氧化镓纳米带的合成和发光性质研究

采用化学气相沉积法，以碳纳米管作还原剂还原Ga₂O₃粉末，生成的气态Ga₂O和载气Ar中的微量O₂反应，在多孔氧化铝模板上沉积得到了Ga₂O₃纳米带。用扫描电子显微镜，透射电子显微镜和选区电子衍射对产物的结构和形态进行表征，发现产物为β-Ga₂O₃纳米带，宽度在20～500 nm之间，厚度为5～100 nm，长度可达几十微米。产物中还有几微米宽的Ga₂O₃纳米片。光致发光谱结果表明β-Ga₂O₃纳米带能发射蓝光和紫外光。文中还简单推测了β-Ga₂O₃纳米带的形成机理。     

磷化镍修饰磷掺杂氧化镓可见光催化水分解产氢

以Ga₂O₃半导体为前驱体,用浸渍加低温磷化法制备了P掺杂Ga₂O₃表面修饰Ni₂P光催化剂(x-Ni₂P/Ga₂O₃-P_y,x代表Ni²⁺和Ga₂O₃的物质的量之比,y代表NaH₂PO·H₂O与Ga₂O₃的物质的量之比)。5%-Ni₂P/Ga₂O₃-P₆催化剂展现出在纯水中光催化析氢的高活性,在430 nm光照下的光量子效率为0.22%。机理研究结果表明Ni₂P修饰和P掺杂扩展了催化剂的光响应范围,同时提升了载流子分离迁移效率,其长周期光催化反应稳定性明显优于未磷化催化剂。     

磷化镍修饰磷掺杂氧化镓可见光催化水分解产氢

以Ga₂O₃半导体为前驱体,用浸渍加低温磷化法制备了P掺杂Ga₂O₃表面修饰Ni₂P光催化剂(x-Ni₂P/Ga₂O₃-P_y,x代表Ni²⁺和Ga₂O₃的物质的量之比,y代表NaH₂PO·H₂O与Ga₂O₃的物质的量)。5%-Ni₂P/Ga₂O₃-P₆催化剂展现出在纯水中光催化析氢的高活性,在430 nm光照下的光量子效率为0.22%。机理研究结果表明Ni₂P修饰和P掺杂扩展了催化剂的光响应范围,同时提升了载流子分离迁移效率,其长周期光催化反应稳定性明显优于未磷化催化剂。     

BiOBr/g-C3N4 S型异质结无H2O2光-自芬顿高效催化降解RhB

通过焙烧-超声混合法成功地制备了BiOBr/g-C₃N₄ S型异质结复合光催化剂。采用多种表征手段对样品物理属性进行了表征,包括X射线多晶粉末衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外可见漫反射光谱(UV-VisDRS)。研究了所制备样品有/无Fe³⁺的光-自芬顿催化/光催化降解罗丹明B (RhB)性能。通过捕获实验确定了光催化反应中的主要活性物种,提出了光-自芬顿反应的降解机理。研究结果表明,BiOBr/g-C₃N₄ S型异质结能原位生成H₂O₂,添加Fe³⁺后,H₂O₂被原位活化成活性物种且光生电流和载流子分离效率获得显著提高。该光-自芬顿过程能高效降解RhB,其反应速率常数为0.208 min^-1,约为无Fe³⁺光催化反应速率常数的5.3倍,在光-自芬顿循环使用过程中表现出良好的稳定性。Fe³⁺的加入促进了光生电荷的分离和H₂O₂的活化,超氧阴离子自由基(·O₂^-)、空穴和羟基是光-自芬顿催化过程中的主要活性物种,且·O₂^-作用更大。     

Ti3+自掺杂的TiO2(A)/TiO2(R)/In2O3纳米异质结的制备与可见光催化性能

以TiCl₃和InCl₃为Ti源和In源,在不使用还原剂的条件下,首先通过液相沉淀反应制备前驱体沉淀,然后采用后续水热处理制备Ti³⁺自掺杂的TiO₂(A)/TiO₂(R)/In₂O₃纳米异质结,考察了水热处理温度对材料结构和性能的影响。利用X射线衍射、透射电子显微镜、X射线光电子能谱和紫外-可见漫反射光谱对样品进行表征。分别以罗丹明B和苯酚溶液为模拟废水评价了样品的可见光催化降解性能。结果表明,与纯的TiO₂、In₂O₃以及Ti³⁺自掺杂的TiO₂相比,Ti³⁺自掺杂的TiO₂(A)/TiO₂(R)/In₂O₃纳米异质结在可见光区有明显的吸收,并具有良好的可见光催化降解性能,200℃下水热处理24 h所得样品光催化降解罗丹明B的反应速率常数(0.0444 min^-1)分别是纯TiO₂和In₂O₃的17.76倍和8.71倍。瞬态光电流时间响应结果表明样品的光催化性能主要来源于TiO₂(A)/TiO₂(R)/In₂O₃纳米异质结导致的提高的光生电子和空穴分离效率。     

p区金属氧化物Ga2O3和Sb2O3光催化降解盐酸四环素性能差异

对沉淀法合成的p区金属氧化物Ga₂O₃和Sb₂O₃紫外光光催化降解盐酸四环素的性能进行了研究,讨论了制备条件对光催化性能的影响。最佳制备条件下得到的Ga₂O₃-900和Sb₂O₃-500样品光催化性能存在巨大差异,通过X射线粉末衍射、傅里叶红外光谱、N₂吸附-脱附测试、荧光光谱、拉曼光谱、电化学分析及活性物种捕获实验等对样品进行分析,研究二者光催化降解盐酸四环素的机理,揭示影响光催化性能差异的本质因素。结果表明,Ga₂O₃和Sb₂O₃光催化性能差异主要归结于二者不同的电子和晶体结构、表面所含羟基数量及光催化降解机理。     

Co3O4/ZnO修饰针灸针的制备及其在葡萄糖检测领域的应用

将Co₃O₄/ZnO针状纳米棒材料修饰到针灸针表面用于检测葡萄糖浓度的变化。首先采用水热法在针灸针表面得到Co（CO₃）_0.5（OH）·0.11H₂O针状纳米棒前驱体,然后在500 ℃条件下退火3 h得到Co₃O₄针状纳米棒阵列。再采用浸渍法将预制备好的ZnO量子点修饰到Co₃O₄针状纳米棒表面,得到Co₃O₄/ZnO复合修饰的针灸针。研究发现此针灸针对葡萄糖具有较好的电流响应（2 264.27 μA·L·mmol^-1·cm^-2）、较快的响应速度（<4 s）及较低的检测极限（0.311 μmol·L^-1（S/N=3））。且该针灸针在用于检测人体模拟细胞液中葡萄糖浓度时,对抗坏血酸和尿素等表现出较强的抗干扰性。     

Co3O4/ZnO修饰针灸针的制备及其在葡萄糖检测领域的应用

将Co₃O₄/ZnO针状纳米棒材料修饰到针灸针表面用于检测葡萄糖浓度的变化。首先采用水热法在针灸针表面得到 Co（CO₃）_0.5（OH）·0.11H₂O针状纳米棒前驱体,然后在500 ℃条件下退火3 h得到Co₃O₄针状纳米棒阵列。再采用浸渍法将预制备好的ZnO量子点修饰到Co₃O₄针状纳米棒表面,得到Co₃O₄/ZnO复合修饰的针灸针。研究发现此针灸针对葡萄糖具有较好的电流响应（2 264.27 μA·L·mmol^-1·cm^-2）、较快的响应速度（<4 s）及较低的检测极限（0.311 μmol·L^-1（S/N=3））。且该针灸针在用于检测人体模拟细胞液中葡萄糖浓度时,对抗坏血酸和尿素等表现出较强的抗干扰性。     

同轴静电纺丝技术制备Y2O3:Eu3＋@SiO2豆角状纳米电缆与表征

采用同轴静电纺丝技术, 以氧化钇、氧化铕、正硅酸乙酯(C₈H₂₀O₄Si)、无水乙醇、PVP和DMF为原料, 成功制备出大量的Y₂O₃:Eu^3＋@SiO₂豆角状纳米电缆. 用TG-DTA, XRD, SEM, TEM和荧光光谱等分析技术对样品进行了系统地表征． 结果表明, 得到的产物为Y₂O₃:Eu^3＋@SiO₂豆角状纳米电缆, 以无定型SiO₂为壳层, 晶态Y₂O₃:Eu^3＋球为芯, 电缆直径约为200 nm, 内部球平均直径约150 nm, 壳层厚度约为25 nm, 电缆长度＞300 μm. 纳米电缆内部为球状结构, 沿着纤维长度方向有序排列, 形貌均一. Y₂O₃:Eu^3＋@SiO₂豆角状纳米电缆在246 nm紫外光激发下, 发射出Eu^3＋离子特征的波长为614 nm的明亮红光. 对其形成机理进行了初步讨论.     

Li1.2Mn0.54Ni0.13Co0.13O2正极材料的Ga2O3包覆改性及电化学性能

首先采用共沉淀方法制备富锂锰基正极材料 Li_1.2Mn_0.54Ni_0.13Co_0.13O₂原始样品(P-LRMO), 然后通过简单的湿化学法以及低温煅烧方法对其进行不同含量 Ga₂O₃原位包覆。透射电子显微镜(TEM)以及 X射线光电子能谱(XPS)结果表明在 P-LRMO表面成功合成了 Ga₂O₃包覆层。电化学测试结果表明:含有 3 %Ga₂O₃的改性材料 G3-LRMO具有最优的电化学性能, 其在 0.1C倍率(电流密度为 25 mA·g^-1)下首圈充放电比容量可以达到 270.1 mAh·g^-1, 在 5C倍率下容量仍能保持 127.4 mAh·g^-1, 优于未改性材料的 90.7 mAh·g^-1, 表现出优异的倍率性能。G3-LRMO在 1C倍率下循环 200圈后仍有 190.7 mAh·g^-1的容量, 容量保持率由未改性前的 72.9 %提升至 85.6 %, 证明 Ga₂O₃包覆改性能有效提升富锂锰基材料的循环稳定性。并且, G3-LRMO在 1C倍率下循环 100圈后, 电荷转移阻抗(R_ct)为 107.7 Ω, 远低于未改性材料的 251.5 Ω, 表明 Ga₂O₃包覆层能提高材料的电子传输速率。     

Photocatalytic performance of combustion-synthesized β and γ-Ga2O3 in the degradation of 1,4-dioxane in aqueous solution

Nanostructures of β and γ-Ga₂O₃ were prepared by the solution combustion route using urea as fuel. The synthesized nano photocatalysts were characterized by use of XRD, FT-IR, BET, TEM, TGA–DTA, DRS, and Raman spectroscopy. XRD and TEM investigations confirmed the nanostructures; particle size was in the range 3–5 nm for γ-Ga₂O₃ and 40–50 nm for β-Ga₂O₃. The specific surface area of γ-Ga₂O₃ was 91 m² g^?1 and that of β-Ga₂O₃ was 24.3 m² g^?1. The polymorphs of gallium oxide were used as photocatalysts for decomposition of 1,000 mg/l 1,4-dioxane. More than 90 % of the 1,4-dioxane could be degraded in less than 180 min by use of 10 mg/l photocatalyst + 0.5 ml H₂O₂. The efficiency of photocatalytic degradation of 1,4-dioxane by the synthesized photocatalysts was compared with that of P-25 TiO₂ and followed the order γ-Ga₂O₃ ≥ β-Ga₂O₃ > P-25 TiO₂. The degradation was found to follow pseudo first-order kinetics.     

SnO2/TiO2纳米管复合光催化剂的性能及失活再生

基于微波水热法和微乳液法合成SnO₂/TiO₂纳米管复合光催化剂. 通过X射线衍射（XRD）、配有能量色散X射线光谱仪（EDX）的透射电镜（TEM）和电化学手段对光催化剂进行表征. 以甲苯为模型污染物,考察光催化剂在紫外光（UV）和真空远紫外光（VUV）下的性能及失活再生. 结果表明,SnO₂/TiO₂纳米管复合光催化剂形成三元异质结（锐钛矿相TiO₂（A-TiO₂）/金红石相TiO₂（R-TiO₂）、A-TiO₂/SnO₂和R-TiO₂/SnO₂异质结）,促使光生电子-空穴对的有效分离,提高光催化活性. SnO₂/TiO₂表现出最佳的光催化性能,UV和VUV条件下的甲苯降解率均达100%,CO₂生成速率（k₂）均为P25的3倍左右. 但由于UV光照矿化能力不足,中间产物易在催化剂表面累积. 随着UV光照时间的增加,SnO₂/TiO₂逐渐失活,20 h 后k₂由138.5 mg·m^-3·h^-1下降到76.1 mg·m^-3·h^-1. 利用VUV再生失活的SnO₂/TiO₂,过程中产生的·OH、O₂^-·、O（¹D）、O（³P）、O₃等活性物质可氧化吸附于催化剂活性位的难降解中间产物,使催化剂得以再生,12 h后k₂恢复到143.6 mg·m^-3·h^-1. UV和VUV的协同效应使UV降解耦合VUV再生成为一种可持续的光催化降解污染物模式.     

立方Nd2O3上过氧物种光诱导生成的18O同位素示踪考察

采用原位显微Raman光谱和¹⁸O同位素示踪技术,以325 nm激光为激发光源,对立方Nd₂O₃上过氧物种的光诱导生成过程进行了详细表征,进一步证实过氧源于分子氧对晶格氧的氧化反应. 结果还表明,325 nm激光在室温下即可诱导过氧的生成,在实验条件下,生成的过氧物种可与Nd₂O₃的晶格氧发生快速的氧交换反应,位于Nd₂O₃体相的晶格氧也可迁移至样品表层进而参与过氧的生成. 325 nm激光照射有助于促进晶格氧的迁移以及晶格氧与分子氧之间的氧交换反应.     

Enhanced Photocatalytic Performance of rGO Modulated β-Ga2O3 for Wastewater Treatment

Rapid urbanization has inevitably raised challenges by indirectly adding industry waste to the environment. This problem becomes even more severe when contamination of consumable water is considered. As a leading sector in semiconductor-related research to face such challenges, gallium oxide and its derivatives have shown remarkable performance by exhibiting controlled, recyclable photocatalytic activities. This work demonstrates the enhancement of the photocatalytic performance of β-Ga₂O₃, which is related to the structural and morphological variation induced by rGO wrapping. Firstly, the Ga₂O₃ nanostructures are obtained by calcinating gallium oxide hydroxide (GaOOH), which is synthesized via a simple chemical route. On the other hand, rGO wrapped β-Ga₂O₃ is synthesized using in-situ hydrothermal treatment. In addition to traditional characterizations such as X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, etc., the photocatalytic performance of both pristine and composite systems is studied by time-dependent UV–Vis absorption spectrum for the degradation of different organic toxic pollutants. It is observed that the composite sample exhibited a larger effective surface area and enhanced optical absorption in the UV–Vis range as compared to the pristine gallium oxide sample. Under UV light irradiation, the rGO wrapped β-Ga₂O₃ nanobars can degrade rhodamine B dye entirely within 25 min and exhibit a higher photodegradation rate of 0.1598 min⁻¹ which became 3.5 times higher as compared to that of pure gallium oxide.     

Vacuum‐UV Irradiation‐Based Formation of Methyl‐Si‐O‐Si Networks from Poly(1,1‐Dimethylsilazane‐co‐1‐methylsilazane)

The vacuum‐UV (VUV)‐induced conversion of commercially available poly(1,1‐dimethylsilazane‐co‐1‐methylsilazane) into methyl‐Si‐O‐Si networks was studied using UV sources at wavelengths around 172, 185, and 222 nm, respectively. Time‐of‐flight secondary ion mass spectroscopy (TOF‐SIMS), X‐ray photo electron spectroscopy (XPS), and Fourier transform infrared (FTIR) measurements, as well as kinetic investigations, were carried out to elucidate the degradation process. First‐order kinetics were found for the photolytically induced decomposition of the Si? NH‐Si network, the subsequent formation of the methyl‐Si‐O‐Si network and the concomitant degradation of the Si? CH₃ bond, which were additionally independent of the photon energy above a threshold of about 5.5 eV (225 nm). The kinetics of these processes were, however, dependent on the dose actually absorbed by the layer and, in the case of Si‐O‐Si formation, additionally on the oxygen concentration. The release of ammonia and methane accompanied the conversion process. Quantum‐chemical calculations on methyl substituted cyclotetrasilazanes as model compounds substantiate the suggested reaction scheme. Layers <100 nm in thickness based on mixtures of poly(1,1‐dimethylsilazane‐co‐1‐methylsilazane) and perhydropolysilazane (PHPS) were coated onto polyethylene terephthalate (PET) foils by a continuous roll to roll process and cured by VUV irradiation by using wavelengths <200 nm and investigated for their O₂ and water vapor‐barrier properties. It was found that the resulting layers displayed oxygen and water vapor transmission rates (OTR and WVTR, respectively) of <1 cm³ m^?2 d^?1 bar^?1 and <4 g m^?2 d^?1, respectively.     

用于低温浆态床二甲醚水蒸气重整制氢的水解组分γ-Ga2O3的制备与表征

以有机溶剂均匀沉淀法制备了镓的氧化物,借助XRD、NH₃-TPD、TEM和BET等手段对物相结构、表面性质等进行了表征。结果表明,制备过程中得到的前驱体为GaOOH,前驱体经500 ℃热处理后得到γ-Ga₂O₃。γ-Ga₂O₃的晶格类型与γ-Al₂O₃相似,为有阳离子缺陷的立方尖晶石结构。表面具有酸量较大的中强酸中心,而弱酸中心含量相对较少。微观上大多为厚10 nm、直径100 nm左右的二维纳米片,大部分纳米片分布于一个方向,一些组成花瓣形。将制得的γ-Ga₂O₃用于DME水解反应,结果表明,270 ℃下DME的转化率可达24%,接近平衡转化率,反应后催化剂的织构性质没有显著变化,比表面积仍可达到130 m²/g。将γ-Ga₂O₃与Cu基催化剂复合后用于270 ℃下的低温浆态床DME水蒸气重整反应,DME转化率和H₂选择性高达99%和68%,经200 h反应后催化剂仍能保持95%以上的活性,表现出良好的工业化应用前景。     

无机阴离子、异丙醇及TiO_2对Fe~(3+)诱导全氟辛酸光化学降解影响的研究

254nm紫外光辐照下,溶解性Fe3+的存在有效促进了全氟辛酸(PFOA)的光化学降解.Fe3+浓度为30μmol·L-1时,Fe2(SO4)3,FeCl3和Fe(NO3)3三种溶解性铁盐对PFOA的降解和脱氟没有显著的差别.过量的SO24-与Fe3+具有较强的形成配合物的能力,由软件Visual MINTEQ2.52计算得出,Fe3+与过量的SO42-形成Fe(SO4)+和Fe(SO4)-2两种形态的配合物,其分配比的总和占16.32%,从而减少了PFOA与铁离子形成配合物的机会,进而抑制了其有效的光化学降解;过量的Cl-与Fe3+形成一配位的FeCl2+,其生成量仅占所有铁物种形态总和的0.12%,对PFOA的降解没有明显的影响,理论计算与实验结果相一致.羟基自由基捕获剂-异丙醇的加入未抑制PFOA的降解,二氧化钛的存在亦未促进其降解,进一步表明Fe3+诱导PFOA的光化学降解不是羟基自由基直接作用的结果.     

Vacuum Ultraviolet Excited Photoluminescence Properties of Y2O2S：Eu^3＋,Bi^3＋ Phosphor

As an Hg-free lamp using phosphor, the Bi^3＋ and EH^3＋ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet（VUV） excitation were investigated. The VUV photoluminescent intensity of Y2O2S：Eu^3＋ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S：Eu^3＋,Bi^3＋ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S：Eu^3＋,Bi^3＋ at 147 nm is mainly because the Bi^3＋ acts as a medium and effectively performs the energy transfer process： Y^3＋-O^2-→Bi^3＋→Eu^3＋, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ^1So-^1P1 transition of Bi^3＋ and the direct energy transfer from Bi^3＋ to Eu^3＋. The Y2O2S：Eu^3＋,Bi^3＋ shows excellent VUV optical properties compared with the commercial （Y,Gd）BO3：Eu^3＋. Thus, the Y2O2S：Eu^3＋,Bi^3＋ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.     

β-Ga2O3 nanowires sheathed with boron nitrogen

A new synthetic route was developed to obtain β-Ga₂O₃ nanowires by heating mixed B and Ga₂O₃ powder precursor at 1600 °C under Ar atmosphere. The nanowires have widths of 30–60 nm and perfect crystallinity. When the heating of B and Ga₂O₃ powder precursor was carried out in N₂ atmosphere, β-Ga₂O₃ nanowires sheathed with BN layers (3–5 nm) were yielded. The structure and composition of the products were characterized. The growth scenario for the β-Ga₂O₃ nanowires as well as the formation of outer BN sheaths was also discussed.     

组氨酸12-硅钨杂多酸盐超分子化合物的结构与光致变色性质

通过溶液法合成了一个新颖的组氨酸12-硅钨杂多酸盐((HisH₂)₂SiW₁₂O₄₀·6H₂O)单晶超分子化合物. 利用元素分析、热重-差热分析和X射线单晶衍射测试分别对其组成、热稳定性和结构进行了表征. 实验结果表明:该超分子化合物的组成为C₁₂H₃₄N₆O₅₀SiW₁₂. 空气中, 在135 °C以下稳定. 它属于单斜晶系(空间群为C2/c), 晶胞参数为a=2.44005(18) nm, b=1.29788(10) nm, c=1.86898(14) nm, β=124.0380(10)°, V=4.9048(6) nm³,Z=4 和D_c=4.465 g·cm^-3. 基于F²的最终统计: 拟合优度(GOF)=1.268, R₁=0.0344 和wR₂=0.0851 (I>2σ(I)). 该单晶超分子化合物的基本结构单元由一个[SiW₁₂O₄₀]^4-多阴离子和两个质子化的[H₂His]²⁺有机阳离子以及结晶水组成. 他们之间通过氢键的作用组装成三维网络结构. 在紫外光照射下, 样品具有光致变色性质. 通过对变色样品电子自旋共振谱的分析, 我们提出了一个可能的光致变色机理.