Enhanced ethanol electro-oxidation on CeO_2-modified Pt/Ni catalysts in alkaline solution

Pt/Ni catalysts modified with CeO2 nanoparticles were prepared by simple composite electrodeposition of Ni and CeO2,and spontaneous Ni partial replacement by Pt processes.The as-prepared CeO2-modified Pt/Ni catalysts showed enhanced catalytic performance for ethanol electro-oxidation compared with pure Pt/Ni,and acetate species were proposed to be the main products of the oxidation when using these catalysts.The content of CeO2 in the as-prepared catalysts influenced their catalytic activity,with Pt/NiCe2（obtained from an electrolyte containing 100 mg/L CeO2 nanoparticles） exhibiting higher activity and relatively better stability in ethanol electro-oxidation.This was mainly due to the oxygen storage capacity of CeO2,the interaction between Pt and CeO2/Ni,and the relatively small contact and charge transfer resistances.The results of this work thus suggest that electrocatalysts with low price and high activity can be rationally designed and produced by a simple route for use in direct ethanol fuel cells.

Preparation and characterization of Pt-WO_3/C catalysts for direct ethanol fuel cells

Three co-impregnation/chemical reduction methods in acidic solutions of pH 〈 1,including ethylene glycol （EG）,NaBH4,and HCOOH,were compared for Pt-WO3/C catalysts.Pt-WO3/C catalysts containing 10 wt.% and 20 wt.% platinum per carbon were prepared by the three methods; their morphology and electrocatalytic activities were characterized.The 20 wt.% Pt-WO3/C catalyst prepared by the co-impregnation/EG method presented the optimal dispersion with an average particle size of 4.6 nm and subsequently the best electrocatalytic activity,and so,it was further characterized.Its anodic peak current density for ethanol oxidation from linear sweep voltammetry （LSV） is 7.9 mA·cm^-2,which is 1.4 and 5.2 times as high as those of the catalysts prepared by co-impregnation/NaBH4 and co-impregnation/ HCOOH reduction methods,2.1 times as high as that of the 10 wt.% Pt-WO3/C catalyst prepared by co-impregnation/EG method,respectively.

Synthesis and characterization of Pt-MoO_x-TiO_2 electrodes for direct ethanol fuel cells

To enhance the CO-tolerance performance of anode catalysts for direct ethanol fuel cells,carbon nanotubes were modified by titanium dioxide （donated as CNTs@TiO2） and subsequently served as the support for the preparation of Pt/CNTs@TiO2 and Pt-Mo/CNTs@TiO2 electrocatalysts via a UV-photoreduction method.The physicochemical characterizations of the catalysts were carried out by using X-ray diffraction （XRD）,transmission electron microscopy （TEM）,X-ray photoelectron spectroscopy （XPS）,and infrared spectroscopy of adsorbed probe ammonia molecules.The electrocatalytic properties of the catalysts for methanol oxidation were investigated by the cyclic voltammetry technique.The results show that Pt-Mo/CNTs@TiO2 electrode exhibits the highest performance in all the electrodes.It is explained that,the structure,the oxidation states,and the acid-base properties of the catalysts are influenced due to the strong interaction between Ti and Mo species by adding TiO2 and MoOx to the Pt-based catalysts.

The Control of Lactobacillus sp.by Extracellular Compound Produced by Pseudomonas aeruginosa in the Fermentation Process of Fuel Ethanol Industry in Brazil

This work evaluated the effect of secondary bacterial metabolites produced by Pseudomonas sp LV strain in control of Lactobacillus sp. population in the microcosm of the vat during ethanol fermentation. The fraction F4 produced by Pseudomonas aeruginosa was extracted with dichloromethane and fractionating by vacuum liquid chromatography obtained in a methanol phase. The evaluation of antibiotic activity of F4 fraction mixed or not with sulphuric acid and Kamoram?. The antibiotic activity of F4 fraction was determined as well as the fermentation efficiency. Also was determined yeast cell viability, budding formation, the viability of budding cells, and number of populations of Saccharomyces cerevisiae and Lactobacillus sp. The results showed that the F4 fraction had high selective antibiotic activity against Lactobacillus sp. but not for S. cerevisae, and no inhibitory effect was observed in the fermentation process by yeast. Also F4 fraction decreased flocculation and foam formation. The F4 has an antibiotic activity against Lactobacillus sp. and should be used as an alternative to control bacteria contamination and foam and flocculation formation in the fuel ethanol fermentation process. The F4 fraction could reduce the use of antibiotics in the control of Lactobacillus sp. population during the fuel ethanol production.

Sorghum as Dry Land Feedstock for Fuel Ethanol Production

Dry land crops such as sorghums （grain sorghum, promising feedstocks for fuel ethanol production. The major issue sweet sorghum and forage sorghum） have been identified as for using the sweet sorghum as feedstock is its stability at room temperature. At room temperature, the sweet sorghum juice could lose from 40% to 50% of its fermentable sugars from 7 to 14 days No significant sugar content and profile changes were observed in juice stored at refrigerator temperature in two weeks. Ethanol fermentation efficiencies of fresh and frozen juice were high （-93%）. Concentrated juice （≥25% sugar） had significantly lower efficiencies and large amounts of fructose left in finished beer; however, winery yeast strains and novel fermentation techniques may solve these problems. The ethanol yield from sorghum grain increased as starch content increased. No linear relationship between starch content and fermentation efficiency was found. Key factors affecting the ethanol fermentation efficiency of sorghum include starches and protein digestibility, amylose-lipid complexes, tannin content, and mash viscosity. Life cycle analysis showed a positive net energy value （NEV） = 25 500 Btu/gal ethanol. Fourier transform infrared （FTIR） spectroscopy and X-ray diffraction （XRD） were used to determine changes in the structure and chemical composition of sorghum biomasses. Dilute sulfuric acid pretreatment was effective in removing the hemicellulose from biomasses and exposing the cellulose for enzymatic hydrolysis. Forage sorghum lignin had a lower syringyl/guaiacyl ratio and its pretreated biomass was easier to hydrolyze. Up to 72% hexose yield and 94% pentose yield were obtained by using a modified steam explosion with 2% sulfuric acid at 140℃ for 30 min and enzymatic hydrolysis with cellulase.

Allocation of Energy Use in the Biomass-based Fuel Ethanol System and Its Use in Decision Making

The Chinese government is developing biomass ethanol as one of its automobile fuels for energy security and environmental improvement reasons. The energy efficiency of the biomass-based fuel ethanol is critical issue. To investigate the energy use in the three biomass-base ethanol fuel systems, energy content approach, Market value approach and Product displacement approach methods were used to allocate the energy use based on life cycle energy assessment. The results shows that the net energy of corn based, wheat based, and cassava-based ethanol fuel are 12543MJ, 10299MJ and 13112MJ when get one ton biomassbased ethanol, respectively, and they do produce positive net energy.

Simulation of the Strip-Flash Ethanol Continuous Fermentation Process

The conventional ethanol fermentaion is a typical inhibitory process, leading to low productivity and yield. A new ethanol fermentation process coupled with gas stripping and vacuum fash, named as strip-flash fermentation, is proposed. The process is provided with the advantages of both stripping fermentation and flash fermentation, and improves the ethanol productivity by increasing the in-situ ethanol removal. And a model of flash-strip fermentation process was established, the results from the model were consistent with the experiment values. The theoretically analyses indicate that increasing gas flux and liquid phase recycling ratio can help to enhance productivity and yield of strip-flash fermentation process, and comparison to striping fermentation or flash fermentation, flash-strip fermentation has shown a better productivity. The results has also shown the possibilities of further application and optimization of this process.

Hainan to invest 350 million Yuan in fuel ethanol projects

Hainan Yedao (Group) Co. Ltd. plans to invest 350 million Yuan in construction of a fuel ethanol project. With cooperation of a large state-owned petrochemical enter- prise, this project is planned to produce 100 thousand

Functionalised Poly(Vinyl Alcohol)/Graphene Oxide as Polymer Composite Electrolyte Membranes

Crosslinked poly(vinyl alcohol)(PVA)based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells(DEFC).The membranes were functionalised by means of the addition of graphene oxide(GO)and sulfonated graphene oxide(SGO)and crosslinked with sulfosuccinic acid(SSA).The chemical structure was corroborated and suitable thermal properties were found.Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes,a significant reduction of the ethanol solution swelling and crossover was encountered,more relevant for those functionalised with SGO.In general,the composite membranes were stable under simulated service conditions.The addition of GO and SGO particles permitted to buffer the loss and almost retain similar proton conductivity than prior to immersion.These membranes are alternative polyelectrolytes,which overcome current concerns of actual commercial membranes such as the high cost or the crossover phenomenon.

Synthesis of palladium-rare earth alloy as a high-performance bifunctional catalyst for direct ethanol fuel cells

Direct ethanol fuel cells (DEFCs) have drawn attention for their simplicity, rapid start-up, high power density and environmental friendliness. Despite these advantages, the widespread application of DEFCs faces challenges, primarily due to the inadequate performance of anode and cathode catalysts. Pd-based materials have shown exceptional catalytic activity for both the ethanol oxidation reaction (EOR) and the oxygen reduction reaction (ORR). Alloying noble metals with rare earth elements has emerged as an effective strategy to further enhance the catalytic activity by modulating the electronic structure. In this study, we synthesized a series of palladium-rare earth (Pd3RE) alloys supported on carbon to serve as bifunctional catalysts that efficiently promote both ORR and EOR. Compared to Pd/C, the Pd3Tb/C catalyst exhibits 3.1-fold and 1.8-fold enhancement in activity for ORR and EOR, respectively. The charge transfer in the Pd3Tb/C results in an electron-rich Pd component, thereby weakening the binding energy with oxygen species and facilitating the two reactions.

Carbon Balance of Cassava-based Ethanol Fuel in China

Considering energy security and greenhouse gas emission, many governments are developing bio-liquid fuel industries. The Chinese Government advocates the development of a fuel ethanol industry with non-food crops such as cassava. However, scientists debate the carbon emission of these bio-liquid fuels. The focuses are the influence of soil carbon pool destruction and by-product utilization. This study built a carbon balance analysis model, and assessed carbon emission of cassava fuel ethanol across its life cycle. The results show that the carbon emission of cassava fuel ethanol per kilogram in its life cycle was 0.457 kg under new technical conditions and 0.647 kg under old technical conditions. Carbon emission mainly came from the use of nitrogen fertilizer （9% of total emissions）, the destruction of the soil carbon pool （29%） and fossil energy inputs （50%）. Taking gasoline as a reference, the carbon emission of cassava fuel ethanol was 90% of that of gasoline. This percentage would drop to 64% if soil carbon pool destruction was avoided. Therefore, in order to promote the development of cassava fuel ethanol in China, farms should apply fertilizer properly, grow cassava on marginal land, and not alter land use patterns of woodland, grassland and other environments. In addition, we should exploit efficient fuel ethanol conversion technologies and strengthen the use of by-products.

Surface composition-tunable octahedral PtCu nanoalloys advance the electrocatalytic performance on methanol and ethanol oxidation

The synthesis of surface composition-tunable Pt-based octahedral nanoalloys is key to unravel the structureproperty relationship in fuel cells. Herein, we report a facile route to prepare composition-tunable Pt Cu octahedral nanoalloys by using halogen ions(Br-or/and I-) as composition modulators. Among these Pt Cu octahedral nanoalloys,Pt59 Cu41 octahedron exhibits the highest catalytic activity and durability in alkaline solution. The specific activity/mass activity of Pt59 Cu41 octahedron is 20.25 m A cm^-2/3.24 A mg^-1 Pt,which is 6.64/5.3 times higher than commercial Pt black in 0.5 mol L^-1 CH3 OH, respectively. In the case of using ethanol(0.5 mol L^-1) as fuel source, Pt59 Cu41 octahedron shows much better catalytic activity, that is 34.84 m A cm^-2/5.58 A mg^-1 Pt for specific activity/mass activity, which is 9.16/7.34 times higher than commercial Pt black, respectively. In situ Fourier transform infrared spectroscopy is employed to detect the intermediate species and products for methanol/ethanol oxidation reaction and a plausible mechanism is proposed to explain the improved activity and durability of Pt59 Cu41 octahedron toward methanol/ethanol oxidation in alkaline medium.

Nitrification characteristics of nitrobacteria immobilized in waterborne polyurethane in wastewater of corn-based ethanol fuel production

A technology to achieve stable and high ammonia nitrogen removal rates for corn distillery wastewater （ethanol fuel production） treatment has been designed.The characteristics of nitrifying bacteria entrapped in a waterborne polyurethane （WPU） gel carrier were evaluated after acclimation.In the acclimation period,nitrification rates of WPU-immobilized nitrobacteria were monitored and polymerase chain reaction （PCR） was also carried out to investigate the change in ammonium-oxidizing bacteria.The results showed that the pellet nitrification rates increased from 21 to 228 mg-N/（L-pellet·hr） and the quantity of the ammonia oxidation bacteria increased substantially during the acclimation.A continuous ammonia removal experiment with the anaerobic pond effluent of a distillery wastewater system was conducted with immobilized nitrifying bacteria for 30 days using an 80 L airlift reactor with pellets at a fill ratio of 15% （V/V）.Under the conditions of 75 mg/L influent ammonia,hydraulic retention time （HRT） of 3.7-5.6 hr,and dissolved oxygen （DO） of 4 mg/L,the effluent ammonia concentration was lower than 10 mg/L and the ammonia removal efficiency was 90%.While the highest ammonia removal rate,162 mg-N/（L-pellet·hr）,was observed when the HRT was 1.3 hr.

Highly stable Pt_(3)Ni ultralong nanowires tailored with trace Mo for the ethanol oxidation

Pt_(3)Ni alloy structure is an effective strategy to accelerate ethanol oxidation reaction(EOR),while the stability in acid electrolyte is the fatal weakness and the current density still needs to be enhanced.Herein,ultralong Pt_(3)Ni nanowires tailored by trace Mo(Mo/Pt_(3)Ni NWs)were successfully synthesized by surfactant free method.The specific activity of the optimized catalyst was 2.66 mA·cm^(-2),which is approximately 2.16 and 4.6-fold that of Pt_(3)Ni NWs and commercial Pt/C catalyst,respectively.Most importantly,the Mo/Pt_(3)Ni NWs catalyst showed negligible structure degradation after 3,000 cycles(42 h)of durability test in 0.1 M HClO4 and 0.5 M ethanol,as compared to severe structural collapse and Ni dissolution for the pure Pt_(3)Ni NWs.The density functional theory(DFT)calculation also confirmed that both the surface and subsurface Mo atom could form Pt-Mo and Ni-Mo bonds with Pt and Ni,which were stronger than Pt-Ni bonds,to pin the Ni atoms in the unstable position and suppress the dissolution of surface Ni.The findings of this study indicate a promising pathway for the design and engineering of durable alloy nanocatalysts for direct ethanol fuel cell applications.

Hierarchical TiO_2/ZnO Nanostructure as Novel Non-precious Electrocatalyst for Ethanol Electrooxidation

Metal oxides have a higher chemical stability in comparison to metals,so they can be utilized as electrocatalysts if the activity could be enhanced.Besides the composition,the morphology of the nanostructures has a considerable impact on the electrocatalytic activity.In this work,zinc oxide nano branches-attached titanium dioxide nanofibers were investigated as an economic and stable catalyst for ethanol electrooxidation in the alkaline media.The introduced material has been synthesized by electrospinning process followed by hydrothermal technique.Briefly,electrospinning of colloidal solution consisting of titanium isopropoxide,poly（vinyl acetate） and zinc nanoparticles was performed to produce nanofibers embedding solid nanoparticles.In order to produce TiO2nanofibers containing ZnO nanoparticles,the obtained electrospun nanofiber mats were calcined in air at 600 °C.The formed ZnO nanoparticles were exploited as seeds to outgrow ZnO branches around the TiO2nanofibers using the hydrothermal technique at sub-critical water conditions in the presence of zinc nitrate and bis-hexamethylene triamine.The morphology of the final product,as well as the electrochemical measurements indicated that zinc nanoparticles content in the original electrospun nanofibers has a significant influence on the electrocatalytic activity as the best performance was observed with the nanofibers synthesized from electrospun solution containing 0.1 g Zn,and the corresponding current density was 37 mA/cm2.Overall,this study paves a way to titanium dioxide to be exploited to synthesize effective and stable metal oxide-based electrocatalysts.

Platinum-based ternary catalysts for the electrooxidation of ethanol

Direct ethanol fuel cell(DEFC)as a promising device for converting chemical energy to electricity has been paid ever-increasing attention.However,the slow kinetics of ethanol electrooxidation at an anode hinders the application of DEFCs.Although Pt is the best catalyst among all the pure metal catalysts,it still has a relatively poor ability to break the Csingle bondC bond,is deactivated by the accumulated CO_(ad) intermediates,and undergoes unwanted desired structure change over long-term operation.In recent years,the addition of other metals to form binary,ternary,and quaternary catalysts have significantly improved electroactivity and stability.Ternary catalysts can have numerous element combinations and complicated architectures and,therefore,have been the subject of considerable research.In this review,most of the reported ternary catalysts will be summarized and categorized according to their structure while discussing the essence of the role of each component.

High stability three-dimensional porous PtSn nano-catalyst for ethanol electro-oxidation reaction

In addition to the theoretical research,direct ethanol fuel cells have great potential in practical applications.The performance of direct ethanol fuel cells largely depends on the electrocatalysts.Ptbased electrocatalysts have been promising candidates for advancing direct ethanol fuel cells for its high catalytic activity and great durability.Here,a PtSn catalyst with unique three-dimensional porous nanostructure has been designed and synthesized via a two-step liquid phase reduction reaction.Sn formed a self-supporting framework in PtSn alloy particles(~3.5 nm).In ethanol electro-oxidation reaction,the PtSn catalyst exhibited high mass activity and excellent recycling time compared with that of Pt/C.After the morphology characterization before and after potential cycling,the PtSn alloy-based nano-catalyst showed good stability.The PtSn catalysts effectively avoid structural instability due to the external carriers,and prolong the leaching time of Sn.In addition,the introduction of a certain amount of Sn can also solve the poisoning phenomenon of active sites on Pt surface.The design strategy of porous alloy nano-catalyst sheds light on its applications in direct ethanol fuel cells.

Self-supporting trimetallic PtAuBi aerogels as electrocatalyst for ethanol oxidation reaction

The creation of anodic ethanol oxidation reaction catalysts with superior all-around performance for direct ethanol fuel cells(DEFCs)has continued to attract the attention of researchers.An ultrathin trimetallic PtAuBi aerogel with branching,rough-surfaced 1D nanowires that self-assemble into a 3D porous network structure has been created in this study.It has a mass activity(MA)of 8045 mA mgPt^(-1)in an alkaline medium,which is 7.56 times greater than that of commercial Pt/C(1064 mA mgPt^(-1)).Notably,the catalytic activity and resistance to CO poisoning of PtAuBi aerogels are improved by the addition of an efficient"active additive"Au.The results analysis reveals that the increased performance of PtAuBi aerogel is mostly attributable to the integrated function of the 3D porous network structure,the downward shift of the Pt d-band center,and the synergistic effect of the"Pt-Bi"and/or"Pt-Au"dual active sites.

Combustion characteristics of nanofluid fuels in a half-opening slot tube

Combustion characteristics of nanofluid fuels containing aluminum nanoparticles were investigated in half-opening slot tubes from the fundamental view. The effects of particle loading rates(0.25% and 2.5% by weight), type of base fuels(ethanol and butanol),and fuel flow rates(0.2, 0.6, and 1 mL/min) were studied in details. The combustion characteristics of the nanofluid fuels and pure based fuels were also examined to provide a comparison. Flame was unstable with reignition, stable state, nearly extinguishment repeatedly at low flow rate. At medium flow rate, flame height was increased and flame tended to be stable. At high flow rate,flame became unstable and was disturbed by the droplet forming and dripping significantly. Al atoms inside the oxide layer should be melted before the particles combustion, while Al oxide layer should be melted before the particles aggregates combustion. The effects of particles on the combustion characteristics, especially on the evaporation rate of base fuel, were discussed. The reasons for various combustion phenomena of nanofluid fuels were given, which can provide the useful guidance for the experimental research and practical applications of nanofluid fuels.