Microfluidic synthesis of thiourea modified chitosan microsphere of high specific surface area for heavy metal wastewater treatment

An improved biosorbent of thiourea modified chitosan microsphere（TMCM） with high specific surface,favorable mechanical strength and excellent adsorption performance had been synthesized via microfluidic technology. Polyethylene glycol was used as a significant component added in aqueous solution of chitosan to produce such microspheres through droplets forming, chemical crosslinking and pores creating. For the improvement of adsorption capacity, thiourea was considered as an excellent choice in increasing amino functional group by graft modification. The SEM, FTIR and EDS were employed to detect distinct features of TMCM. Copper（Ⅱ） was used to test the adsorption performance of TMCM. The experimental results indicated that TMCM exhibited higher adsorption capacity（q_e= 60.6 mg g_（-1）） and faster adsorption rate than that non-modified chitosan microsphere（NMCM）.The adsorption kinetic was described well by the pseudo-second order kinetic model, which suggested that chemical adsorption along with electrons transferring was dominant in adsorption process.

Homogeneous Zr and Ti co-doped SBA-15 with high specific surface area:preparation,characterization and application

A facile synthesis procedure is proposed to prepare homogeneous Zr and Ti co-doped SBA-15(Zr-Ti-SBA-15)with high specific surface area of 876.0m2 g−1.Based on“masking mechanism”from tanning,lactic acid was used as masking agent to obtain the uniform distribution of Zr and Ti species in the SBA-15 framework.The obtained materials were characterized by powder X-ray diffraction(XRD),nitrogen adsorption-desorption isotherms,scanning electron microscope(SEM),transmission electron microscope(TEM)and X-ray photoelectron(XPS).The results reveal that in mesoporous materials,the presence of lactic acid gives rise to the uniform distribution of Zr and Ti species.The adsorption equilibrium and kinetic studies of Zr-Ti-SBA-15 materials show that the adsorption process conforms to the Langmuir isotherm and pseudo-second-order kinetic model,respectively.Regenerational experiments show that the Zr-Ti-SBA-15 displays a significant adsorption ability for methylene blue(MB)(up to 291.6 mg/g),along with good reusability,indicating promising potentials of commercialization.Methodologically,this work provides a wide range of possibilities for further development of SBA-15 based on bimetallic and sewage disposal.

Nitrogen-doped hierarchical few-layered porous carbon for efficient electrochemical energy storage

Large surface area,high conductivity,and rich active site of carbon electrode materials are necessary characteristics for energy storage devices.However,high conductivity and high nitrogen doping of carbon electrode materials are difficult to coordinate.Here,a facile method via the carbonization of nitrogen-containing Schiff base polymer has been developed to prepare high conductivity and high nitrogen-doped hierarchical porous carbon.The organic components with a benzene ring structure in the polymer promote the formation of more sp^(2)-graphitized carbon,which is beneficial for the improvement of electrical conductivity.Nitrogen-doped hierarchical porous carbon calcined at 900℃ under the NH3 atmosphere possesses high nitrogen content of 7.48 at%,a large specific surface area of 1613.2m2/g,and high electrical conductivity of 2.7 S/cm.As electrode materials in an aqueous-based supercapacitor,nitrogen-doped hierarchical porous carbon exhibits superior specific capacitance of 385 F/g at 1 A/g as well as excellent rate performance(242 and 215 F/g at a current density of 100 and 200 A/g,respectively).In addition,the specific capacitance of electrode measured in a two-electrode system is 335 F/g at 1 A/g,and the long-term cycling stability can be achieved with more than 94%initial capacitance after 10000 cycles.The constructed symmetric supercapacitor delivers high energy density and high power density.The outstanding electrochemical performances combined with the novel and scalable synthetic approach make the nitrogen‐doped hierarchical porous carbon potential electrode material for electrochemical devices.

Hierarchical TiO2 Flower-spheres with Large Surface Area and High Scattering Ability： an Excellent Candidate for High Efficiency Dye Sensitized Solar Cells

Hierarchical TiO2 flower-spheres assembled from porous nanosheets-stacked of nanoparticles were synthesized by a simple hydrothermal method with one-step. The as-prepared TiO2 flower-spheres showed a diameter range from 200 nm to 550 nm and a large surface area of 188 m^2/g. A double layer photoanode made of P25 nano- particles and as-prepared TiO2 flower-spheres was fabricated for the dye sensitized solar cells（DSSCs）. The efficient light scattering and dye absorption of the photoanode can be attributed to the top-layer of hierarchical TiO2 flower-spheres. DSSCs based on the double layers photoanode exhibit a higher energy conversion efficiency of 8.11% with a short-circuit photocurrent density of 17.87 mA/cm^2, indicating that there is an increase of 38% in the conversion efficiency compared to those based on electrode P25（5.91%, 14.09 mA/cm^2）.

Defect-rich and highly porous carbon nanosheets derived from Ti_(3)AlC_(2) MAX with good lithium storage properties

Defect-rich,highly porous two-dimensional carbon nanosheets(CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields,because of their unique micromorphology,chemical stability and high specific surface area.Herein,in this work,we report a new solution to synthesize an ultrathin two-dimensional CNS with rich defects and abundant pores via two-step etching the Ti_(3)AlC_(2)with the help of I2and NaOH.The CNS thickness,specific surface area and pore volume could be all tunable by adding the amount of I2.And the highest specific surface area and pore volume of the synthesized 2D CNS can be achieved 1134.4 m^(2)/g and 0.80 cm^(3)/g,with a thickness of only 0.64 nm and a yield of 35.9%.When employed as the anodes for lithium-ion batteries,the synthesized CNS anodes exhibit good cycling and rate capabilities.This work provides a novel and facile strategy for synthesizing highly porous and defective 2D carbon materials with good lithium storage properties.

Two-dimensional porous carbon derived from pollen with enlarged interlayer distance enhanced electrocatalytic oxidation of n-valeraldehyde to octane

Electrocatalytic n-valeraldehyde oxidation reaction was an inexpensive and eco-friendly method to control n-valeraldehyde contamination and produce high value-added octane.However,low-cost and readily available electrocatalysts with high current efficiency were urgently needed.Herein,two-dimensional porous carbon derived from pollen with enlarged interlayer distance was built by alkali activation method,applying in electrocatalytic n-valeraldehyde oxidation reaction.The enlarged interlayer distance was verified by X-ray diffraction(XRD)and high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM).Electrocatalytic experiments consequences showed activated biomass derived carbon possessed a higher electrocatalytic activity and octane selectivity than unactivated catalyst.Systematic tests and in situ infrared experiments demonstrated that enlarged interlayer distance was positively correlated with specific surface area of catalysts,large specific surface area provided abundant absorption sites,facilitated the adsorption for n-valeraldehyde,and further promoted the transformation of n-valeraldehyde to octane.This work also provides a new avenue for creating high-performance electrocatalysts in terms of lattice engineering.

Biomass-derived nitrogen self-doped porous activation carbon as an effective bifunctional electrocatalysts

The strategy of adopting cheap precursors or abundant resources,which can be obtained directly from nature,is a simple and excellent method of introducing accessible research into environmentally friendly development.Moreover,this is also an urgent requirement for the sustainable development of green technology.Herein,we introduce a simplistic and expandable method to prepare metal-free biomassderived nitrogen self-doped porous activation carbon(N-PAC) with large specific surface area(S_(BET)=1300.58 m^(2)/g).Moreover,the manufactural electrocatalysts exhibit prominent oxygen reduction reaction(ORR) performance in all PH values.As compared with the commercial Pt/C catalyst,the N-PAC/800 with a positive onset potential at 10 mA/cm^(2)(0.93 V),half-wave potential(0.87 V),and limiting current(6.34 mA/cm^(2)) bring to light excellent catalytic stability,selectivity,and much-enhanced methanol tolerance.Furthermore,the prepared electrocatalysts possess considerable hydrogen evolution reaction(HER) performance with a less onset potential of 0.218 V(acidic medium) and0.271 V(alkaline medium) respectively,which can show similar catalytic activity across the whole pH range.Such bifunctional electrocatalyst,with excellent electrocatalytic properties,resource-rich,low cost,and environmental-friendly,hold a promising application in energy conversion and reserve.

PVP-assisted preparation of nitrogen doped mesoporous carbon materials for supercapacitors

The rich porous structure,high surface area and surface doping make nitrogen doping mesoporous carbon materials(N-MPC)attractive in various areas,including adsorption separation,electrochemical energy storage,catalysis and other fields.Herein,polyvinylpyrrolidone(PVP)is introduced into the polymerization process of assembly of phenol/formaldehyde(PF)resin by means of hydrogen bonds and electrostatic interaction,which not only leads to the formation of uniform mesopores,but also leads to the increase of specific surface area and nitrogen doping.The amount of PVP and annealing temperature has no obvious effect on morphology,but subsequently has effect on the specific surface area and pore volume.When appropriate PVP dosage and annealing temperature are adopted,the obtained N-MPC shows abundant mesoporous,high surface area and suitable nitrogen doping.As electrode materials in supercapacitor,the N-MPC shows good performance with high capacitance good stability and rate performance,presenting its excellent promising in energy storage.