生物质活性炭的制备及其在阳极中的性能

以竹子为原料制备生物质活性炭,使用HNO3溶液浸渍实现活性炭表面改性和降低灰分,在流化床电极直接碳燃料电池阳极半电池中考察活性炭的极化性能。结果表明:活化温度为1173K、活化时间为2h、碱炭比为1时,活性炭比表面积为1264m2/g,电阻率为1569μΩ.m;HNO3溶液浸渍后,活性炭表面含氧官能团的种类和含量明显增加,灰分也有较大程度降低,最佳HNO3浸渍浓度为2mol/L;自制活性炭在半电池中的极化性能明显优于石墨和活性炭纤维。     

可见光响应负载型Er3+∶YAlO3/TiO2-SAC光催化剂的制备及其性能研究

为使TiO2能在可见光下发挥其于紫外激发的高光催化活性,且易于从处理废水中分离,采用溶胶-凝胶法将TiO2与掺杂稀土离子Er3+的上转换发光剂Er3+∶YAlO3结合再负载到球形活性炭(SAC)表面,制备可见光响应的负载型Er3+∶YAlO3/TiO2-SAC光催化剂并对其进行表征。以甲基橙为目标污染物,研究了制备的催化剂在可见光下催化活性,并探讨不同Er3+∶YAlO3/TiO2的负载方式、负载量等制备条件对光催化剂活性的影响。结果表明,结合方式为Er3+∶YAlO3/TiO2烧结后与SAC在乙醇介质中混合并进行30min磁力搅拌、以Er3+∶YAlO3/TiO2与SAC质量比为1∶4时制备的光催化剂活性最高,甲基橙的脱色率在240min可达97%以上。     

纳米TiO2光催化剂负载和光催化反应器的研究进展

纳米TiO2光催化氧化技术在废水处理领域具有广阔的应用前景。将纳米Ti02负载到某种载体上,并设计出高效的光催化反应器是实现光催化氧化技术处理废水实用化的关键技术之一。本文对纳米TiO2光催化剂负载所用的载体、负载型光催化剂的制备方法及其光催化反应器进行了综述。     

红磷-TiO_2复合光催化剂的制备及其光催化产氢性能

采用机械混合法制备了红磷-Ti O_2(P-Ti O_2)复合光催化剂,并对催化剂进行了X射线衍射、紫外-可见光漫反射、透射电子显微镜表征。以甲醇为牺牲试剂,铂为助催化剂,在可见光辐照下对P-Ti O_2复合光催化剂进行了光催化分解水产氢性能测试,并提出了红磷和Ti O_2可能的作用机理。研究结果表明:红磷和Ti O_2复合后,光催化剂的产氢性能显著提高,当P-Ti O_2中Ti O_2的质量分数为5%时,光催化剂的产氢性能最高,产氢速率可达到52.6μmol/(h·g),为纯红磷样品的2.54倍;红磷和Ti O_2复合后在其接触面上形成了p-n结,并通过p-n结实现了光生电子从红磷到Ti O_2的传递,从而与Pt发生还原反应产生氢气。     

高级氧化技术中分子筛负载纳米TiO2的光催化性能的研究

选择溶胶-凝胶方法制作纳米TiO₂,且将纳米TiO₂负载于分子筛上面。实验结果表明,与非负载光催化剂相比,负载光催化剂具体性能更优。针对目标物实行降解时,最优条件为,pH值是4.7,H₂O₂最初的物质的量浓度是25 mmol/L,甲基橙最初的质量浓度是20 mg/L,增加量是2 g;温度升高有利于降解;随应用频次提升,催化剂具体活性渐渐下降。     

基于正交试验制备废弃原棉活性炭及其吸附亚甲基蓝的研究

以废弃原棉(简称"原棉")为原料,采用FeCl_3/ZnCl_2混合物为活化剂制备活性炭,以活性炭得率和碘吸附值为试验指标,采用正交法考察了活化剂质量比、活化温度以及活化时间的影响,从而得到最优工艺参数:FeCl_3/ZnCl_2质量比为1∶1、活化温度为400℃以及活化时间为1 h。将最优样(AC-Fe/Zn)应用于吸附阳离子有机染料亚甲基蓝实验,结果表明:吸附过程符合Langmuir吸附等温模型,最大吸附量为342.87 mg·g~(-1)。     

生物质活性炭对亚甲基蓝的吸附平衡和动力学研究

利用玉米芯为原料制备的活性炭吸附水相中不同浓度的亚甲基蓝溶液,亚甲基蓝的初始浓度为50～250mg/L。试验条件:吸附时间为1～48h、亚甲基蓝的初始浓度为50～250mg/L、温度为30℃,得到了玉米芯活性炭吸附亚甲基蓝的吸附等温线和吸附动力学曲线。试验结果表明:Freun-dlich吸附等温线模型能够比较准确地描述亚甲基蓝在玉米芯活性炭上的吸附相平衡;准二级反应模型更准确地描述玉米芯活性炭的吸附过程;平衡时活性炭的吸附能力为48.5～225mg/g。由此可知,玉米芯活性炭对去除水溶液中的亚甲基蓝染料效果佳,是一种具有发展潜力的吸附剂。     

直接碳燃料电池活性炭制备的实验研究

以KOH为活化剂,采用化学活化法对橡木锯屑制取活性炭进行了实验研究。考察了活化温度、碱炭比和活化时间对活性炭比表面积的影响,得到了制取活性炭的最优工况,随后对此工况下的活性炭先后使用HNO3浸渍和乙酸镍Ni负载。结果表明,最优工况下制备的活性炭比表面积为1967m2/g。HNO3浸渍可以增加活性炭表面含氧官能团的种类和含量,也能较大程度地降低活性炭的灰分,乙酸镍Ni负载后,活性炭体积电阻率降低了很多。     

浸渍提拉法制备TiO_2薄膜及其光催化性能的研究

以钛酸四异丙酯为原料配制成胶体 ,在玻璃管表面制备了 Ti O2 薄膜光催化剂。用该催化剂光催化降解四氯乙烯 ,并进行薄膜厚度与光解率关系以及催化剂寿命实验。结果表明 ,其光催化效率接近 Ti O2 粉末悬浮体系 ,薄膜以厚度 60 0— 80 0 nm为宜 ,使用 10 0 h,Ti O2 薄膜的光催化活性没有减弱 ,可连续使用     

甘肃省低阶煤基活性炭的制备及性能研究

活性炭是一种经特殊处理的炭。煤基活性炭是一种以煤炭为原料,经过磨粉、成型、炭化、活化等工序制成的活性炭。以甘肃省中部地区窑街煤电金河煤炭为原料,在对原料煤进行工业分析、元素分析、二氧化碳反应活性测定的基础上,利用水蒸气活化法,通过单因素试验和正交试验设计,制备得到金河煤基活性炭,考察了活化时间、活化温度、水蒸气流量等因素对活性炭性能的影响。研究结果发现当活化温度为900℃,活化时间4h,水蒸气流量0.20mL/min时,金河煤基活性炭的最高碘吸附值为588mg/g,经酸法脱灰后,其吸附值增加至716mg/g。同时,将脱灰后的活性炭对初始浓度400mg/L苯酚废水进行处理,当投炭量0.10g、初始溶液pH值为7时,去除率可达79%。通过性能表征和吸附试验,验证了制备所得煤基活性炭具有良好的介孔结构和吸附性能。     

松子壳热解炭活化特性研究

以松子壳为原料,采用常规热解法得到松子壳炭,利用水蒸气活化的方法制备了微孔率较高的活性炭,并测定其吸附能力。利用红外光谱(FT-IR)、氮气吸脱附曲线、扫描电镜(SEM)对热解炭及相应活性炭进行了表征。最佳活化工艺为活化温度850℃,活化时间60 min,水蒸气流量0.3 g/min。在该条件下松子壳活性炭得率为34%,亚甲基蓝吸附值为186 mg/g,碘吸附值为1 097 mg/g,比表面积为1 094.895 m2/g,平均孔径为3.95nm。微观结构分析表明,热解炭已经具备一定的孔隙结构,活化过程中活化剂能够有效去除堵塞热解炭孔隙的杂质和不定型炭,形成丰富的微孔结构和少量的介孔、大孔。该研究为松子壳活性炭的制备提供了理论依据。     

Preparation and characterization of activated carbon from pistachio nut shells via microwave-induced chemical activation

In this work, pistachio nut shell, a biomass residue abundantly available from the pistachio nut processing industries, was utilized as a feedstock for the preparation of activated carbon (PSAC) via microwave assisted KOH activation. The activation step was performed at the microwave input power of 600 W and irradiation time of 7 min. The porosity, functional and surface chemistry were featured by means of low temperature nitrogen adsorption, scanning electron microscopy and Fourier transform infrared spectroscopy. Result showed that the BET surface area, Langmuir surface area, and total pore volume of PSAC were 700.53 m² g⁻¹, 1038.78 m² g⁻¹ and 0.375 m³ g⁻¹, respectively. The adsorptive property of PSAC was tested using methylene blue dye as the targeted adsorbate. Equilibrium data was best fitted by the Langmuir isotherm model, showing a monolayer adsorption capacity of 296.57 mg g⁻¹. The study revealed the potentiality of microwave-induced activation as a viable activation method.     

Preparation of activated biomass carbon from pine sawdust for supercapacitor and CO2 capture

Biomass based carbon has captured more and more attention because it is environmentally friendly and has properties of low cost and ideal sustainability. In this study, three kinds of activated biomass carbons (ie, ABC-700, ABC-800 and ABC-900) were first carbonized through pine sawdust pyrolysis and then activated using KOH under three different activation temperatures (ie, 700°C, 800°C and 900°C). The structure properties of the prepared activated biomass carbons were characterized by N₂-adsorption/desorption, SEM, TEM, XRD, Raman, XPS, TG and ultimate analysis. To clarify the activation mechanism, the gas products produced during KOH activation process were measured online with an ETG gas analyzer. The performance of the activated biomass carbons derived from pine sawdust for supercapacitor and CO₂ capture was then evaluated. The predominant gas products during the activation process are H₂ and CO. It indicates that the porous structure was created by using an enhanced etching reaction between carbon atoms and KOH. An increment of the activation temperature from 700 to 900°C results in the increase of surface area (from 1728.66 to 2330.89 m²/g) and total pore volume (from 0.671 to 1.914 cm³/g). Among the three samples, ABC-900 exhibits the maximal specific capacitance of 175.6 F·g⁻¹ and high energy density of 24.39 Wh·kg⁻¹ at the 0.5 A·g⁻¹. And the ABC-700 shows the maximal CO₂ capture capacity of 4.21 mmol/g and high selectivity of CO₂ over N₂ at 298 K and 1 bar. In addition, ABC-700 also has excellent stability and reproducibility after 15 times adsorption-desorption cycles. The unexceptionable electrochemical performance and adsorption capacity of the biomass-carbons show its broad application prospects in the field of supercapacitors and CO₂ capture.     

Preparation,characterization and electronic properties of LaFeO3 perovskite as photocatalyst for hydrogen production

Perovskite-type LaFeO₃ was successfully used as photocatalyst for the H₂ production. It was prepared by a conventional sol-gel technique via the nitrate route. X-Ray fluorescence/Energy Dispersive X-Ray fluorescence (XRF), X-Ray Diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), UV–Visible diffuse reflectance, FTIR spectroscopy, Scanning Electron Microscopy (SEM/EDX) and specific surface area were deployed to characterize the synthetized material after heat-treated at 850 °C. LaFeO₃ crystallizes in a cubic structure (Space Group: Pm3 m) with a crystallite size of 16 nm and BET surface area of 12 m²/g. Field-dependent magnetization was measured at 300 K in the region (±25 kOe) and the perovskite exhibits a high magnetism with a saturation magnetization (0.15 emu/g). Such result indicates that the Fe-3d are in localized high spin state. LaFeO₃ has a narrow band gap of 2.08 eV determined by diffuse reflectance resulting to the crystal field splitting of 3d orbital of Fe³⁺ octahedrally coordinated with an internal d-d transition. Cyclic voltammetry showed the reduction of adsorbed H₂O molecules to gaseous hydrogen at −0.7 V_SCE, a potential less cathodic than the conduction band (−0.45 V_SCE). The latter was determined from the capacitance measurements in alkaline electrolyte (NaOH 0.1 M) where the perovskite exhibits a stability with an exchange current density of ∼0.4 mA cm⁻². The photocatalytic activity reveals an optimal H₂ production of 99 μmol after 20 min at 50 °C in NaOH medium and a catalyst mass of 50 mg, under visible light irradiation (13 W) in the presence of thiosulfate S₂O₃²⁻ as hole scavenger.     

Deactivation of palm shell-based activated carbon catalyst used for hydrogen production by thermocatalytic decomposition of methane

Thermocatalytic decomposition of methane over activated carbon acting as a catalyst is proposed as a potential alternative for hydrogen production. However, over a certain duration catalyst becomes deactivated due to intensive carbon deposition.     

微生物燃料电池MnO_2及活性炭混合催化剂的制备及其性能研究

利用机械混合及化学复合两种混合方式制备出用于微生物燃料电池(MFC)阴极的Mn O_2与活性炭导电材料的混合催化剂,混合质量比分别为1∶3,1∶1和3∶1。将以各催化剂制作的碳布阴极置于空气阴极MFC中运行,利用线性扫描伏安法测试碳布阴极的性能。研究表明,两种混合催化剂均在混合质量比为1∶1时具有最佳性能;化学复合催化剂MFC的最大功率密度达到336 m W/m~2,是单纯使用Mn O_2粉末时的2.51倍,优于机械混合的催化剂。     

The catalytic performance enhancement of Ni2P electrocatalysts for hydrogen evolution reaction by carbon-based substrates

Combination of catalytic active components with substrates is deemed to be a promising approach to pursue high active and stable catalysts. Wherein, carbon-based materials as a kind of frequently-used substrates are well developed, and thus the different effects of them on catalytic active components deserve investigating and contrasting. In this work, well dispersive and ultrafine Ni₂P nanoparticles supported on N-doped reduced graphene oxide (N-RGO) were synthesized through a facial hydrothermal process and subsequent phosphorization. The prepared Ni₂P/N-RGO demonstrates a superior electrocatalytic activity towards hydrogen evolution reaction (HER) in 0.5 M H₂SO₄ solution with a low onset overpotential (80 mV) and small Tafel slope (93.1 mV dec⁻¹). Additionally, as compared with other representative carbon materials (carbon black (C) and carbon nanotubes (CNTs)) in the perspective of specific surface area (SSA), conductivity and electronic interaction in particular, N-RGO demonstrates a preeminent promotional effect as a substrate of Ni₂P.     

The fuel properties of pyrolytic oils obtained from catalytic pyrolysis of non-recyclable pulper rejects using activated natural minerals

In this study, catalytic pyrolysis of pulper rejects was performed with catalysts obtained from activated clinoptilolite and meerschaum for the production of pyrolytic fuel oils. The increasing proportion of polymers in rejects led to an increase in oil yield in non-catalytic process. The highest liquid (61.4%) and char (32.19%) yields were obtained using 15% clinoptilolite and 5% meerschaum, while the highest gas yield (21.44%) was obtained via the non-catalytic process. The fuel properties of the oils were significantly enhanced with the catalytic process. The clinoptilolite catalyst showed better performance compared to the meerschaum in terms of oil yield and fuel properties.     

Preparation,structure and application of g-C3N4/BiOX composite photocatalyst

Graphite-like carbon nitride (g-C₃N₄) has attracted great attention for pollutant degradation and clean energy production. The heterojunctions of bismuth halide (BiOX, X = Cl, Br, I) and g-C₃N₄ are proposed to overcome the shortcomings of the g-C₃N₄ photocatalyst, such as low charge separation rate and high charge recombination rate. This review paper systematically discusses the progress in synthesis, structure, and applications of heterojunction photocatalytic composites made of g-C₃N₄ and BiOX based on the understanding of their photocatalytic reaction mechanism. We clarify and summarize structural mechanisms of a single and compound semiconductor to reveal the factors that affect photocatalytic performances. We discuss and compare advantages and disadvantages of versatile preparation processes. Particularly, we focus on the understanding of the structure and characteristics of type II, Z-type, n-n, and p-n heterojunctions and their applications, specifically in pollutant degradation, H₂ production by water splitting, CO₂ reduction, and medical sterilization. The future prospects of g-C₃N₄/BiOX composites are also discussed from aspects of their preparation, application, and research methods. This work may offer a good avenue and data reference to develop novel g-C₃N₄ photocatalytic materials to meet the ever-increasing environmental pollution and energy shortage.     

Preparation of activated carbon supported Pt catalysts and optimization of their catalytic activities for hydrogen gas production from the hydrothermal treatment of biomass-derived compounds

In the fields of energy science, it is a challenging issue to develop a highly active catalyst for hydrogen-rich gas production from biomass-derived compounds. In the present study, active reforming catalysts for use of gasification of glucose, biomass-derived compound, in aqueous medium were developed by deposition of platinum on active carbon (AC) support using nanotechnological approaches in supercritical carbon dioxide (ScCO₂) media and impregnation (IMP) in aqueous media. Effects of reduction methods for platinum metal and chemical treatment for AC support were evaluated for hydrogen production activity.