基于Pd催化氧化处理生活垃圾渗沥液MBR出水的试验研究

针对生活垃圾渗沥液MBR出水,构建了Pd催化氧化反应系统,设计了三相反应体系,分析反应流程,确定了主要的体系反应参数,得出了动态条件下的渗沥液处理效果。研究发现:本体系从吹脱、吸附和羟基自由基氧化3个方面进行渗沥液中难降解物质的处理,反应过程分为快速降解段、吸附饱和段、继续反应段和反应平稳段4个阶段。装置的最佳条件为:在气速30.00 mL/min、液速2.00 mL/min时,反应能够达到最佳的COD去除效率为73.22%,氨氮处理效率为82.33%。在整个反应流程中,前15 min内COD处理效果明显,占总的COD处理率的34.24%。

甘油在氧化物/钯复合催化剂上的电氧化研究

应用交替微波加热法制备碳载氧化物和Pd的复合催化剂,并以电化学方法研究这一新型催化剂在碱性条件下对甘油的氧化性能.实验表明,Pd/C催化剂对甘油的电化学氧化有较好活性,但氧化物复合的非铂催化剂对甘油的电化学氧化显示出更高的活性,相对于Pd/C催化剂,其氧化起始电位发生负移及峰电流大幅度提高.本工作还优化了氧化物与Pd的比例.结果证明,氧化物的加入使复合催化剂对甘油氧化产生了协同效应.

Structure-activity relationship in Pd/CeO2 methane oxidation catalysts

Palladium based catalysts are the most active for methane oxidation. The tuning of their composition, structure and morphology at macro and nanoscale can alter significantly their catalytic behavior and robustness with a strong impact on their overall performances. Among the several combinations of supports and promoters that have been utilized, Pd/CeO2 has attracted a great attention due to its activity and durability coupled with the unusually high degree of interaction between Pd/Pd O and the support. This allows the creation of specific structural arrangements which profoundly impact on methane activation characteristics. Here we want to review the latest findings in this area, and particularly to envisage how the control(when possible) of Pd-CeO2 interaction at nanoscale can help in designing more robust methane oxidation catalysts.

FeOx Coating on Pd/C Catalyst by Atomic Layer Deposition Enhances the Catalytic Activity in Dehydrogenation of Formic Acid

Hydrogen generation from formic acid （FA） has received significant attention. The challenge is to obtain a highly active catalyst under mild conditions for practical applications. Here atomic layer deposition （ALD） of FeOx was performed to deposit an ultrathin oxide coating layer to a Pd/C catalyst, therein the FeOx coverage was precisely controlled by ALD cycles. Transmission electron microscopy and powder X-ray diffraction measurements suggest that the FeOx coating layer improved the thermal stability of Pd nanoparticles （NPs）. X-ray photoelectron spectroscopy measurement showed that deposition of FeOx on the Pd NPs caused a positive shift of Pd3d binding energy. In the FA dehydrogenation reaction, the ultrathin FeOx layer on the Pd/C could considerably improve the catalytic activity, and Pd/C coated with 8 cycles of FeOx showed an optimized activity with turnover frequency being about 2 times higher than the uncoated one. shape as a function of the number of FeOx ALD The improved activities were in a volcanocycles, indicating the coverage of FeOx is critical for the optimized activity. In summary, simultaneous improvements of activity and thermal stability of Pd/C catalyst by ultra-thin FeOx overlayer suggest to be an effective way to design active catalysts for the FA dehydrogenation reaction.

Facile synthesis of 3D nanoporous Pd/Co_2O_3 composites with enhanced catalytic performance for methanol oxidation

To simultaneously reduce noble metal Pd usage and enhance electrocatalytic performance for methanol oxidation,Pd/Co2O3 composites with ultrafine three-dimensional(3D)nanoporous structures were designed and synthesized by simple one-step dealloying of a melt-spun Al-Pd-Co alloy with an alkaline solution.Their electrocatalytic activity in alkaline media was determined by a Versa-STAT MC workstation.The results indicate that the typical sizes of the ligaments and pores of the composites were approximately 8-9 nm.The Co2O3 was uniformly distributed on the Pd ligament surface.Among the as-prepared samples,the nanoporous Pd/Co2O3 composite generated from dealloying of the Al84.5Pd15Co0.5 alloy had the best electrocatalytic activity,and its activity was enhanced by approximately 230%compared with the nanoporous Pd from dealloying of Al85Pd15.The improvement of the electrocatalytic performance was mainly attributed to the electronic modification effect between Pd and Co as well as the bifunctional mechanism between Pd and Co2O3.

Synthesis of Pd（C4H2O4）（C4H8N2）0.5 Complex and the Catalytic Activity for Oxidative Carbonylation of Phenol

A novel complex Pd（C4H2O4）（C4H8N2）0.5 has been synthesized by solvent thermal synthesis and used as a heterogeneous catalyst for direct synthesis of diphenyl carbonate （DPC） by oxidative carbonylation of phenol. In the reaction system of Pd（C4H2O4）（C4H8N2）0.5/Cu（OAc）2/ tetrabutylammonium bromide/ hydroquinone/ 4A molecular sieves, the effect of reaction temperature, time and CO pressure on catalytic activity were investigated, and the results revealed that the catalyst could catalyze oxidative carbonylation of phenol effectively. Under suitable reaction conditions of T=90℃, t=4 h, p（O2）=0.3 MPa, p（CO）=3.9 MPa and CH2Cl2 as solvent, the turnover number （TON） of diphenyl carbonate can reach about 13.50 （mol-DPC/mol-Pd）, which is higher than the TON for oure PdCl2 under the same reaction conditions.

Catalytic performance of cobalt oxide-supported gold-palladium nanocatalysts for the removal of toluene and o-xylene

Using the molten salt and polyvinyl alcohol-protected reduction method,we fabricated Co3O4 octahedron-supported Au-Pd（x（AuPdy）/Co3O4;x =（0.18,0.47,and 0.96） wt%;y（Pd/Au molar ratio） =1.85-1.97） nanocatalysts.The molten salt-derived Co3O4 sample possessed well-defined octahedral morphology,with an edge length of 300 nm.The Au-Pd nanoparticles,with sizes of 2.7-3.2 nm,were uniformly dispersed on the surface of Co3O4.The 0.96（AuPd1.92）/Co3O4 sample showed the highest catalytic activity for toluene and o-xylene oxidation,and the temperature required for achieving 90%conversion of toluene and o-xylene was 180 and 187 ℃,respectively,at a space velocity of 40000 mL/（g·h）.The high catalytic performance of Co3O4 octahedron-supported Au-Pd nanocatalysts was associated with the interaction between Au-Pd nanoparticles and Co3O4 and high concentration of adsorbed oxygen species.

果糖嗪的合成及抗衰老评价

以D-葡萄糖为原料,通过Amadori重排、异丙叉基保护、Pd/C催化加氢脱苄基和氧化芳构化串联反应、脱异丙叉保护4步反应得到果糖嗪,HPLC纯度达96%。使用NMR、MS、X射线单晶衍射技术对关键中间体异丙叉基果糖嗪的结构进行了表征。使用噻唑蓝(MTT)法测定果糖嗪对人胚肺二倍体成纤维细胞(2BS细胞)活力的影响,筛选获得最佳培养浓度为1μmol/L,可以上调细胞活力,为对照组的125%。采用细胞衰老β-半乳糖苷酶(SA-β-Gal)染色法对果糖嗪的抗衰老活性进行了评价,以1μmol/L果糖嗪连续传代培养衰老早期细胞和衰老中期细胞,其蓝染率比对照组分别降低了14%和19%。实验表明,果糖嗪对衰老早期或中期的2BS细胞都有抗衰老活性。

The study of the active surface for CO oxidation over supported Pd catalysts

CO oxidation was investigated on various powder oxide supported Pd catalysts by temperature-programined reaction. The pre-reduced catalysts show significantly higher activities than the pre-oxidized ones. Model studies were performed to better understand the oxidation state, reactivities and stabilities of partially oxidized Pd surfaces under CO oxidation reaction condi tions using an in situ infrared reflection absorption spectrometer （IRAS）. Three O/Pd（100） model surfaces, chemisorbed oxygen covered surface, surface oxide and bulk-like surface oxide, were prepared and characterized by low-energy electron diffraction （LEED） and Auger electron spectroscopy （AES）. The present work demonstrates that the oxidized palladium surface is less active for CO oxidation than the metallic surface, and is unstable under the reaction conditions with sufficient CO.