而且在河水、大米以及白菜实际样品检测中也具有可行性,加标回收率为84.5%~105.1%。因此,利用AuNCs-CDs可构建一种理想的比率荧光传感器,其可用于Hg^(2+)的快速灵敏检测,并有望真正应用到食品安全和环境检测中。 展开更多
关键词 金纳米簇(AuNCs) 碳量子点(CDs) 比率荧光传感器 快速检测 汞离子(Hg~(2+))
下载PDF
金属离子掺杂TiO_2纳米晶簇室温光透射谱 被引量:3
17
作者 梁瑞生 王德煌 +2 位作者 程虎民 王艳芹 马季铭 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 2000年第5期634-636,共3页
报道了金属离子掺杂TiO2 纳米晶簇室温光透射谱实验测量结果。金属掺杂使TiO2 纳米晶簇室温光透射值明显减小。而且 ,金属掺杂引起TiO2 纳米晶簇室温光透射值变化谱线是非线性变化曲线。在变化曲线上存在位置不等的极大值。
关键词 金属离子掺杂 室温 光透射谱 二氧化钛钠米晶簇
下载PDF
SnO_2纳米晶簇室温带隙测定 被引量:4
18
作者 王德煌 程虎民 +1 位作者 梁瑞生 唐志列 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 1997年第5期592-594,共3页
实验测定了平均直径6nm和10nm的SnO2纳米晶簇室温带隙值,得到其大小分别是3.493eV和3.307eV。
关键词 纳米晶簇 带隙 氧化锡
下载PDF
金属离子掺杂影响TiO_2纳米晶簇的光吸收(英文) 被引量:2
19
作者 王德煌 梁瑞生 +3 位作者 程虎民 马季铭 王艳芹 张冬柏 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第5期673-676,共4页
实验测量掺杂不同金属离子的TiO2 纳米晶簇在UV和可见波段的室温光吸收谱。金属离子掺杂明显增强TiO2 纳米晶簇的光吸收。TiO2 带隙发生红移。光吸收增加量随波长非线性变化。
关键词 金属离子掺杂 TiO2纳米晶簇 光吸收 二氧化钛纳米晶簇 紫外线 红移 可见光
下载PDF
气相沉积法分子筛封装SnO_2纳米半导体材料的研究 被引量:6
20
作者 张义华 郭新闻 +2 位作者 王祥生 王学勤 周卓华 《功能材料》 EI CAS CSCD 北大核心 1999年第6期651-652,共2页
以Y 型分子筛为主体,采用气相沉积法制备了分子筛封装SnO2 纳米半导体材料,并通过X 射线衍射、IR 吸收光谱、紫外漫反射光谱、TEM 等手段对不同条件下制备的样品进行了表征。对于钠型的Y 型分子筛来说,几乎无法实现有效... 以Y 型分子筛为主体,采用气相沉积法制备了分子筛封装SnO2 纳米半导体材料,并通过X 射线衍射、IR 吸收光谱、紫外漫反射光谱、TEM 等手段对不同条件下制备的样品进行了表征。对于钠型的Y 型分子筛来说,几乎无法实现有效沉积,而以交换处理后的Y 型分子筛为主体,则可以在合适的条件下,能够获得高分散的SnO2 物种,并成功地降低了对主体分子筛的破坏程度。 展开更多
关键词 气相沉积 二氧化锡 纳米粒子 分子筛 半导体
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部