双电层电容器用酚醛树脂基活性炭的制备

以酚醛树脂为原料,KOH为活化剂制备双电层电容器用高比表面积活性炭电极材料。考察了工艺因素对活性炭比电容的影响,探讨了酚醛树脂基高比表面积活性炭作双电层电容器电极的电化学特性。结果表明,在固化温度为150℃、炭化温度为700℃,ζ(碱/炭)为4,活化温度为800℃时,制得的高比表面积活性炭双电极比电容可达74.2 F/g。     

KOH溶液处理对AlGaN紫外探测器暗电流的影响

采用KOH溶液表面处理工艺制备得到了128×1线列日盲AlGaN紫外探测器,器件的反偏暗电流为6.88×10-9A(-8 V时),比未采用此项工艺制备得到的器件的暗电流减小近103倍。元素深度分布俄歇电子谱(AES)等测试结果分析表明,采用这种表面处理工艺可以有效地去除干法刻蚀后材料表面的N空位、刻蚀生成物及自然氧化物,减小了界面态密度,改善了电流-电压特性,减小了反偏暗电流。利用传输线模型TLM计算得到了Ti/Al/Ti/Au金属电极与高Al组分n-Al0.65Ga0.35N材料间的接触电阻率为8.35×10-3Ωcm2。     

赤泥中浸出铌工艺条件的研究

对拜耳法生产氧化铝的富铌赤泥进行铌的碱浸工艺条件研究,考察赤泥粒度、氢氧化钾浓度、浸出温度、液固比对铌浸出率的影响。结果表明,当赤泥粒度-80μm,氢氧化钾浓度6mol/L,温度260℃,液固比61时,铌的浸出率可达到85%以上。铌的碱浸过程符合收缩未反应芯模型,浸出反应的控制步骤是固膜扩散控制。     

Promoting highly dispersed Co3O4 nanoparticles onto polyethyne unraveling the catalytic mechanism with stable catalytic activity for oxygen evolution reaction: From fundamentals to applications

The solution to overcome the energy crisis in the globe with saving the environment from pollution and the community health, along with other applications of electrochemical for water splitting to get hydrogen and oxygen as a clean fuel. Likewise, the conducting polymers experience as stability over long time, or some time the breaking of conducting polymer chain is unavoidable with addition of polymer. For many reasons, we use noble metal co-catalysts in conjunction with semiconductors for improved hydrogen and oxygen gas production by the water splitting. The morphological characterization, & chemical composition of pristine & composite material studies with the help of different analytical techniques as like SEM, EDX, XRD, XPS & HRTEM. An outperform and active non-noble electrocatalyst for the oxygen evolution reaction which is a hotspot in the current research activities for oxygen & hydrogen production with zero carbon dioxide emission. Herein, we present an advanced material Co₃O₄/polyethyne for the first time to produce oxygen at a reasonable overpotential. The best oxygen evolution performance of Co₃O₄/polyethyne (20) providing the best performance at low overpotential 260 mV at 10 mAcm⁻² the Tafel slope 64 mVdec⁻¹, further strongly acceptable durability approximately for the 30 h & finally obtained charge transfer resistance value of 82.58 Ohms & greater capacitance 1.56 mF value for Co₃O₄. The key element in the success of newly developed catalyst is the greater amount of Co₃O₄ nanoparticles due to selective growth on polyethyne which has played a dominant role in oxygen production. It is because of the worth mentioning properties of polyethyne as a good electrical conductor, as efficient catalyst Co₃O₄ with more surface roughness and high surface area, which is strongly boosting the production of oxygen. The developed material can be applied in other competing fields such as lithium-ion batteries, solar cells, energy storage devices, and photochemical water splitting.     

Self-doped Sargassum spp. derived biocarbon as electrocatalysts for ORR in alkaline media

In this work, high surface area N-doped carbon synthesis from Sargassum spp. is reported as a low cost alternative for electrocatalysts production for the oxygen reduction reaction (ORR). First, Sargassum spp. was activated with potassium hydroxide (SKPH) and then doped with hydrazine (SKPHD). As a result of the activation process, SKPH obtained a high surface area (2289 m² g⁻¹), 0.16% nitrogen and 2.63% sulfur content; it also showed four-electron-transfer mechanism when tested as electrocatalyst in alkaline medium. Besides, SKPHD presented 3.60% nitrogen content in the bulk and higher ORR activity (0.838 V onset potential vs. RHE and 4.59 mA cm⁻² current density) very close to 20% Pt/C (5.25 mA cm⁻²). Results indicate that using seaweeds as a synthesis precursor is an alternative for the Sargassum spp. disposal in the Caribbean due to its high availability and efficiency towards ORR.     

A novel method to tailor the porous structure of KOH-activated biochar and its application in capacitive deionization and energy storage

This study reveals a novel method to tailor the micro- and meso-porous structures of activated biochar by exploiting the interaction between pre-carbonization drying conditions and carbonization temperature in KOH activation. Biochar samples were mixed with concentrated KOH and then dried under air or nitrogen for various periods of time (0–280 h) followed by carbonization at 475, 675 or 875 °C. It is confirmed that by manipulating drying conditions and carbonization temperatures, the KOH activated biochar can have a predominantly microporous, mesoporous or a combined (micro/meso) porous structure. The surface area, micropore and mesopore volumes tailored between: 488–2670 m² g⁻¹, 0.04–0.72 cm³ g⁻¹, and 0.05–1.70 cm³ g⁻¹, respectively. The mechanism of porosity development was investigated by FTIR analysis suggesting conversion of KOH to K₂CO₃ due to different drying conditions as a major role in tailoring the structure. The application of activated biochar with tailored porosity was investigated for Electric Double Layer adsorption of NaCl/NaOH to be employed in water treatment (capacitive deionization) or energy storage (supercapacitor) processes. The majorly microporous activated biochar (N₂-dried activated at 675 °C) showed promising capacitances between 220 and 245 F g⁻¹. Addition of mesoporous structure resulted in capacitances between 182 and 240 F g⁻¹ with significantly reduced electrode resistance and improved capacitive behavior as evidenced by Impedance Spectroscopy and Galvanostatic Charge/Discharge tests.     

Dimethyl Sulfoxide/Potassium Hydroxide: A Superbase for the Transition Metal‐Free Preparation of Cross‐Coupling Products

Potassium hydroxide (KOH) in dimethyl sulfoxide (DMSO) forms a superbasic medium that allows one to access cross‐coupling products from reactions between aryl halides with various sulfur‐, oxygen‐ and nitrogen‐based nucleophiles under transition metal‐free conditions.     

水电解制氢系统碱液倒串事故分析及其防范措施

从工艺机理的角度分析了水电解制氢系统碱液倒串事故的原因,并进行了工艺优化改造,同时总结教训,制定了相关防范措施。     

KOH activation of pitch-derived carbonaceous materials—Effect of carbonization degree

Two series of mesophase pitches and semi-cokes of different carbonization degree were produced by heat treatment of anthracene oil derived pitches P1 and P4 in the temperature range of 460-700 °C. These carbonaceous materials were activated with potassium hydroxide at 700 °C using 1:3 reagents ratio to assess the effects of the precursor optical texture and carbonization degree on the activation behavior. The results show that the increase in the pitch pretreatment temperature suppresses propensity to the pore generation while enhancing particle breaking. The effect can be illustrated by decreases in the BET surface area S_BET from ~ 2700 to ~ 1500 m² g⁻¹ and the micropore volume V_DR from ~ 0.85 to ~ 0.45 cm³ g⁻¹. These parameters are inversely related with the H/C atomic ratio of precursor. In contrast, the anisotropic development of pitch coke, varying from flow type to mosaics, has a slight effect on the activation behaviour. The mechanism of porosity generation, that is proposed, stresses the role of hydrogen occurring at the edges of graphene layers and potassium metal insertion/deinsertion on the porosity development and particle disintegration during KOH activation of pitch-derived carbons.     

低钠保健皮蛋加工技术研究

在传统加工方法的基础上,利用KOH代替NaOH,并用KCl部分代替NaCl,加工低钠保健松花蛋,钠含量由465.8mg/100g降至287.6mg/100g,降幅为38.27%.本课题初步摸清了低钠无铅松花蛋的工艺要点,并测试了蛋中Na+、K+、Cu2+、Zn2+和碱浓度的变化情况.