A dendritic Cu/Cu_(2)O structure with high curvature enables rapid and efficient reduction of carbon dioxide to C_(2) in an H-cell

Electrocatalytic reduction of CO_(2)(CO_(2)RR)to multicarbon products is an efficient approach for ad-dressing the energy crisis and achieving carbon neutrality.In H-cells,achieving high-current C_(2)products is challenging because of the inefficient mass transfer of the catalyst and the presence of the hydrogen evolution reaction(HER).In this study,dendritic Cu/Cu_(2)O with abundant Cu^(0)/Cu^(+)interfaces and numerous dendritic curves was synthesized in a CO_(2)atmosphere,resulting in the high selectivity and current density of the C_(2)products.Dendritic Cu/Cu_(2)O achieved a C_(2)Faradaic efficiency of 69.8%and a C_(2)partial current density of 129.5 mA cm^(-2)in an H-cell.Finite element simulations showed that a dendritic structure with a high curvature generates a strong electric field,leading to a localized CO_(2)concentration.Additionally,DRT analysis showed that a dendritic struc-ture with a high curvature actively adsorbed the surrounding high concentration of CO_(2),enhancing the mass transfer rate and achieving a high current density.During the experiment,the impact of the electronic structure on the performance of the catalyst was investigated by varying the atomic ratio of Cu^(0)/Cu^(+) on the catalyst surface,which resulted in improved ethylene selectivity.Under the optimal atomic ratio of Cu^(0)/Cu^(+),the charge transfer resistance was minimized,and the desorption rate of the intermediates was low,favoring C_(2) generation.Density functional theory calculations indicated that the Cu^(0)/Cu^(+) interfaces exhibited a lower Gibbs free energy for the rate-determining step,enhancing C_(2)H_(4) formation.The Cu/Cu_(2)O catalyst also exhibited a low Cu d-band center,which enhanced the adsorption stability of *CO on the surface and facilitated C_(2)formation.This observa-tion explained the higher yield of C_(2) products at the Cu^(0)/Cu^(+) interface than that of H_(2) under rapid mass transfer.The results of the net present value model showed that the H-cell holds promising industrial prospects,contingent upon it being a catalyst with both high selectivity and high current density.This approach of integrating the structure and composition provides new insights for ad-vancing the CO_(2)RR towards high-current C_(2) products.

Effects of zinc on χ-Fe_(5)C_(2) for carbon dioxide hydrogenation to olefins:Insights from experimental and density function theory calculations

Production of light olefins from CO_(2), the primary greenhouse gases, is of great importance to mitigate the adverse effects of CO_(2) emission on environment and to supply the value-added products from nonpetroleum resource. However, development of robust catalyst with controllable selectivity and stability remains a challenge. Herein, we report that Zn-promoted Fe catalyst can boost the stable and selective production of light olefins from CO_(2). Specifically, the Zn-promoted Fe exhibits a highly stable activity and olefin selectivity over 200 h time-on-stream compared to the unpromoted Fe catalyst, primarily owing to the preservation of active χ-Fe_(5)C_(2) phase. Structural characterizations of the spent catalysts suggest that Zn substantially regulates the content of iron carbide on the surface and suppresses the reoxidation of bulk iron carbide during the reaction. DFT calculations confirm that adsorption of surface carbon atoms and graphene-like carbonaceous species are not thermochemically favored on Zn-promoted Fe catalyst. Carbon deposition by CAC coupling reactions of two surface carbon atoms and dehydrogenation of CH intermediate are also inhibited. Furthermore, the effects of Zn on antioxidation of iron carbide were also investigated. Zn favored the hydrogenation of surface adsorbed oxygen atoms to H_(2)O and the desorption of H_(2)O, which reduces the possibility of surface carbide being oxidized by the chemisorbed oxygen.

Photocatalytic reduction of carbon dioxide to methanol by Cu_2O/SiC nanocrystallite under visible light irradiation

The Cu2O/SiC photocatalyst was obtained from SiC nanoparticles （NPs） modified by Cu2O. Their photocatalytic activities for reducing CO2 to CH3OH under visible light irradiation have been investigated. The results indicated that besides a small quantity of 6H-SiC, SiC NPs mainly consisted of 3C-SiC. The band gaps of SiC and Cu2O were estimated to be about 1.95 and 2.23 eV from UV-Vis spectra, respectively. The Cu2O modification can enhance the photocatalytic performance of SiC NPs, and the largest yields of methanol on SiC, Cu2O and Cu2O/SiC photocatalysts under visible light irradiation were 153, 104 and 191μmol/g, respectively.

Carbon dioxide reforming of methane on monolithic Ni/Al_2O_3-based catalysts

Nickel-alumina catalysts supported on cordierite monoliths of honeycomb structure surpass essentially the conventional granulated ones with respect to the output in carbon dioxide reforming of methane. Adjusting the surface acid-base properties of catalysts by introduction of alkali metal （Na, K） oxides inhibits the carbonization and as a result, improves the operational stability of these catalysts. An effect of promotion of nickel-alumina based composite doped by lanthanum oxide is found. This effect, caused by an additional route for the CO2 activation on Ni-La2O3/Al2O3/cordierite catalyst, is displayed in increase of methane conversion under conditions of an oxidant excess.

Kinetics of Reactive Extraction of Nd from Nd2O3 with TBP-HNO3 Complex in Supercritical Carbon Dioxide

The process based on supercritical fluid extraction for reprocessing of the spent nuclear fuel has some remarkable advantages over the plutonium-uranium extraction(PUREX) process.Especially,it can minimize the generation of secondary waste.Dynamic reactive extraction of neodymium oxide(Nd2O3) in supercritical carbon dioxide(SC-CO2) containing tri-n-butyl phosphate-nitric acid(TBP-HNO3) complex was investigated.Temperature showed a positive effect on the extraction efficiency,while pressure showed a negative effect when the unsaturated TBP-HNO3 complex was employed for the dynamic reactive extraction of Nd2O3 in SC-CO2.Both temperature and pressure effects indicated that the kinetic process of the reactive extraction was controlled by the chemical reaction.A kinetic model was proposed to describe the extraction process.

Syngas production by combined carbon dioxide reforming and partial oxidation of methane over Ni/α-Al_2O_3 catalysts

Ni/α-Al2O3 catalysts were found to be active in the temperature range 600 ～ 900℃ for both CO2 reforming and partial oxidation of methane.The effects of Ni loading,reaction temperature and feed gas ratio for the combination of CO2 reforming and partial oxidation of CH4 over Ni/α-Al2O3 were investigated.Catalysts of xwt%Ni/α-Al2O3（x=2.5,5,8 and 12） were prepared by wet impregnating the calcined support with a solution of nickel nitrate.XRD patterns and activity tests have verified that the 5wt%Ni/α-Al2O3 was the most active catalyst,as compared with the other prepared catalyst samples.An increase of the Ni loading to more than 5wt% led to a reduction in the Ni dispersion.In addition,by combining the endothermic carbon dioxide reforming reaction with the exothermic partial oxidation reaction,the loss of catalyst activity with time on stream was reduced with the amount of oxygen added to the feed.

Low temperature H_2S sensor based on copper oxide/tin dioxide thick film

Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.

改性硫化钼催化剂协同低温等离子体转化H_(2)S-CO_(2)酸气制合成气的研究

以低温等离子体和催化剂耦合法将H_(2)S和CO_(2)混合酸气一步转化为合成气,既完成了两者清洁化处理,又实现了资源化利用,是一条制备合成气的新路线。本研究采用铜、锌为助剂对硫化钼催化剂改性,显著提升了其催化H_(2)S-CO_(2)制合成气反应性能。结合多种分析表征手段对比两种助剂引入后对硫化钼催化剂结构、组成、形貌、化合价态等物化特征的影响。通过控制低温等离子体放电条件,深入探究了两种助剂对低温等离子体下催化转化H_(2)S和CO_(2)酸气制合成气的反应性能影响规律和关键因素。研究发现,引入铜、锌助剂后,硫化钼活性相粒径减小且分散度高,提供了更多活性位点。同时也增强了对H_(2)S和CO_(2)分子吸附强度,从而更利于H_(2)S和CO_(2)分子的吸附活化,揭示出低温等离子体与改性硫化钼催化剂协同反应的构效关联。有关理论研究丰富拓展了低温等离子体-催化协同理论,并为改性硫化钼材料的合成提供借鉴。

Effect of Exogenous Hydrogen Sulfide(H_2S) on the Electrocardiogram(ECG) of Rats Generally Anaesthetized by Zoletil

Hydrogen sulfide （H2S） is the third gaseous signaling molecule discovered in recent years, and plays an important physiological role in the cardivascular system. To explore the effects of different doses of exogenous H2S on the electrocardiogram （ECG） of rats generally anesthetized by zoletil, different doses of NariS solution were used for the intervention of intraperitoneal injection 20 rain before the zoletil anesthesia. The ECGs of rats from each treatment group during the time range of 10^th-50^th min were determined under general anesthesia, and then were compared with those from the control group. The results showed that exogenous H2S could significantly reduce the Q-T interval time limit, thus played a role in slowing tachycardia or arrhythmia and other anomalies, thereby protecting the heart. S-T segment and T segment evaluation values were significantly reduced, which might be associated with bradycardia.

构建双通道路径增强iCOF/Bi_(2)O_(3)S型异质结在纯水体系中光催化合成H2O2性能

太阳能光催化技术是一种绿色、经济、可持续的制备H_(2)O_(2)方法,被认为是取代传统蒽醌法最有前景的策略。然而,由于有限的光捕获能力、快速的光生载流子复合以及氧化还原能力不足等问题,单一组分光催化剂表现出温和的光催化活性。并且,在光催化合成H_(2)O_(2)反应系统中需要额外添加牺牲剂。在这项研究中,我们通过光沉积法将Bi_(2)O_(3)(BO)纳米颗粒负载于离子型有机共价框架材料(iCOF)纳米纤维上,构建一种S型异质结用于双通道路径光催化合成H_(2)O_(2)。在纯水体系中,在iCOF表面负载10 wt%BO时,复合催化剂iCOF/BO10表现出最高的H_(2)O_(2)产率,达到了9.76 mmol·g^(-1)·h^(-1)(在420 nm处的量子效率为5.5%)。这一性能分别是纯iCOF的2.2倍,纯BO的5.6倍。原位表征技术(包括原位X射线光电子能谱、DFT理论计算、活性物种捕获实验以及原位漫反射红外傅里叶变换光谱)揭示该S型异质结不仅能促进光生载流子的分离和增强光吸收能力,而且能实现氧化还原能力最大化,使得反应体系同时通过间接2e^(-)氧气还原反应和4e^(-)水氧化反应双通道路径产生H_(2)O_(2)。此外,4e^(-)水氧化反应生成的O_(2)能够通过间接2e^(-)氧气还原反应加快H_(2)O_(2)生成的反应动力学,实现光催化H_(2)O_(2)的全合成。该项工作为开发新颖催化剂实现高效光催化合成H2O_(2)提供了独特的见解。

C6H10S2O联合Nano-CaCO3对铅染毒小鼠海马学习记忆功能的影响

评价 C6H10S2O联合Nano-CaCO3对铅染毒小鼠的海马学习记忆功能产生的影响,以指导铅染毒相关问题的处理。方法 选择齐齐哈尔医学院动物实验中心提供的20-30g 健康雌性 KM 小鼠,健康清洁级,分为正常对照组、模型对照组、C6H10S2O 组、Nano-CaCO3组、联合治疗组,其中后四组均为铅染毒模型。五组的饲养条件相同,方法 /剂量建立铅染毒模型,提供对应治疗方法,通过评估体质量与血液中铅元素含量、NO含量和ACHE活力、水迷宫、新物体识别测量的结果,判断治疗效果。结果 与空白对照组比较,模型对照组的体质量显著降低(P<0.05),血铅含量显著增加(P<0.05);与模型对照组比较,C6H10S2O组和联合治疗组小鼠的体质量显著提高(P<0.05),而血铅含量仅在联合治疗组显著减少(P<0.05);其他三组的体质量和血铅含量均无统计学差异(P>0.05)。与模型对照组比较,联合治疗组的跨越隐匿平台次数和平台象限游泳路程显著增加(P<0.05);与Nano-CaCO3组比较,联合治疗组的跨越隐匿平台次数和平台象限游泳路程也显著增加(P<0.05)。五组在NO含量和ACHE活力、认知指数方面的对比,差异均不存在统计学意义(P>0.05)。结论 C6H10S2O联合Nano-CaCO3可以减少铅含量,提高体质量,对空间学习能力有一定影响,但对认知能力、学习记忆能力不存在显著影响。

Selective hydrogenation of CO2 to methanol over Ni/In2O3 catalyst

An In2O3 supported nickel catalyst has been prepared by wet chemical reduction with sodium borohydride(NaBH4) as a reducing agent for selective hydrogenation of carbon dioxide to methanol. Highly dispersed Ni species with intense Ni-In2O3 interaction and enhanced oxygen vacancies have been achieved.The highly dispersed Ni species serve as the active sites for hydrogen activation and hydrogen spillover.Abundant H adatoms are thereby generated for the oxygen vacancy creation on the In2O3 surface. The enhanced surface oxygen vacancies further lead to improved CO2 conversion. As a result, an effective synergy between the active Ni sites and surface oxygen vacancies on In2O3 causes a superior catalytic performance for CO2 hydrogenation with high methanol selectivity. Carbon monoxide is the only by product detected. The formation of methane can be ignored. When the reaction temperature is lower than 225 ℃,the selectivity of methanol is 100%. It is higher than 64% at the temperature range between 225 ℃ and 275 ℃. The methanol selectivity is still higher than 54% at 300 ℃ with a CO2 conversion of 18.47% and a methanol yield of 0.55 gMeOHg-1cath-1(at 5 MPa). The activity of Ni/In2O3 is higher than most of the reported In2O3-based catalysts.

Effects of ZrO_2 on the Performance of CuO-ZnO-Al_2O_3/HZSM-5 Catalyst for Dimethyl Ether Synthesis from CO_2 Hydrogenation

A series of composite catalysts were prepared by the wet mixing method, and the mass ratio of CuO-ZnO-Al2O3-ZrO2 component to HZSM-5 zeolite （molar ratio of SiO2 to Al2O3 being 25） was 2：1. The CuO-ZnO-Al2O3-ZrO2 （CuO/ZnO/Al2O3=3/6/1 by weight） component was prepared by a modified ＇two-step＇ co-precipitation method. The effects of ZrO2 on the performance of CuO-ZnO-Al2O3/HZSMo5 catalyst for dimethyl ether synthesis from CO2 hydrogenation were investigated. It was found that ZrO2 improved the properties of CuO-ZnO-Al2O3/HZSM-5 as a structural promoter.

2-Ethyl-9,10-anthraquinone assisted sol–gel synthesis of Pd/γ-Al2O3 nanorods with enhanced catalytic performance in 2-ethyl-9,10-anthraquinone hydrogenation

A series of nanorod-like porous Pd/γ-Al2 O3 catalysts with controllable textural properties and enhanced catalytic performance in 2-ethyl-9,10-anthraquinone(eAQ) hydrogenation for H2 O2 preparation were successfully prepared via a facile sol-gel method using aluminum isopropoxide as aluminum precursor and eAQ as structure directing agent,sequential calcination and impregnation process with Na2 PdCl4 solution.The physicochemical properties of the catalysts obtained with different addition amounts of eAQ.were comparatively characterized by XRD,TG-DSC,BET,TEM,CO-TPR,H2-TPR and H2-O2 titration.The results show that addition of eAQ can not only effectively control the textural properties(surface area,pore volume and average pore size) of the catalysts,but also lower their reduction temperature of active metal.Importantly,the catalyst obtained with an addition amount of 4 wt% eAQ shows the highest hydrogenation efficiency of 10.28 g·L^-1,which is 37.3% higher than 7.49 g·L^-1 of the catalyst obtained without eAQ.

Synthesis of core-shell nanostructured Cr2O3/C@TiO2 for photocatalytic hydrogen production

In this study,the Cr2O3/C@TiO2 composite was synthesized via the calcination of yolk–shell MIL-101@TiO2.The composite presented core–shell structure,where Cr-doped TiO2 and Cr2O3/C were the shell and core,respectively.The introduction of Cr^3+and Cr2O3/C,which were derived from the calcination of MIL-101,in the composite enhanced its visible light absorbing ability and lowered the recombination rate of the photogenerated electrons and holes.The large surface area of the Cr2O3/C@TiO2 composite provided numerous active sites for the photoreduction reaction.Consequently,the photocatalytic performance of the composite for the production of H2 was better than that of pure TiO2.Under the irradiation of a 300 W Xe arc lamp,the H2 production rate of the Cr2O3/C@TiO2 composite that was calcined at 500°C was 446μmol h−1 g−1,which was approximately four times higher than that of pristine TiO2 nanoparticles.Moreover,the composite exhibited the high H2 production rate of 25.5μmol h−1 g−1 under visible light irradiation(λ>420 nm).The high photocatalytic performance of Cr2O3/C@TiO2 could be attributed to its wide visible light photoresponse range and efficient separation of photogenerated electrons and holes.This paper offers some insights into the design of a novel efficient photocatalyst for water-splitting applications.

Catalytic methanol decomposition to carbon monoxide and hydrogen over Pd/CeO_2-ZrO_2-La_2O_3 with different Ce/Zr molar ratios

Hairong Wang, Yaoqiang Chen, Qiulin Zhang, Qingchao Zhu, Maochu Gong, Ming Zhao（ Key Laboratory of Green Chemistry ＆ Technology of Ministry Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China

Highly stable and selective Ru/NiFe2O4 catalysts for transfer hydrogenation of biomass-derived furfural to 2-methylfuran

Spinel ferrites NiFeOsupported Ru catalysts have been prepared via a simple sol–gel route and applied for converting biomass-derived furfural to 2-methylfuran. The as-prepared catalysts were characterized by thermogravimetric analysis（TG）, Nadsorption–desorption, X-ray diffraction（XRD）, scanning electronic microscopy（SEM）, and X-ray photoelectron spectroscopy（XPS）. Results showed that the catalysts had well-dispersed Ru active sites and large surface area for calcination temperature ranging from 300 to 500 ℃. The conversion of biomass-derived furfural into 2-methylfuran was conducted over Ru/NiFeOthrough catalytic transfer hydrogenation in liquid-phase with 2-propanol as the hydrogen source. A significantly enhanced activity and increased 2-methylfuran yield have been achieved in this study. Under mild conditions（180 ℃ and 2.1 MPa N）, the conversion of furfural exceeds 97% and 2-methylfuran yield was up to 83% over the catalyst containing 8 wt% Ru. After five repeated uses, the catalytic activity and the corresponding product yield remained almost unchanged. The excellent catalytic activity and recycling performance provide a broad prospects for various practical applications.

Amorphous TiO_2-modified CuBi_2O_4 Photocathode with enhanced photoelectrochemical hydrogen production activity

In this study,CuBi2O4 photocathodes were prepared using a simple electrodeposition method for photoelectrochemical(PEC)hydrogen production.The prepared photocathodes were modified with amorphous TiO2 and a Pt co‐catalyst,which resulted in the formation of CuBi2O4/TiO2 p‐n heterojunctions,and enhanced the activities of the as‐prepared photocathodes.The novel Pt/TiO2/CuBi2O4 photocathode exhibited a photocurrent of 0.35 mA/cm2 at 0.60 V vs.Reversible Hydrogen Electrode(RHE),which was nearly twice that of the Pt/CuBi2O4 photocathode.The present study provides a facile method for increasing the efficiency of photocathodes and provides meaningful guidance for the preparation of high‐performance CuBi2O4 photocathodes.

The nature of the deactivation of hydrothermally stable Ni/SiO2–Al2O3 catalyst in long-time aqueous phase hydrogenation of crude 1,4-butanediol

The deactivation of Ni/SiO2-Al2 O3 catalyst in hydrogenation of crude 1,4-butanediol was investigated.During the operation time of 2140 h,the catalyst showed slow activity decay.Characterization results,for four spent catalysts used at different time,indicated that the main reason of the catalyst deactivation was the deposition of carbonaceous species that covered the active Ni and blocked mesopores of the catalyst.The TPO and SEM measurements revealed that the carbonaceous species included both oligomeric and polymeric species with high C/H ratio and showed sheet.Such carbonaceous species might be eliminated through either direct H2 reduction or the combined oxidation-reduction methodologies.

Effect of Alumina Particle Size on Ni/Al2O3 Catalysts for p-Nitrophenol Hydrogenation

The catalytic hydrogenation of p-nitrophenol to p-aminophenol was investigated over Ni/Al2O3 catalyst on alumina support with different particle size. It is found that support particle size has significant influences on physiochemical properties and catalytic activity of the resulting Ni/Al2O3 catalyst, but little influence on the selec-tivity. At a comparable amount of Ni loading, the catalytic activity of Ni/Al2O3 prepared with alumina support of smaller particle size is lower. The reduction behavior of the catalyst is a key factor in determining the catalytic activity of Ni/Al2O3 catalyst. The supported nickel catalyst 10.3Ni/Al2O3-3 improves the life span of the membrane by reducing fouling on the membrane surface compared to nano-sized nickel.