NaBH4水解制氢技术

介绍了一种方便、实用且能有效制备高纯度氢气的新型制氢技术———NaBH4水解制备氢气。NaBH4(水溶液)与催化剂作用,水解产生氢气和一种水溶性盐———NaBO2。该反应中,氢的生成速度容易控制;制得的氢气纯度高,不需要纯化过程,可直接作为燃料电池的原料;催化剂可以循环使用;甚至在0℃下也可以生产氢气,无污染。另外,还介绍了本文发明的催化剂和相应的反应器体系,具有催化剂便宜,反应器安全、易于控制等特点。     

硼氢化钠水解制氢研究进展

硼氢化钠水解制氢作为一种安全、方便的新型制氢技术成为当前燃料电池氢源研究中的热点课题之一.本文介绍了硼氢化钠制氢原理,综述了硼氢化钠水解催化剂和反应动力学研究进展,并对硼氢化钠制氢技术实用化前景进行了展望.     

Hydrogen Production by Catalytic Hydrolysis of Sodium Borohydride with a Bimetallic Solid-State Co-Fe Complex Catalyst

The addition of the active non-noble metal species on a ligand can influence the catalytic performance of catalyst. In the present work, a new bi-metallic solid-state complex catalyst system, including 4-4’-methylene bis(2,6-diethyl) aniline-3,5-di-tert-butylsalisilaldimin ligand and Fe and Co metal salts are prepared for hydrogen generation by catalytic hydrolysis of NaBH₄. It was found that the Co/Fe mixture ratio, temperature, NaBH₄, and NaOH concentrations, all exert considerable influence on the catalytic effectiveness of Co–Fe complex catalyst towards the hydrolysis reaction of NaBH₄. The results suggested that the optimal mixture percentage of Co–Fe complex catalyst is 80:20. The obtained complex catalysts are characterized by XRD, FT-IR, and SEM techniques.     

非晶态Ni-W-B合金的制备及催化硼氢化钠水解制氢

采用化学还原法合成了非晶态金属硼化物Ni-W-B合金,并用于硼氢化物水解制氢。通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)、X射线能谱分析(EDX)证明,样品Ni-W-B为非晶态的、均匀的球形颗粒,平均粒径约60~70 nm。催化活性实验证明,Ni-W-B合金对Na BH4水解制氢有较好的催化活性;W的含量对催化活性有一定影响,其W与Ni的最佳摩尔比为0.1。影响因素实验证明,Na BH4水解制氢速率与体系温度及催化剂用量呈正比。使用寿命测试证明,经过10次水解循环之后催化剂活性没有明显降低,说明Ni-W-B催化剂有较好的稳定性。     

Sodium Borohydride Hydrolysis as Hydrogen Generator: Issues,State of the Art and Applicability Upstream from a Fuel Cell

Today there is a consensus regarding the potential of NaBH₄ as a good candidate for hydrogen storage and release via hydrolysis reaction, especially for mobile, portable and niche applications. However as gone through in the present paper two main issues, which are the most investigated throughout the open literature, still avoid NaBH₄ to be competitive. The first one is water handling. The second one is the catalytic material used to accelerate the hydrolysis reaction. Both issues are objects of great attentions as it can be noticed throughout the open literature. This review presents and discusses the various strategies which were considered until now by many studies to manage water and to improve catalysts performances (reactivity and durability). Published studies show real improvements and much more efforts might lead to significant overhangs. Nevertheless, the results show that we are still far from envisaging short‐term commercialisation.     

硼氢化钾水解制氢双金属催化剂研究

实验制备了活性炭(AC)负载钴-镍基双金属催化剂,利用XRD对其进行表征。实验研究了不同催化剂、反应温度和硼氢化钾浓度等因素对制氢反应的影响。研究结果显示,10%(wt)Co-Ni/AC催化剂中,金属钴的比例越大,催化剂的活性越好。反应温度对反应速率有很大影响。硼氢化钾浓度对产氢率有一定影响。     

硼氢化物催化水解制氢作为燃料电池氢源(英文)

Borohydrides present interesting options for the electrochemical power generation acting either as hydrogen source or anodic fuel for direct borohydride fuel cells(DBFC).In this work,Mg-Ni composite synthesized by mechanically alloying method,used as the catalyst for the hydrolysis of borohydride,has been investigated.Co-doping treatment has been carried out for the purpose of improving the hydrolysis rate further.The as-prepared and Co-doped Mg-Ni composites with low cost showed high catalytic activity to the hydrolysis of borohydride for hydrogen generation.After Co-doping,the hydrogen generation rate was around 280 ml·g-1·min-1.Borohydride would be a promising hydrogen source for fuel cells.     

Hydrogen Production from Ethanol Steam Reforming Over Supported Cobalt Catalysts

Hydrogen production was carried out via ethanol steam reforming over supported cobalt catalysts. Wet incipient impregnation method was used to support cobalt on ZrO₂, CeO₂ and CeZrO₄ followed by pre-reduction with H₂ up to 677 °C to attain supported cobalt catalysts. It was found that the non-noble metal based 10 wt.% Co/CeZrO₄ is an efficient catalyst to achieve ethanol conversion of 100% and hydrogen yield of 82% (4.9 mol H₂/mol ethanol) at 450 °C, which is superior to 0.5 wt.% Rh/Al₂O₃. The pre-reduction process is required to activate supported cobalt catalysts for high H₂ yield of ethanol steam reforming. In addition, support effect is found significant for cobalt during ethanol steam reforming. 10% Co/CeO₂ gave high H₂ selectivity while suffered low conversion due to the poor thermal stability. In contrast to CeO₂, 10 wt.% Co/ZrO₂ achieved high conversion while suffered lower H₂ yield due to the production of methane. The synergistic effect of ZrO₂ and CeO₂ to promote high ethanol conversion while suppress methanation was observed when CeZrO₄ was used as a support for cobalt. This synergistic effect of CeZrO₄ support leads to a high hydrogen yield at low temperature for 10 wt.% Co/CeZrO₄ catalyst. Under the high weight hourly space velocity (WHSV) of ethanol (2.5 h⁻¹), the hydrogen yield over 10 wt.% Co/CeZrO₄ was found to gradually decrease to 70% of its initial value in 6 h possibly due to the coke formation on the catalyst.     

Combined Usage of Sodium Borohydride and Aluminum Powder for High‐performance Hydrogen Generation

The sodium borohydride (NaBH₄)‐based hydrolysis system has received considerable interest as a potential hydrogen source for vehicular application. But its practical application was greatly restricted by the low hydrogen density and high material cost. In the present study, we reported that addition of aluminum (Al) powder is an easy but highly effective way for addressing the problems of the NaBH₄‐based hydrolysis system. The system was composed of alkaline aqueous solution of NaBH₄ and solid powder mixture of Al and Co₂B catalyst. The effects of alkaline concentration, NaBH₄ concentration and Al amount on the hydrogen generation (HG) performance of the system were investigated. Our study showed that there exist a mutual‐promoting mechanism between the hydrolysis reaction of NaBH₄ and the Al/H₂O reaction. As a consequence, this system exhibited distinct advantages over the conventional NaBH₄‐based system in terms of HG rate, fuel conversion, hydrogen density and H₂ production cost. These favourable attributes make the (NaBH₄+Al)/H₂O system attractive for mobile/portable hydrogen source applications.     

硼氢化钠合成新工艺研究

偏硼酸钠是硼氢化钠的还原副产物。以偏硼酸钠为原料,与金属钠、石英砂进行加氢反应来制备硼氢化钠。用异丙胺对产物进行萃取提纯,制得了纯度较高、收率为47·8%的硼氢化钠产品。萃取剂回收利用率可达85%。     

KCC-1 Supported CuCo Bimetal Catalysts for Promoting Hydrogen Production from Ammonia Borane Hydrolysis

Catalysis Letters - Dendritic fibrous KCC-1 supported CuCo bimetal catalysts (CuCo/KCC-1) are fabricated by coprecipitating Cu2+ and Co2+ on the surface of KCC-1 nanospheres. The microstructure and...     

非贵金属Ni2P助催化剂修饰KCa2Nb3O10超薄纳米片的光解水产氢性能研究

开发高效非贵金属助催化剂是光解水产氢领域研究的重点.首次将Ni2P纳米颗粒作为高效助催化剂经一步热处理法修饰在KCa2Nb3O10超薄纳米片表面,成功构建了Ni2P/KCa2Nb3O10复合光催化剂,所制备的复合光催化剂展现出具有丰富异质界面的二维纳米结构,活性最佳的Ni2P/KCa2Nb3O10产物光催化产氢效率高达72.25μmol g-1 h-1,是纯相KCa2Nb3O10产氢效率的18.8倍.提供了一种负载其他非贵金属助催化剂制备高效KCa2Nb3O10基复合光催化剂的新策略.     

Investigation of Ni Foam Effect for Direct Borohydride Fuel Cell

Ni foam has been used as a substrate for the anode electrocatalyst in our previous works. In this study, the effect of nickel foam as an anode electrode in direct borohydride cells has been investigated under steady state/steady‐flow and uniform state/uniform‐flow systems, since nickel has catalytic property. Cathode catalyst used has been 0.3 mg cm^–2 on PTFE‐treated Toray carbon paper. The results have showed that power densities have increased by increasing the temperature. Peak power densities of 5.01 and 9.55 mW cm^–2 have been achieved at 25 and 60 °C, respectively, for 1.5 mol dm^–3 NaBH₄. On the other hand, the electrochemical performance has not been significantly different by the sodium borohydride concentration; only a small increase of power density has been observed in steady state/steady‐flow system, and only a small decrease of fuel utilization ratio has been obtained in uniform state/uniform‐flow systems.     

Copper Removal from Water by Chemical Reduction with Sodium Borohydride

Abstract

The use of NaBH₄ as a chemical reductant to precipitate copper from water has been studied. Initial Cu²⁺ concentrations of 25 and 40 mg/L have been checked, and complete removal can be achieved. When solid NaBH₄ is fed, BH₄ ^? to Cu²⁺ molar ratios higher than 2 were needed. This can be substantially improved by using NaBH₄ as a stabilized alkaline solution. A kinetic model is proposed which gives information about the relative rates of the two competitive reactions involved (Cu²⁺ and water reduction with BH₄ ⁰) and allows the operating conditions leading to minimum BH₄ ^? consumption to be established.     

福美钠钴渣回收钴的实验研究

采用"低酸酸洗-两段焙烧-溶剂萃取"工艺对福美钠钴渣回收工艺进行了研究,考察了氧化焙烧温度、焙烧时间、硫酸化焙烧温度、硫酸加入量等因素对钴浸出率的影响。结果表明:氧化焙烧最佳温度500℃,焙烧时间为0. 5～1 h,硫酸化焙烧温度400℃,硫酸加入量为干焙砂60%～70%(质量比),焙烧时间0. 5 h,钴浸出率可达99%。     

pH值对光合细菌利用乙酸(钠)产氢的影响

详细考察了pH值对光合细菌利用乙酸(钠)产氢的影响作用.研究结果表明,光合细菌利用乙酸(钠)产氢的最佳pH值为6.80;在最佳pH值下,乙酸(钠)的降解率为99.3%,氢气的转化率为0.91 mol H2/mol 乙酸,最大比产氢速度为34.6 mL/(g-VSS·d),能量转化率为22.8%.     

灰融聚流化床粉煤气化制氢技术方案设计

介绍灰融聚流化床粉煤气化技术特点、工艺流程、制氢能力以及后续配套工艺;提出采用多种干法除尘方案,使煤气含尘小于10mg/m3,再利用煤气中的水蒸气进行CO变换,从而简化制氢工艺。     

CDots-(001)TiO2纳米片的制备及其光解水制氢性能

以钛酸四丁酯、氢氟酸和石墨棒为原料,采用简单的水热法将具有高催化活性的碳点负载在TiO_2纳米片的(001)晶面上,制得CDots-(001)TiO_2纳米片。通过TiO_2纳米片高催化活性的(001)晶面与碳点的协同作用,提高TiO 2纳米片的光吸收、载流子的传输和分离效率,从而有效提高材料的光催化产氢性能。紫外-可见漫反射吸收谱(UV-visDRS)、光致发光光谱(PL)、瞬态光响应分析结果表明,暴露(001)晶面的TiO_2纳米片负载碳点后,可见光吸收增强,光生载流子的分离和传输速率加快,在间歇模拟太阳光照射下,CDots-(001)TiO 2纳米片的光电流密度约为TiO 2的4倍,当碳点的负载量为2%时,CDots-(001)TiO 2纳米片的光催化产氢速率达5859μmol/(h·g),量子效率达9.6%。     

钠盐浓度对厌氧产氢颗粒污泥从蔗糖中产氢的影响

This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na ), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L-1(Na )] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L-1·h-1, 28.04-28.97ml·g-1, 7.52-7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased, with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.     

铬酸钡与硫酸氢钠制备重铬酸钠的宏观反应动力学

考察了BaCrO4与NaHSO4制备Na2Cr2O7过程中搅拌速率、氢离子初始浓度、反应温度对BaCrO4转化率的影响,在机理分析基础上进行了宏观动力学研究. 结果表明,该过程为BaCrO4溶于酸性水溶液生成BaCr2O7、BaCr2O7与NaHSO4反应生成BaSO4与Na2Cr2O7、BaSO4结晶析出三步,反应过程中应尽量升高反应温度,搅拌速率可固定为400 r/min,而氢离子浓度应大于0.01 mol/L且小于NaHSO4饱和时的浓度. 经过对实验数据处理和分析,建立了宏观动力学模型,得出该反应为一级反应,求得活化能为41.029 kJ/mol,频率因子为15978.51,相应的宏观动力学方程为-ln(1-XA)=15978.51exp[-41.029′103/(RT)]t.