双功能复合材料g-C3N4/CdS/Ni催化光解水产氢和5-羟甲基糠醛氧化性能

采用高温煅烧法、 原位生长法和光还原法分三步制备出双功能复合光催化剂g-C₃N₄/CdS/Ni. 材料中CdS的引入可以增强光生电子和空穴的分离效率, Ni可以进一步提高光致产氢速率. 在以三乙醇胺(TEOA)为电子给体的水溶液中对所制备的材料进行了催化产氢性能测试, 并对材料中CdS的含量进行了优化. 结果表明, 25% (质量分数)CdS负载量的复合材料催化产氢性能最佳, 其催化产氢速率为4134.5 μmol·g^-1·h^-1, 是 g-C₃N₄/Ni催化产氢速率的115倍. 且Ni是一种良好的质子催化剂. 在此基础上, 以5-羟甲基糠醛(HMF)替代TEOA作为体系的电子给体, 其可以被选择性地催化氧化为增值化学品2, 5-二甲酰基呋喃(DFF). 当体系中HMF的转化率为82.3%, DFF的选择性为69.4%时, DFF的产率(57.2%)达到最高, 体系中H₂的产量为 51.8 μmol/g. g-C₃N₄/CdS/Ni复合材料可以在同一体系中进行催化光致产氢和HMF的选择性氧化.     

Colorimetric Detection of Glucose Using WO3 Nanosheets as Peroxidase-mimetic Enzyme

In the present work, WO₃ nanosheets(WO₃ NSs) were prepared by a facile method at room temperature. The obtained WO₃ NSs showed peroxidase-like activity, which could catalyze 3,3',5,5'-tetramethylbenzidine(TMB) to form a blue oxidation product(ox TMB) in the presence of H₂O₂. Based on this, convenient and sensitive colorimetric methods for the detection of H₂O₂ and glucose were established. The linear ranges for detecting H₂O₂ and glucose were 1-200 μmol/L and 1-100 μmol/L, respectively. The limits of the detection of H₂O₂ and glucose were as low as 0.79 and 0.96 μmol/L, respectively. This method was also successfully applied to the detection of glucose in urine samples. The detection result was consistent with that of the value detected by the clinical method, indicating the potential in clinical diagnosis and biomedical detection.     

具有过氧化物酶活性的Imm-Fe3+-IL的制备及用于比色法测定H2O2和葡萄糖

通过溶胶-凝胶法制备的Imm-Fe³⁺-IL纳米材料具有类过氧化物酶的活性,能够催化过氧化氢(H₂O₂)快速氧化3,3′,5,5′-四甲基联苯胺(TMB)产生相应的颜色变化。 稳态动力学分析表明,Imm-Fe³⁺-IL纳米材料遵循典型的Michaelis-Menten模型和乒乓机理。 辣根过氧化物酶(HRP)相比,Imm-Fe³⁺-IL纳米材料纳米材料具有更强的亲和性。 联合葡萄糖氧化酶建立了H₂O₂和葡萄糖的比色检测方法。 结果显示:H₂O₂和葡萄糖的浓度与反应体系的吸光度呈良好的线性关系,H₂O₂的线性范围为1~200 μmol/L,葡萄糖的线性范围为10~200 μmol/L,最低检出限(LOD)分别为0.35和3.31 μmol/L。     

光催化氧气还原制备H2O2

H2O2广泛应用于化工和环保领域,其分解的唯一产物是水,有利于生产与自然生态系统的协调可持续发展.工业上H2O2的合成主要是通过蒽醌法间接合成,该方法能耗大,污染环境.而直接由H2与O2混合制备H2O2,具有极大的安全风险,且需要消耗大量H2.通过光催化技术将O2和H2O转化成H2O2的方法,避免了H2与O2的直接混合...     

金属碳化钨与液相染料光敏剂协同促进光催化制氢（英文）

使用WC作为光催化材料通过水还原制氢很常见,但它通常需要与有效的光吸收剂协同才能产生有意义的光催化活性。这可归因于WC的窄带隙,导致水的氧化还原能力不足。有趣的是,我们的研究通过一种新型固液光催化体系克服了这种限制,该体系将裸WC光催化剂与液相光敏赤藓红B(Er B)相结合。这种概念的提出消除了将WC耦合到光吸收半导体的需要,这通常需要繁琐的程序来获得适当的功能化光催化复合材料。实验结果表明,在可见光(λ=520 nm)照射下,所提出的固液光催化体系产生了显著的氢气,然而,只有在三乙醇胺(TEOA)作为牺牲试剂的共同存在下。显然,仅加入WC和Er B的空白实验在典型的光催化条件下表现出几乎为零的光催化活性和无法测量的H₂生成。在光照TEOA溶液中仅存在Er B或WC的光反应中也观察到类似的活性。这些空白实验证实了所有三种成分的重要性,即WC、Er B和TEOA,它们分别作为光催化剂、光吸收剂和牺牲试剂,在我们提出的体系中产生有意义的H₂。值得注意的是,在我们的调查中系统地研究了三个关键参数,即p H值、Er B和WC浓度的影响。发现H     

Shape-controlled synthesis and photocatalytic activity of In2O3 nanostructures derived from coordination polymer precursors

In（BTC）（phen）（H₂O）nanocrystals with controllable morphology and size were successfully obtained by solvothermal method.Hierarchical straw-sheaf-like architectures,nanorods and elongated hexagons have been synthesized by varying the volume ratio of DMF:H₂O:C₂H₅OH.Phase-pure In₂O₃nanocrystals were obtained by the calcination of the precursors without significant alteration of the morphology.The products were characterized by PXRD,SEM,TEM,TGA,IR and gas adsorption measurements.The photocatalytic effect was investigated for the In₂O₃ nanocrystals with different morphology on the degradation of rhodamine B（Rh B）and it was found that the nanorods exhibited the best photocatalytic activity,which shows the degradation efficiency of 94%for 8 h.The results showed that the photocatalytic activity increased with the increase of BET surface area and pore volume.     

原位光沉积制备Z型α-Fe2O3/g-C3N4异质结及其可见光驱动光解水产氢性能

采用原位光沉积-煅烧法制得了Z型α-Fe₂O₃/g-C₃N₄异质结复合光催化剂。分别采用透射电子显微镜、X射线衍射、X射线光电子能谱、紫外可见漫反射光谱、荧光光谱以及电化学测试对样品进行了表征,并考察了可见光下光解水产氢活性。结果表明:当α-Fe₂O₃的负载量为2.9%时,α-Fe₂O₃/g-C₃N₄复合光催化剂具有最优的产氢催化活性,产氢速率高达1841.9μmol·g^-1·h^-1,约为g-C₃N₄的3.3倍。光催化性能的提高主要归因于3方面:(1)高温煅烧过程中α-Fe₂O₃的形成,有效促进了氮化碳片层的热剥离,增大了比表面积,从而为光催化反应提供了更多反应活性位;(2)超细α-Fe₂O₃颗粒(5~8 nm)高度均匀地分散在g-C₃N₄表面,并且与其紧密结合,形成了高质量的Z型异质结;(3)Z型异质结不仅有效抑制地了光生载流子的复合,同时极大地保留了g-C₃N₄导带电子的强还原性和α-Fe₂O₃价带空穴的强氧化性。     

可见光光解H2S产H2的研究——Rh2O3/CdS悬浮体系中硫化物水溶液的光解

在半导体粉末悬浮体系光解水研究中,最常用的半导体粉末是CdS和TiO₂。前者光谱响应好,可见光即可激发,但易于光腐蚀;后者稳定性好,但禁带宽,仅紫外光可激发。从不同角度改善这二者的性能,一直为人们所关注。在CdS上沉积RuO₂,并选择适宜的反应以抑制CdS的光腐蚀^[1];应用掺杂的方法,使TiO₂的光谱响应扩展至可见区,已取得进展。     

基于金属卟啉2DMOFs仿酶催化的过氧化氢比色法检测

以四(4-羧苯基)铁卟啉(FeTCPP)作为有机配体,铜离子作为金属节点,利用溶剂热法制备了双金属Cu-FeTCPP金属有机骨架(MOFs)材料,并采用表面活性剂辅助法合成了二维纳米片(Cu-FeTCPP 2DMOFs).该纳米片呈超薄的纳米结构,与三维块体结构(3DMOFs)相比具有更大的比表面积.基于Cu-FeTCPP 2DMOFs的仿酶特性,将其用于催化过氧化氢(H₂O₂)氧化底物3,3′,5,5′-四甲基联苯胺(TMB)显色,根据显色产物吸光度与H₂O₂浓度之间的正比关系实现了对H₂O₂的测定.经稳态动力学分析发现,底物相同时该纳米片的米氏常数K_m均比Cu-FeTCPP 3DMOFs的K_m小,表明纳米片与底物之间有更好的亲和力,这归因于二维结构大的比表面积和较多易接近的活性位点.基于Cu-FeTCPP 2DMOFs构建的比色检测方法在优化条件下对H₂O₂的线性检...     

MOF derived Co3O4/N-doped carbon nanotubes hybrids as efficient catalysts for sensitive detection of H2O2 and glucose

Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science.Especially,it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors.Herein,we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes(Co3O4/NCNTs)hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air.The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions.As sensor electrode,the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40μA(mmol/L)^-1 cm^-2,a linear range of 5.00μmol/L-11.00 mmol/L,and a detection limitation of 1μmol/L in H2O2 detection,and a good glucose detection performance with 5μmol/L.These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.     

微波液相法一步合成H3PW12O40/Bi2WO6光催化剂及其脱氮性能

采用微波液相法一步合成了固载型H₃PW₁₂O₄₀/Bi₂WO₆光催化剂. 通过紫外-可见漫反射光谱(UV-Vis)、 场发射扫描电子显微镜(SEM)、 表面积及孔隙度(BET)测定、 氨气程序升温脱附(NH₃-TPD)、 吡啶吸附红外光谱(Py-FTIR)和X射线衍射(XRD)对所合成催化剂的结构和性质进行了考察, 并以吡啶浓度为15 mg/g的模拟油对光催化剂的脱氮效果进行评价. 结果表明, 与传统浸渍固载法相比, 微波液相一步法不仅能高效合成H₃PW₁₂O₄₀/Bi₂WO₆光催化剂, 且所合成的催化剂能被低能量的光激发. 固载H₃PW₁₂O₄₀不但能提高Bi₂WO₆纳米颗粒的表面酸量, 还能通过改变Bi₂WO₆前驱液的酸强度来调控催化剂形貌. 在H₃PW₁₂O₄₀固载量为15%(质量分数), 微波功率为800 W, 反应时间为90 min条件下得到的H₃PW₁₂O₄₀/Bi₂WO₆的光催化脱氮活性最高, 在催化剂与模拟油质量比为1/300, 500 W氙灯光照60 min的最佳光催化反应条件下, 模拟油脱氮率达到92.63%.     

全有机S型异质结PDI-Ala/S-C3N4光催化剂增强光催化性能

Organic photocatalysts have attracted attention owing to their suitable redox band positions, low cost, high chemical stability, and good tunability of their framework and electronic structure. As a novel organic photocatalyst, PDI-Ala (N, N'-bis(propionic acid)-perylene-3, 4, 9, 10-tetracarboxylic diimide) has strong visible-light response, low valence band position, and strong oxidation ability. However, the low photogenerated charge transfer rate and high carrier recombination rate limit its application. Due to the aromatic heterocyclic structure of g-C₃N₄ and large delocalized π bond in the planar structure of PDI-Ala, g-C₃N₄ and PDI-Ala can be tightly combined through π–π interactions and N―C bond. The band structure of sulfur-doped g-C₃N₄ (S-C₃N₄) matched well with PDI-Ala than that with g-C₃N₄. The electron delocalization effect, internal electric field, and newly formed chemical bond jointly promote the separation and migration of photogenerated carriers between PDI-Ala and S-C₃N₄. To this end, a novel step-scheme (S-scheme) heterojunction photocatalyst comprising organic semiconductor PDI-Ala and S-C₃N₄ was prepared by an in situ self-assembly strategy. Meanwhile, PDI-Ala was self-assembled by transverse hydrogen bonding and longitudinal π–π stacking. The crystal structure, morphology, valency, optical properties, stability, and energy band structure of the PDI-Ala/S-C₃N₄ photocatalysts were systematically analyzed and studied by various characterization methods such as X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, X-ray photoelectron spectroscopy, ultraviolet visible diffuse reflectance spectroscopy, electrochemical impedance spectroscopy, and Mott-Schottky curve. The work functions and interface coupling characteristics were determined using density functional theory. The photocatalytic activities of the synthesized photocatalyst for H₂O₂ production and the degradation of tetracycline (TC) and p-nitrophenol (PNP) under visible-light irradiation are discussed. The PDI-Ala/S-C₃N₄ S-scheme heterojunction with band matching and tight interface bonding accelerates the intermolecular electron transfer and broadens the visible-light response range of the heterojunction. In addition, in the processes of the PDI-Ala/S-C₃N₄ photocatalytic degradation reaction, a variety of active species (h⁺, ·O₂^-, and H₂O₂) were produced and accumulated. Therefore, the PDI-Ala/S-C₃N₄ heterojunction exhibited enhanced photocatalytic performance in the degradation of TC, PNP, and H₂O₂ production. Under visible-light irradiation, the optimum 30%PDI-Ala/S-C₃N₄ removed 90% of TC within 90 min. In addition, 30%PDI-Ala/S-C₃N₄ displayed the highest H₂O₂ evolution rate of 28.3 μmol·h^-1·g^-1, which was 2.9 and 1.6 times higher than those of PDI-Ala and S-C₃N₄, respectively. These results reveal that the all organic photocatalyst comprising PDI-based supramolecular and S-C₃N₄ can be efficiently applied for the degradation of organic pollutants and production of H₂O₂. This work not only provides a novel strategy for the design of all organic S-scheme heterojunctions but also provides a new insight and reference for understanding the structure–activity relationship of heterostructure catalysts with effective interface bonding.      

Microwave-assisted One-pot Synthesis of Ag NPs/C and Its Application in H2O2 and Glucose Detection

The facile preparation of Ag NPs/C via a one-pot strategy was carried out by microwave treatment of a mixed aqueous solution of AgNO₃ and glucose at 180℃ for 20 min without the presence of extra reducing agent. The as-synthesized Ag NPs/C showed high catalytic performance toward the reduction of H₂O₂. The H₂O₂ sensor constructed with as-synthesized Ag NPs/C exhibited a short amperometric response time of less than 2 s. The linear range was approximately (0.1-50) mmol/L(r=0.997), and the detection limit was approximately 3.3 μmol/L at a signal-to-noise ratio of 3. A glucose biosensor was fabricated by immobilizing glucose oxidase onto Ag NPs/C- modified glassy carbon electrode to detect glucose. The glucose sensor had a wide linear response range of 2-22 mmol/L(r=0.999) and a detection limit of 190 μmol/L.     

TiO2/Bi2O3纳米复合体的制备及可见光催化产氢性能

首先采用相分离的水解-溶剂热法制备了Bi₂O₃纳米粒子,然后利用简单的湿化学法在Bi₂O₃表面负载不同比例的TiO₂纳米颗粒,进而得到TiO₂/Bi₂O₃纳米复合体。通过气氛调控的表面光电压谱(SPS)等测试表明,表面负载适量的TiO₂后能够提高Bi₂O₃光生电荷分离。可见光催化产氢和降解污染物测试结果进一步证明,表面负载适量的TiO₂后可显著提高其可见光催化活性,其中Ti/Bi摩尔比为7%时具有最高的光催化活性。这主要归因于TiO₂具有较为合适的导带能级位置,可以接收Bi₂O₃在可见光激发下所产生的高能级电子,从而抑制光生电子-空穴对复合,并且维持了高能级电子较高的还原能力。     

Factors influencing decomposition of H2O2 over supported Pd catalyst in aqueous medium

Since H₂O₂ decomposition can result in selectivity/yield loss in the direct H₂O₂ synthesis process from H₂ and O₂ over supported Pd catalysts, it is important to have an enhanced understanding about the factors affecting the H₂O₂ decomposition reaction. Herein, detailed studies have been undertaken to investigate the influence of different factors, such as (a) nature and concentration of acid in reaction medium, (b) nature and concentration of halide in presence and absence of acid in reaction medium, (c) pretreatment procedures and (d) catalyst modification by incorporation of different halides, on the H₂O₂ decomposition reaction over a 5% Pd/C catalyst in aqueous medium at 25 °C. This study has shown that the H₂O₂ decomposition activity is profoundly influenced by all the above factors. The effectiveness of the acids in suppressing the H₂O₂ decomposition activity decreased in the following order: hydroiodic acid > hydrobromic acid > hydrochloric acid  acetic acid > phosphoric acid > sulfuric acid > perchloric acid. The ability of the acid to decrease the H₂O₂ decomposition activity was found to very strongly depend on the nature of its associated anion. Halides, such as iodide, bromide and chloride were particularly effective in suppressing the H₂O₂ decomposition activity. Oxidation pretreatment of the catalyst was found to strongly suppress its H₂O₂ decomposition activity, while a reduction treatment was found to promote its activity. A gradual decrease in the H₂O₂ decomposition activity of the catalyst was observed with each successive usage due to in situ sub-surface oxidation of Pd by H₂O₂. Halide incorporation either via the reaction medium or prior catalyst modification had a similar qualitative effect on the H₂O₂ decomposition activity.     

反蛋白石结构ZnO@PDA用于增强光催化产H2O2性能

利用太阳能驱动生产高能量密度的H₂O₂太阳能燃料引起了广泛关注,但目前光催化剂缓慢的动力学限制了其实际应用。本文制备一种聚多巴胺(PDA)改性的反蛋白石结构ZnO(ZnO@PDA)光催化剂,用于可持续性的光催化产H₂O₂。由于电子的转移,因此当PDA与ZnO接触后,会在界面处形成一个从PDA指向ZnO的内建电场。在内建电场和能带弯曲的驱动下,ZnO导带中的光生电子与PDA最高占据分子轨道(HOMO)中的空穴复合,符合梯型异质结的电荷转移和分离途径。这种独特的梯型异质结确保了有效的电子或空穴的分离并且留存下具有强氧化还原能力的光生载流子。此外,与纯ZnO相比,反蛋白石结构的ZnO@PDA具有更强的光吸收能力。实验表明,归因于光吸收能力的提高,光生载流子的有效分离和强氧化还原能力,负载0.03% (原子分数) PDA的ZnO样品具有最佳的产H₂O₂性能(1011.4 μmol·L^-1·h^-1),分别是纯ZnO和PDA的4.4和8.9倍。     

SiO_2负载磷钨钒杂多酸杂化材料的制备及其氧化脱硫性能的研究

利用磷酸氢二钠、偏钒酸纳和钨酸钠为原料,合成了具有Keggin结构的磷钨钒杂多化合物(H5PW10V2O40),并与1-丁基-3-甲基咪唑溴(BmimBr)离子液体反应生成一种杂多酸杂化材料([Bmim]5PW10V2O40)。利用红外光谱(FT-IR)、X射线衍射光谱(XRD)和紫外可见光谱(UV-vis)对所合成的杂多酸杂化材料进行表征。结果表明,[Bmim]5PW10V2O40具有咪唑阳离子基团和Keggin型杂多阴离子基团的结构特征,并且两种基团之间存在相互作用。以SiO_2为载体制备负载型的杂多酸杂化材料催化剂[Bmim]5PW10V2O40/SiO_2,以H2O_2作为氧化剂,考察该催化剂对模拟油中DBT的氧化性能,并优化氧化反应条件,在反应温度40℃,O/S物质的量比为3.0的条件下,反应50min,模拟油品中的DBT的转化率可以达到100%。催化剂可以通过离心法分离,经过干燥之后,可以循环使用至少七次,而对DBT的氧化活性没有降低。     

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。     

助剂Ni与载体的相互作用及其对NiMo/γ-Al_2O_3催化剂加氢脱硫性能的影响

以γ-Al_2O_3为载体,制备了一系列不同NiO负载量的NiMo/γ-Al_2O_3催化剂,利用XRD、~(27)Al-MAS NMR、Py-FTIR和HRTEM等技术对其进行了表征;在高压微反装置对该系列催化剂的加氢脱硫性能进行了评价,研究了助剂Ni与载体γ-Al_2O_3中不饱和铝间的相互作用及其对催化剂活性相结构形貌和催化活性的影响。结果表明,助剂Ni优先作用于γ-Al_2O_3表面的四配位不饱和铝原子位置;随着NiO负载量的增加,硫化态NiMo/γ-Al_2O_3催化剂中MoS_2活性相的长度变短、堆垛层数增加。Ni的引入能明显提高NiMo/γ-Al_2O_3催化剂的加氢脱硫活性,但其加氢选择性则有所降低。     

NiMo/Al_2O_3-USY催化剂上中低温煤焦油加氢裂化性能研究

采用等体积浸渍法制得一系列NiMo/Al_2O_3-USY催化剂,在200 mL固定床上考察了不同金属负载量对其中低煤焦油加氢裂化催化性能的影响,进一步用NH_4F溶液改性USY以提高催化剂的脱硫性能,并结合XRD、氮气吸附-脱附、XPS、HR-TEM、H_2-TPR和NH_3-TPD等手段对催化剂进行了表征分析。结果表明,NiM o/Al_2O_3-USY催化剂适宜的M oO_3负载量为15%(质量分数);当MoO_3含量超过15%后,MoS_2活性相在载体上团聚,硫化程度趋于稳定,强酸酸量和孔径减少,增加金属负载量对煤焦油加氢裂化转化率影响较小。NH_4F改性USY可增大NiM o/Al_2O_3-USY催化剂的孔径,有利于提高煤焦油加氢裂化转化率。表面强酸酸量减少后,产品中的硫含量明显增加,说明强酸酸量是影响产物硫含量的关键因素。当NH_4F浓度为0.6 mol/L时,NH_4F改性USY制得的NM 0.6催化剂上煤焦油加氢裂化的转化率为87.65%,产品汽油馏分(≤180℃)硫含量为5.96 mg/kg,柴油馏分(180-320℃)硫含量为34.98 mg/kg。