Manufacturing catalyst-coated membranes by ultrasonic spray deposition for PEMFC: Identification of key parameters and their impact on PEMFC performance

This study deals with the manufacturing of catalyst-coated membranes (CCMs) for newcomers in the field of coating. Although there are many studies on electrode ink composition for improving the performance of proton-exchange membrane fuel cells (PEMFCs), there are few papers dealing with electrode coating itself. Usually, it is a know-how that often remains secret and constitutes the added value of scientific teams or the business of industrialists. In this paper, we identify and clarify the role of key parameters to improve coating quality and also to correlate coating quality with fuel cell performance via polarization curves and electrochemical active surface area measurements. We found that the coating configurations can affect the performance of lab-made CCMs in PEMFCs. After the repeatability of the performance obtained by our coating method has been proved, we show that: (i) edge effects, due to mask shadowing - cannot be neglected when the active surface area is low, (ii) a heterogeneous thickness electrode produces performance lower than a homogeneous thickness electrode, and (iii) the origin and storage of platinum on carbon powders are a very important source of variability in the obtained results.     

Transition metal atoms anchored on nitrogen-doped α-arsenene as efficient electrocatalysts for nitrogen electroreduction reaction

Electrocatalytic reduction of N₂ to NH₃ under ambient conditions, inspired by biological nitrogen fixation, is a new approach to address the current energy shortage crisis. As a result, developing efficient and low-cost catalysts is critical. The catalytic activity, catalytic mechanism, and selectivity of α-arsenene (α-Ars) catalysts anchored with various transition metal atoms and doped with different numbers of N atom were investigated for N₂ reduction reaction (NRR) in this paper. Results reveal that compared with WN₃-α-Ars which is coordinated with three N atoms, asym-WN₂As-α-Ars that coordinated with two N atoms not only exhibits high catalytic activity (U_L = ?0.36 V), but can also successfully suppress the hydrogen evolution reaction (HER). It is manifested that reducing the number of coordination atoms can promote the selectivity of the transition metal (TM) loaded N-doped arsenene catalysts. Furthermore, activity origin analyses show both the charge on 1N–NH and φ form volcano-type relationship with the limiting potential. The active center of the catalyst, which acts as the charge transporter and has the moderate ability to retrieve charges, is the most efficient in NRR. Overall, this research creates high performance NRR catalysts by varying the number of coordinating N atoms, which provides a novel idea for the development of new NRR catalysts.     

稳产国Ⅵ柴油并兼产喷气燃料技术方案的工业应用

介绍了浙江石油化工有限公司新建的3 Mt/a柴油加氢精制装置，其配套使用中国石化石油化工科学研究院有限公司开发的催化剂级配技术，并实施了可根据原料供应及市场产品需求情况灵活调整切换的2种生产技术方案。1 a的安稳生产运行结果表明:该装置以直馏柴油为主原料，通过分馏塔的馏分切割及其侧线抽出，实现了稳产国Ⅵ柴油并兼产喷气燃料技术方案的工业化应用；在实施以兼产喷气燃料为主的生产技术方案时，通过调整常一线柴油的掺炼量，不仅可以生产含硫量小于10.0 μg/g的精制柴油产品，同时兼产所得到的喷气燃料产品含硫量小于0.5 μg/g，赛波特颜色号值大于30；在实施主产精制柴油组分方案时，通过掺炼质量分数为20%~40%的催化柴油，并使所提炼得到的精制柴油组分含硫量小于6.0 μg/g的前提下，这些精制柴油组分产品既可直接作为满足国Ⅵ柴油产品出厂待售，也可作为柴油调和组分储存待用于产品的进一步优化。     

焙烧态水铝钙石催化剂的制备及催化合成生物柴油

分别采用共沉淀法、清洁法制备焙烧态水铝钙石,通过低温N2吸脱附法、CO2-TPD、XRD、DTA和FT-IR表征结构,并将其作为大豆油与甲醇酯交换合成生物柴油的催化剂,探讨制备方法对焙烧态水铝钙石催化合成生物柴油的影响。此外,考察了Ca/Al摩尔比、焙烧温度、甲醇与大豆油摩尔比(醇油比)、催化剂用量和反应时间对酯交换合成生物柴油的影响。结果表明,清洁法制备的焙烧态水铝钙石具有更高的比表面积,强碱中心的表面碱量更大,催化活性更高。当Ca/Al摩尔比为2∶1,焙烧温度为600℃时,制备的Ca2Al O-2-600催化剂的催化活性最高,在醇油比8∶1、催化剂用量3%、反应温度65℃、反应时间4 h的条件下,大豆油转化率达到98. 0%。催化剂经重复使用3次后仍保持较高催化活性。     

费-托合成油加氢脱氧催化剂研究

费-托合成油中存在少量的含氧化合物，会影响烯烃聚合制备聚α-烯烃（PAO）的收率和产物选择性。将费-托合成油中的含氧化合物（主要为醛、酮类）选择性加氢生成相应的醇，然后通过醇与金属钠反应生成醇钠，再通过蒸馏脱除醇钠，达到脱除含氧化合物的目的。分别将Cu，Cu-Zn，Cu-K，Cu-Ni，Pt负载在α-Al2O3和γ-Al2O3上制备催化剂，考察催化剂对费-托合成模拟油的加氢脱氧反应性能，并对催化剂进行表征。结果表明：费-托合成油中主要组分为烯烃和烷烃，少量含氧化合物主要为酮和醛；通过加氢可以将费-托合成油中的含氧化合物转化为醇，但对烯烃有饱和作用，以α-Al2O3为载体的催化剂的选择性优于以γ-Al2O3为载体的催化剂；Cu-Zn/α-Al2O3催化剂效果最好，在温度为180 ℃、压力为1 MPa、体积空速为2 h-1、氢油体积比为50的条件下进行模拟油的加氢试验，烯烃损失12%，醛加氢转化率达到95.3%，没有发现醇加氢生成烃类的反应发生。     

FCC废催化剂镁改性催化裂化性能再生研究

提出并证实了高的强酸性位可接近性导致FCC废催化剂失活的机制。基于所提出的失活机制，采用浸渍法对FCC废催化剂进行镁改性再生。对所制备的再生FCC废催化剂进行了表征并考察了其重油催化裂化性能。表征结果表明，与未改性的FCC废催化剂相比，再生FCC废催化剂表面酸强度被一定程度地削弱，而表面总酸量和结构性质参数未出现显著改变。重油催化裂化结果表明，得益于适宜的表面酸性，再生FCC废催化剂的催化裂化反应性能得到极大改善。与未改性的FCC废催化剂相比，再生FCC废催化剂的汽油产率显著增加了3.04个百分点，同时干气、液化气、焦炭和重油产率则分别下降了0.36、0.81、1.28和0.87个百分点，这使得所制备的再生FCC废催化剂可以代替部分新鲜FCC催化剂使用。最后，探讨了再生FCC废催化剂表面酸性改变机理。     

Electrochemical synthesis of Li-doped NiFeCo oxides for efficient catalysis of the oxygen evolution reaction in an alkaline environment

Oxygen evolution reaction (OER) is an essential reaction for overall electrochemical water splitting. In this present study, we adopt a facile electrochemical deposition method to synthesize the Li-doped NiFeCo oxides for OER in an alkaline medium. The scanning electron microscopy, X-ray diffraction, Brunauer-Emmet-Teller method and X-ray photo-electron spectroscopy provides the information of morphology, structure, specific surface area and electronic state of the electrocatalysts respectively. Investigates the electrochemical properties by the thin-film technique on a rotating disk electrode and in a single-cell laboratory water electrolyzer connects with electrochemical impedance spectroscopy. Among the catalysts under investigation, Ni_0·9Fe_0·1Co_1·975Li_0·025O₄ exhibits the highest activity towards oxygen evolution reaction, and explains the activity by the oxygen binding energy; such knowledge can be helped to develop better catalyst. We achieve onset over potential 220 mV and receive 10 mA cm^?2 current density at over potential 301 mV with Tafel slope 62 mV dec^?1 in 1 M KOH solution. The results are similar to recently published catalysts in the literature. In water electrolyzer, the Ni_0·9Fe_0·1Co_1·975Li_0·025O₄ modified nickel foam anode exhibits a current density of 143 mA cm^?2 at a cell voltage of 1.85 V in 10 wt% KOH and a temperature of 50 °C.     

Factors influencing CH4CO2 reforming reaction over Fe catalyst supported on foam ceramics under microwave irradiation

In this work, a CH₄CO₂ reforming reaction was carried out under microwave irradiation using Fe/(SiC·SiO₂) and Fe/(Al₂O₃·SiC) catalysts. The temperature-change behavior of the catalysts and the effects of microwave power, catalyst carriers, active component content, and space velocity on the dry reforming reaction were investigated. The Fe/(SiC·SiO₂) catalyst reached the steady temperature quickly, while the heating process of Fe/(Al₂O₃·SiC) involves three stages with a small heating rate and it took longer to reach the steady temperature. The performance of Fe/(SiC·SiO₂) was obviously better than that of Fe/(Al₂O₃·SiC). And it was observed that about 95% conversions of reactants were achieved with Fe content of 12 wt%, space velocity of 200 h^?1, and microwave power of 90 W/g. Thus, Fe-based catalysts supported on foam ceramics exhibit good performance in the microwave CH₄CO₂ reforming reaction.     

The influence of transition metals – Fe,Co, Cu on transformation of organic matters from Domanic rocks in hydrothermal catalytic system

Character of conversion of organic matter from Domanic rocks of Pervomaiskoye field (Tatarstan) of Semiluki horizon of upper Devonian deposits in the hydrothermal-catalytic system at temperature of 300?°C in carbon dioxide medium was studied with the application of complex of oil-soluble precursors of catalysts containing Fe, Co, and Cu. In presence of catalysts complex, content of organic extract increases, in which content of hydrocarbon fractions, saturated and aromatic hydrocarbons, increases 1.5 times, while resins content decreases by two times. As result of kerogen destruction in products of experiments, the content of asphaltenes and carbonaceous substances such as carbenes and carboides increase.