超薄骨架有序介孔CdS/NiS的制备及光催化产氢性能（英文）

采用有序介孔氧化硅为硬模板,通过纳米浇筑法制备了由螺旋骨架构建的有序介孔硫化镉(CdS)光催化材料.该光催化材料具有约5 nm厚的超薄骨架和大的比表面积(238 m~2/g),能有效缩短光催化反应中光生电荷迁移到表面进行反应的距离并同时提供更多的反应活性位点,从而增强光催化性能.通过原位化学沉积法将不同量的助催化剂硫化镍(NiS)沉积到有序介孔CdS表面,得到了一系列超薄骨架有序介孔CdS/NiS复合光催化材料.可见光照射下的光催化产氢活性测试结果表明,负载适量NiS的有序介孔CdS具有显著增强的光催化产氢活性(3.84 mmol·h~(-1)·g~(-1),约为负载相同量NiS的普通商业化CdS材料(0.22 mmol·h~(-1)·g-1)的17.5 倍.     

2D-2D CdS/Cu7S4层状异质结高效可见光光催化产氢（英文）

利用太阳能将水转化为清洁可持续的化学燃料是一种很有前途的策略.光催化水分解制氢技术是有效解决能源可持续发展和环境保护问题的重要技术.CdS由于具有较窄的带隙(2.4 eV)和合适的能带位置而被认为是最有潜力的光催化水产氢催化剂之一.然而,CdS强光的腐蚀性和快速的电子空穴复合导致光催化剂活性低、稳定性差,严重阻碍了CdS光催化剂的广泛应用.为了有效提高光催化产氢活性及稳定性,人们对CdS光催化剂进行了大量改性研究.其中,合理巧妙地加载助催化剂和构造纳米结构CdS被认为是两种极为重要的改性策略,两种策略的有效耦合可以更有效地利用太阳能,实现清洁氢燃料的生成.一方面,各种形貌的CdS光催化剂均已被开发,例如纳米线、纳米棒、纳米片和量子点等.然而,由于制备工艺复杂,在以往的报道中很少有超薄2D CdS纳米片用于光催化产氢.另一方面,由于贵金属(Ag,Pt,Au)的稀缺性和高成本阻碍了其修饰光催化剂的实际应用,所以利用非贵金属助催化剂(MoSx,CuS,Ni3C,WS2,NiS,MXene,CoxP和MoP)修饰CdS提高光催化产氢活性近年来备受关注.对于地球丰富的2D层状助催化剂Cu7S4而言,具有优异的光电催化产氢活性和简单制备方法,但是在光催化产氢领域的应用上未引起足够重视.因此,本文充分利用超薄CdS纳米片以及Cu7S4纳米片各自的独特优势,构建了独特的2D-2D层状异质结,实现了高效协同光催化产氢.我们首先以乙酸镉和硫脲为原料通过一步水热法合成了超薄2D CdS纳米片,并用静电自组装方法制备了CdS/Cu7S4.在可见光下进行了产氢测试,实验结果证实了优化的2D CdS/2%Cu7S4层状异质结在含有Na2S·9H2O和Na2SO3的水溶液中光催化析氢活性最高(27.8 mmol g^-1 h^-1),是原始CdS纳米片(2.6 mmol g^-1 h^-1)的10.69倍.经过4次连续循环反应,CdS/Cu7S4二元复合体系展现出良好的稳定性.为深入探讨高效产氢机制,对纳米级CdS复合材料的光催化物化性能及载流子分离机制进行了表征.通过X射线衍射确定了CdS和CdS/Cu7S4的晶体结构.用高分辨电子显微镜和X射线光电子能谱证实合成了CdS催化剂和Cu7S4助催化剂的超薄纳米片结构且成功复合.用紫外-可见漫反射光谱法对制备的纯CdS和CdS/Cu7S4复合样品的光吸收特性进行了表征.结果表明,在CdS上负载Cu7S4以后,可以明显观察到样品对可见光的吸收能力明显增强.对CdS/Cu7S4进行XPS测试分析,进一步证明了样品中S、Cd和Cu的化学成分和状态.利用PL发射光谱研究了CdS/Cu7S4光催化剂的电荷载流子复合和转移行为.进一步对纯CdS和CdS/Cu7S4复合光催化剂的瞬态光电流响应(I-t曲线)进行了研究,确定了光生载体的分离效率.阻抗是深入研究电荷载流子迁移和界面转移的最有力技术,利用阻抗技术证实CdS/Cu7S4界面高效的载流子分离性能.极化曲线结果表明,加入Cu7S4可以降低CdS的产氢过电势,因此加速表面产氢动力学.由此可见,本文所构建的2D-2D CdS/Cu7S4二元层状异质结可以同时实现光生电子空穴对的快速分离、电子的转移和增加光生电子在表面利用效率,从而最大幅度地提高其光催化水分解产氢活性.本文所采用基于CdS纳米片的2D-2D界面耦合策略可以作为一种通用策略扩展到各种传统半导体纳米片的改性,从而极大地推进高效光催化产氢材料的持续进步.     

0D/1D碳点修饰硫化镉纳米线异质结增强可见光光催化性能（英文）

硫化镉(CdS)作为一种对可见光响应的窄带隙半导体(带隙宽度约为2.4 eV),具有合适的能带位置,近年来受到越来越多的重视.然而在光催化过程中,光生电子与空穴的快速复合极大地限制了CdS的实际应用,如何提高光生电子-空穴对的分离效率成为研究重点.一维CdS纳米棒(1D CdS NWs)具有较大的长径比,能快速有效地转移光生载流子.零维碳点(0D C-dots)是一种粒径在10 nm以下的新型纳米碳材料,其作为助催化剂能够加快光生载流子传递速率,可提高材料光催化性能.因此,通过C-dots对CdS NWs进行修饰并形成异质结,利用C-dots助催化剂的作用以提升CdS NWs的光催化性能,具有一定的可行性.本文成功构建了一种0D/1D碳点修饰CdS NWs异质结(C-dots/CdS NWs),并考察其光催化性能.通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和紫外-可见(UV-Vis)吸收光谱等技术对系列C-dots/CdS NWs样品进行表征.研究发现,C-dots成功负载在CdS NWs的表面并形成异质结.通过测试系列样品在可见光照射下光催化降解罗丹明B(RhB)以及光催化产氢性能发现,C-dots的修饰能够有效增强CdS NWs的光催化性能,其中0.4%C-dots/CdS NWs表现出最佳的光催化降解RhB活性,其经可见光照射60 min即可实现对RhB的完全降解(相同条件下CdS NWs需要180 min).同时自由基捕获实验表明,·O_2~–是降解罗丹明B过程中的主要活性基团.在光催化产氢性能测试中,0.4%C-dots/CdS NWs样品表现出最高的光催化产氢能力,产氢速率可达1633.9μmol g~(-1) h~(-1),比纯CdS的(196.9μmol g~(-1) h~(-1))提高了8.3倍,并且C-dots/CdS NWs具有良好的稳定性.研究发现,在可见光照射下,C-dots/CdS NWs能够产生较强的光生电流,且形成的0D/1D C-dots/CdS NWs异质结具有良好的电子传输能力,实现了C-dots/CdS NWs光生电子与空穴的有效分离,从而增强了光催化性能.     

Au/TiO_2/MoS_2等离子体复合光催化剂的制备及其增强光催化产氢活性

采用尿素沉积法制备了Au/Ti O_2/Mo S_2等离子体复合光催化剂。通过光催化产氢实验,在10%(φ,体积分数)甘油水溶液为牺牲剂条件下,研究了不同Mo S_2含量、Au固载2%(w,质量分数)时,Au/Ti O_2/Mo S_2(ATM)复合样品的光催化产氢活性。结果表明,当Mo S_2含量为0.1%(w)时,复合样品ATM0.1显示出最高的光催化产氢活性,其产氢速率达到708.85μmol·h~(-1),是Ti O_2/Mo S_2(TM)两相复合样品中光催化活性最高样品TM6.0产氢速率的11倍。三相复合样品显示增强光催化产氢活性主要是由于吸附在Ti O_2/Mo S_2层状复合材料上的Au纳米颗粒具有表面等离子共振效应,能强烈吸收波长范围550–560 nm的可见光,诱导产生光生电子,金纳米颗粒上的电子受到激发后转移到Ti O_2导带上,Ti O_2导带上的电子传递给片状Mo S_2,最终在Mo S_2上催化氢气产生。     

非贵金属三元复合Ni(PO3)2-Ni2P/CdS NPs异质结的构建及可见光高效催化产氢性能

结合异质结构建与共催化剂改性, 以花球状Ni(OH)₂为前驱体, 经热磷酸化后得到Ni(PO₃)₂-Ni₂P二元助催化剂, 借助超声化学合成法, 与CdS NPs复合, 形成非贵金属CdS基三元光催化材料Ni(PO₃)₂-Ni₂P/CdS NPs. 以Na₂S-Na₂SO₃为牺牲剂, 在可见光(λ＞420 nm)照射下, 在不借助任何贵金属的情况下, 负载量为8%(质量分数)的Ni(PO₃)₂-Ni₂P/CdS NPs复合材料的光催化产氢速率达到4237 μmol·g^?1·h^?1, 为CdS NPs(217 μmol·g^?1·h^?1)的19倍. 在产氢循环实验中, 反应进行到第6次循环(18 h)后, 复合材料的产氢速率约为初始的89%, 具有较好的稳定性. 与CdS NPs相比, Ni(PO₃)₂-Ni₂P/CdS NPs的吸收边明显红移, 禁带宽度降至1.86 eV, 并降低了H⁺还原的过电位, 显示出增强的光吸收性能和适宜的带隙结构. 通过Ni(PO₃)₂-Ni₂P与CdS NPs之间的协同效应, 有效促进了光生载流子的分离, 提高了产氢活性和稳定性.     

利用地球上丰富的炭黑和NiS_2双助催化剂修饰提高CdS纳米片体系的可见光产氢活性(英文)

光催化产氢技术是目前解决能源和环境问题的最有潜力的方法之一,因此制备安全高效的光催化剂已成为目前的研究热点.在目前研究的各种光催化剂中,CdS光催化剂因为具有较窄的带隙(2.4 eV)和合适的导带位置,所以在可见光催化产氢领域受到广泛关注.然而,光生电子/空穴对易复合和光腐蚀作用极大地限制了CdS光催化剂的放大应用.因此,人们采用众多改性策略以提高CdS光催化剂的可见光产氢活性,其中构建CdS纳米结构和负载助催化剂被认为是最有效的方式.构建CdS纳米结构既可以缩短载流子的迁移路径,也可以减少CdS晶体中的缺陷.很多不同纳米结构的CdS光催化剂已经被开发,例如纳米线、纳米颗粒和纳米棒等.因为制备过程极为复杂繁琐,所以CdS纳米片的研究鲜见报道.本文采用乙酸鎘和硫脲为原材料,通过简单的溶剂热法合成了CdS纳米片.在CdS的各类助催化剂中,由于常用的Pt,Ag和Au等贵金属的高成本和低储量等问题严重限制了它们的实际应用,所以近年来众多非贵金属助催化剂(例如MoS_2,WS2,NiS,NiO和WC等)得到了广泛关注.由于非贵金属助催化剂存在弱电导率和低功函数等问题,影响了对光生电子的收集和利用.纳米碳材料具有极高的电导率、强可见光吸收、有效的载流子分离和较多的反应位点等优点,因此组合纳米碳材料和非贵金属助催化剂被认为是一种有效的解决方案.本文首次采用炭黑和NiS_2作为双助催化剂改性CdS纳米片,通过简单的溶剂热/沉淀两步法成功合成了廉价高效的CdS/CB/NiS_2三元光催化体系.光催化产氢性能测试表明,CdS-0.5%CB-1%NiS_2展现出最高的光催化效率(166.7μmol h~(-1)),分别是CdS NSs和CdS-1.0%NiS_2的5.16和1.87倍.X射线衍射、高分辨电子显微镜和X射线光电子能谱结果证实了CdS催化剂的片状结构,且炭黑和NiS_2成功负载在CdS纳米片表面.紫外-可见漫反射结果表明,随着炭黑和NiS_2的负载,复合催化剂的吸收边缘产生明显的红移,且对可见光的吸收增强.荧光光谱、阻抗和瞬态光电流曲线测试结果证明,炭黑和NiS_2的加入可以有效地促进光生电子/空穴对分离.极化曲线结果表明,加入炭黑和NiS_2可以降低CdS的产氢过电势,因此加速表面产氢动力学.总之,炭黑和NiS_2之间显著的协同效应极大地提高了可见光吸收,促进光生电子/空穴对分离,加速表面产氢动力学,最终得到了三元光催化体系极高的光催化产氢活性.     

Au/N-g-C3N4复合材料的制备及其可见光催化产氢性能

首先以尿素和柠檬酸作为前驱体,通过热处理工艺合成N掺杂的g-C₃N₄(N-g-C₃N₄),然后利用化学还原的方法将Au沉积到N-g-C₃N₄表面,形成Au修饰的N掺杂的g-C₃N₄复合光催化材料(Au/N-g-C₃N₄)。通过XRD、XPS、TEM、UV-Vis和光电流测试对其进行了表征,与同等条件下制备的N-g-C₃N₄和g-C₃N₄相比,Au/N-g-C₃N₄具有更强的光吸收性能和更大的光电流。同时对材料的可见光产氢性能进行了研究,结果发现：当Au含量为1%时,复合材料呈现最佳的光催化产氢性能,其产氢速率为974μmol·g^-1·h ^-1,为N-g-C₃N₄     

超薄骨架有序介孔CdS/NiS的制备及光催化产氢性能

采用有序介孔氧化硅为硬模板, 通过纳米浇筑法制备了由螺旋骨架构建的有序介孔硫化镉(CdS)光 催化材料. 该光催化材料具有约5 nm厚的超薄骨架和大的比表面积(238 m²/g), 能有效缩短光催化反应中 光生电荷迁移到表面进行反应的距离并同时提供更多的反应活性位点, 从而增强光催化性能. 通过原位化学沉积法将不同量的助催化剂硫化镍(NiS)沉积到有序介孔CdS表面, 得到了一系列超薄骨架有序介孔CdS/NiS复合光催化材料. 可见光照射下的光催化产氢活性测试结果表明, 负载适量NiS的有序介孔CdS具有显著增强的光催化产氢活性(3.84 mmol?h^-1?g^-1), 约为负载相同量NiS的普通商业化CdS材料(0.22 mmol?h^-1?g^-1)的17.5倍.     

硫化镍修饰的硫化镉/硫化锌异质结复合光催化剂用于高效光催化产氢性质的研究(英文)

光催化水分解是一种经济而且可持续的利用太阳能来制备洁净能源氢气的方式,因此寻找和开发高效稳定的光催化剂已成为光催化产氢领域的研究热点.CdS因其具有高效、廉价、较负的导带位置等优点而引起人们的关注.然而,由于CdS镉本身光生电子/空穴对易复合,以及存在光腐蚀等不足,限制了其实际利用.为了提高CdS的光催化水分解产氢性质,人们开发了构建异质结和负载助催化剂等策略.近年来,ZnO,g-C_3N_4,TiO_2等半导体已被证实可以与CdS一起形成Ⅱ型异质结来促进光生电子和空穴的分离,进而提升光催化产氢性质.此外,传统的type Ⅰ型CdS/ZnS异质结也被证实能提高光催化产氢速率.研究表明,ZnS一方面能够钝化CdS表面态,另一方面ZnS半导体中存在缺陷能(VZn,IS),有利于转移CdS价带的空穴,最终大幅度提高了整个体系的光催化活性.在适用于CdS的各种助催化剂中,由于常用的Pt,Pd和Ru等贵金属的高成本严重限制了它们的实际应用,所以近年来基于过渡金属的各种非贵金属助催化剂(包括MoS_2,Ni_2P,FeP,Ni_3N,NiS,Ni(OH)_2等)得到了广泛的研究.我们采用原位化学沉积法将无定型的NiS助催化剂修饰在CdS/ZnS异质结表面,开发出廉价高效的NiS-CdS/ZnS三元产氢光催化体系.在该三元体系中,NiS和ZnS分别用于促进CdS导带上光生电子和价带的光生空穴的分离及利用,从而使得高能的CdS的光生电子转移到NiS表面并应用于光催化产氢,而高能的CdS的光生空穴被应用于氧化牺牲剂Na2S和Na_2SO_3,最终实现了整个体系的高效光催化产氢活性及稳定性.我们首先利用水热合成法得到大量的CdS纳米棒,然后使用化学浴沉积法在CdS表面沉积一定量的ZnS壳层,制备出CdS/ZnS异质结.光照前,采用原位化学沉积法将NiS颗粒负载在CdS/ZnS表面.光催化产氢的性能测试表明,当初始加入镍盐(20 mmol/L)量为100μL时,所得样品N2(NiS-CdS/ZnS)产氢效率最高(574μmol·h~(–1)),分别是CdS/NiS,CdS/ZnS和CdS的16.2,5.6和38倍.复合材料的表观量子效率高达43.2%.由此可见,NiS助催化剂和CdS/ZnS异质结存在协同效应,实现了三元体系的高效的光催化产氢性能.瞬态光电流测试结果表明,ZnS和NiS的加入能有效地促进光生电子/空穴的分离和利用.X射线衍射结果表明,CdS以六方相的形式存在,负载ZnS和NiS之后没有明显变化.高分辨透射电子显微镜照片和元素分布证实了NiS-CdS/ZnS复合材料中ZnS和NiS富集在纳米棒表层,其中NiS没有明显晶格条纹.紫外-可见漫反射结果表明,NiS和ZnS的负载后,复合材料的吸收边和纯相的CdS相近,而加入NiS助催化剂使得复合催化剂的颜色变黑,进而增加了可见光的吸收.     

非贵金属助催化剂CoP增强CdS纳米棒的光催化产氢活性研究

开发高效、廉价的非贵金属助催化剂一直是光催化分解水产氢领域备受关注的研究热点．本文采用水热和煅烧法合成非贵金属CoP负载的CdS纳米棒复合光催化材料．当CoP负载的质量分数为15%时,CoP/CdS复合光催化剂的产氢性能最优,达4 729.38μmol·g^-1·h^-1,是单一CdS的83倍．产氢测试结果表明,CoP作为助催化剂可以有效地提升光生载流子的分离效率,从而提高光催化产氢性能．此外,本文还重点研究助催化剂CoP与CdS之间光生载流子分离、传输行为以及复合比例对CdS光催化产氢活性的影响规律及其光催化产氢活性增强机理．本工作为设计开发低成本、高效的光催化材料提供了新的策略．     

Fabrication of ZnS/CdS Heterojunction by Using Bimetallic MOFs Template for Photocatalytic Hydrogen Generation

A new ZnS/CdS heterojunction is constructed through the direct sulfurization of a metal ions exchanged Zn/Cd-MOF precursor(MOF=metal-organic framework material). The composition, structure, morphology, photo-absorption and photoelectric performance of the ZnS/CdS are characterized by powder X-ray diffraction(PXRD), scanning electron microscope(SEM), transmission electron microscope(TEM), diffuse reflection spectrum(DRS), photoelectric current(PEC), electrochemical impedance spectroscopy(EIS) and photoluminescence(PL) technologies. Since the metal ions are highly orderly separated by the organic ligands and the inherent porosity of the Zn/Cd-MOF, the as-synthesized ZnS/CdS possesses a large surface area and intimate contact at the heterogeneous interface with uniform ZnS/CdS nanoparticles. The photocatalytic hydrogen evolution activity of the ZnS/CdS is investigated under visible light irradiation(λ ≥ 420 nm). It exhibits enhanced photocatalytic performance that the optimal ZnS/CdS achieves a maximum average hydrogen production rate of 2348 μmol·h^-1·g^-1. A possible electron transfer mechanism is therefore proposed by the analyses of the Mott-Schottky plots.     

多壁碳纳米管修饰的CdS/TiO2复合光催化材料的制备及其光解水制氢特性

以P25 TiO₂(德国Degussa化学公司)粉末为原料采用溶胶-凝胶法制备了含有不同CdS质量分数的复合光催化剂,利用多壁碳纳米管(MWCNTs)对CdS/TiO₂进行修饰,制备了一系列不同CdS含量的MWCNTs/CdS/TiO₂光催化材料。对所得的光催化剂进行了扫描电镜、低温氮吸附-脱附及光解水制氢活性的表征。研究了MWCNTs对CdS/TiO₂催化剂体系光解水制氢活性的影响。结果表明,MWCNTs的引入均使得光解水产氢量(14.0 μmol)增加,与未加入MWCNTs的复合光化剂产氢量(11.6 μmol)相比,平均产氢率增加了18%,最高可达21%。     

Highly efficient visible-light-driven photocatalytic hydrogen production of CdS-cluster-decorated graphene nanosheets

The production of clean and renewable hydrogen through water splitting using photocatalysts has received much attention due to the increasing global energy crises. In this study, a high efficiency of the photocatalytic H(2) production was achieved using graphene nanosheets decorated with CdS clusters as visible-light-driven photocatalysts. The materials were prepared by a solvothermal method in which graphene oxide (GO) served as the support and cadmium acetate (Cd(Ac)(2)) as the CdS precursor. These nanosized composites reach a high H(2)-production rate of 1.12 mmol h(-1) (about 4.87 times higher than that of pure CdS nanoparticles) at graphene content of 1.0 wt % and Pt 0.5 wt % under visible-light irradiation and an apparent quantum efficiency (QE) of 22.5% at wavelength of 420 nm. This high photocatalytic H(2)-production activity is attributed predominantly to the presence of graphene, which serves as an electron collector and transporter to efficiently lengthen the lifetime of the photogenerated charge carriers from CdS nanoparticles. This work highlights the potential application of graphene-based materials in the field of energy conversion.     

CdS Reinforced with CoSX/NiCo-LDH Core-shell Co-catalyst Demonstrate High Photocatalytic Hydrogen Evolution and Durability in Anhydrous Ethanol

At present, inefficient charge separation of single photocatalyst impedes the development of photocatalytic hydrogen evolution. In this work, the CoS_X/NiCo-LDH core-shell co-catalyst was cleverly designed, which exhibit high activity and high stability of hydrogen evolution in anhydrous ethanol system when coupled with CdS. Under visible light (λ≥420 nm) irradiation, the 3 %Co/NiCo/CdS composite photocatalyst exhibits a surprisingly high photocatalytic hydrogen evolution rate of 20.67 mmol g⁻¹ h⁻¹, which is 59 times than that of the original CdS. Continuous light for 20 h still showed good cycle stability. In addition, the 3 %Co/NiCo/CdS composite catalyst also shows good hydrogen evolution performance under the Na₂S/Na₂SO₃ and lactic acid system. The fluorescence (PL), ultraviolet-visible diffuse reflectance (UV-vis) and photoelectrochemical tests show that the coupling of CdS and CoS_X/NiCo-LDH not only accelerates the effective transfer of charges, but also greatly increases the absorption range of CdS to visible light. Therefore, the hydrogen evolution activity of the composite photocatalyst has been significantly improved. This work will provide new insights for the construction of new co-catalysts and the development of composite catalysts for hydrogen evolution in multiple systems.     

Gold/monolayer graphitic carbon nitride plasmonic photocatalyst for ultrafast electron transfer in solar-to-hydrogen energy conversion

Gold (Au) plasmonic nanoparticles were grown evenly on monolayer graphitic carbon nitride (g-C₃N₄) nanosheets via a facile oil-bath method. The photocatalytic activity of the Au/monolayer g-C₃N₄ composites under visible light was evaluated by photocatalytic hydrogen evolution and environmental treatment. All of the Au/monolayer g-C₃N₄ composites showed better photocatalytic performance than that of monolayer g-C₃N₄ and the 1% Au/monolayer g-C₃N₄ composite displayed the highest photocatalytic hydrogen evolution rate of the samples. The remarkable photocatalytic activity was attributed largely to the successful introduction of Au plasmonic nanoparticles, which led to the surface plasmon resonance (SPR) effect. The SPR effect enhanced the efficiency of light harvesting and induced an efficient hot electron transfer process. The hot electrons were injected from the Au plasmonic nanoparticles into the conduction band of monolayer g-C₃N₄. Thus, the Au/monolayer g-C₃N₄ composites possessed higher migration and separation efficiencies and lower recombination probability of photogenerated electron-hole pairs than those of monolayer g-C₃N₄. A photocatalytic mechanism for the composites was also proposed.     

One-pot hydrothermal synthesis of willow branch-shaped MoS2/CdS heterojunctions for photocatalytic H2 production under visible light irradiation

Willow branch-shaped MoS₂/CdS heterojunctions are successfully synthesized for the first time by a facile one-pot hydrothermal method. The as-prepared samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption measurements, diffuse reflectance spectroscopy, and photoelectrochemical and photoluminescence spectroscopy tests. The photocatalytic hydrogen evolution activities of the samples were evaluated under visible light irradiation. The resulting MoS₂/CdS heterojunctions exhibit a much improved photocatalytic hydrogen evolution activity than that obtained with CdS and MoS₂. In particular, the optimized MC-5 (5 at.% MoS₂/CdS) photocatalyst achieved the highest hydrogen production rate of 250.8 μmol h^-1, which is 28 times higher than that of pristine CdS. The apparent quantum efficiency (AQE) at 420 nm was 3.66%. Further detailed characterizations revealed that the enhanced photocatalytic activity of the MoS₂/CdS heterojunctions could be attributed to the efficient transfer and separation of photogenerated charge carriers resulting from the core-shell structure and the close contact between MoS₂ nanosheets and CdS single-crystal nanorods, as well as to increased visible light absorption. A tentative mechanism for photocatalytic H₂ evolution by MoS₂/CdS heterojunctions was proposed. This work will open up new opportunities for developing more efficient photocatalysts for water splitting.     

Enhancement of photocatalytic H2 evolution on CdS by loading MoS2 as Cocatalyst under visible light irradiation

This communication presents our recent results that the activity of photocatalytic H2 production can be significantly enhanced when a small amount of MoS2 is loaded on CdS as cocatalyst. The MoS2/CdS catalysts show high rate of H2 evolution from photocatalytic re-forming of lactic acid under visible light irradiation. The rate of H2 evolution on CdS is increased by up to 36 times when loaded with only 0.2 wt % of MoS2, and the activity of MoS2/CdS is even higher than those of the CdS photocatalysts loaded with different noble metals, such as Pt, Ru, Rh, Pd, and Au. The junction formed between MoS2 and CdS and the excellent H2 activation property of MoS2 are supposed to be responsible for the enhanced photocatalytic activity of MoS2/CdS.     

一维硫化镉/二维二硫化钨纳米异质结用于超高活性光催化制氢

基于半导体的太阳能光催化分解水制氢技术是一种环境友好、潜力巨大的绿色氢能制造方案.常用的块体半导体材料一般具有较弱的可见光吸收、快速的光生载流子复合以及较低的光催化制氢效率等缺点.因此,设计开发具有宽光谱光吸收、稳定性好、催化活性高的太阳能光催化材料是促进光催化制氢发展的关键,也是该研究方向的挑战之一.硫化镉纳米材料是...     

Preparation of SiO2-Pt-CdS composite photocatalyst and its photocatalytic activity for hydrogen evolution under visible light

CdS nanoparticles were prepared by the precipitation method. Pt was loaded on CdS by photodeposition. SiO₂-Pt-CdS was synthesized via hydrolysis of tetraethylorthosilicate in the presence of Pt-CdS. The samples were characterized by XRD, BET, PL and UV-Vis techniques. The photocatalytic activity of the samples for hydrogen evolution was investigated under visible light irradiation (λ ≥ 420 nm). The stability and activity of CdS was improved by coating SiO₂.