Preparation And Application Of Liquefied Larch Based Carbons With Tunable Morphology And Porous Structure

Porous carbon materials with tunable morphology and porous structure have attracted considerable attention in the fields of energy storage and converse,high catalysis,nano-devices and controlled drug delivery.However,porous carbon materials are mainly prepared from fossile fuel and polymers,which have a limit in the industrial application for porous carbon materials.Woody biomass resources have huge reserves and can recycle naturally,which are commonly used to prepare porous carbon.However,woody biomass is a kind of natural polymer containing cellulose,hemicellulose and lignin with many oxygen speices,which is hard to dissolve and melt without liquefied process.Thus direct carbonization of woody biomass is a typical solid carbonization,which keeps the original biological structure and difficult to get the excellent microcrystal and produce the ordered pore structure.Therefore,there is a huge technical obstacle to prepare carbon material with controlled structure from woody biomass resources through traditional methods.In order to prepare carbon materials from woody biomass,a dissolution-controlled polymerization-carbonization method is used to prepare porous carbon.Larch is liquefied by phenol,and then formed mesophase through resin reaction and block copolymer with tunable morphology and porous structure.After carbonization,a series of carbon materials with controlled morphology and porous structure are obtained.The effect of the cellulose and lignin components in larch on pore structure of carbon materials is widely investigated.The results show that larch liquefied products have many phenolic compound and lignin liquefied products are easy to crosslink with block copolymers.Also the effect of type and amount of soft template is studied,and doping with metal ions to modify the porous structure of carbon materials,which can improve the permeability of carbon membrane and keep high selectivtity.Carbon spheres are synthesized from liquefied larch sawdust solution via the ultrasonic spray pyrolysis method.The morphology and porosity of the carbon spheres are investigated by changing the concentration of the liquefied larch sawdust solution and carbonization temperature.The ordered porous structures of carbon sphere are preparation by adding the soft template F127.Foam-based conical nano nickel is prepared by electroless nickel plating on liquefied larch based foam,and displays the outstanding glucose sensing represented performance.Futhermore,carbon nanowires are fabricated through nanocasting technology using ion-track etched polymers as templates and phenolic resin as carbon sources.Additioanlly,different alloy metals are prepared using PET as templates via the etching and chemical deposition,and the electrochemical catalytic performance are investigated.Detailed discuss as follows:Carbon membranes with different porous structures are prepared through self-assemble and carbonziation using liquefied larch,phenol,formaldehyde,larch cellulose and lignin as resources and ptriblock copolymer F127 as soft template.The results indicate that lignin liquefied products are easy to crosslink with block copolymers improving more pores and larch liquefied products have many phenolic compounds and afford feasible to prepare carbon materails with tunable morpholgoy and porous structure.Furthermore,carbon membranes are prepared using natural renewable larch sawdust as starting material and F127 and P23 as soft template via liquefaction,resinification,self-assembly and carbonization processes.The porous structure of carbon membranes prepared with F127 at 700 ℃ have two-dimensional hexagonal porous structure,and the surface area and pore volume are 469 m2/g and 0.250 cm3/g respectively,and the ratio of micropore reached 87%.Similarly,the porous structure of carbon membranes prepared with P123 at 700 ℃ have an ordered spherical porous structure.The surface area is 393 m2/g,the pore volume is 0.237 cm3/g,and the Smicro/SBET is 77%.Furthermore,we selected the mixture of F127 and P23 as soft template to tailor the pore structure of carbon membranes,and the effect of EO/PO ratio on the formation of porosity is investigated.When EO/PO ratio is 1,the strong interaction of EO and PO can result in the formation more pores with high surface area(637 m2/g).The porosity gradually becomes ordered due to the low interaction between EO and PO units.With the decreas of EO/PO ratio,hydrophobic groups led to a low interfacial curvature,and the sphereical hexagonal porous structures are formed.With the increase of EO/PO ratio,hydrophilic groups led to an enhanced interfacial curvature,and the 2D hexagonal porous structures are formed.Additionally,the carbon materials are used to test the capative performance,indicating the high capacitance.The carbon materials with two-dimensional hexagonal porous structure has the superir performance,and the specific capacitance was 141 F/g and retained 98%of the initial capacitance after 2000 cycles,indicating the excellent rate performance.The gas separation tests exhibit that the carbon membranes prepared with higher temperature has an enhanced selectivity but low permeability.Based on the decrease of gas permeability of carbon membranes,Ni(NO3)2 is used to tune the pore structure.The addition of Ni(NO3)2 not only maintain the ordered porous structure and high selectivity also enlarge the pore size to improve the permeability of carbon membranes.Hollow carbon spheres with flower-like morphology are synthesized from liquefied larch sawdust dilution solution via the ultrasonic spray pyrolysis method.The morphology and structure of the carbon spheres can be controlled by the concentration of the liquefied larch sawdust solution and carbonization temperature.The results indicate that the size of carbon spheres enlarge when the concentration of liquefied larch solution increases from 5%to 15%.The carbonization gradually completes with the increase of the carbonization temperature.The uniform spheres with a narrow size distribution of 600-900 nm can be obtained from 5%liquefied larch solution at 800 ℃.Meanwhile,the carbon spheres exhibit a high surface area(413 m2/g),and the pore size distribution is in the range of 1.8-3 nm.The carbon materials have a high methyl orange adsorption capacity(140 mg/g).Additionally,ordered hollow flower-like carbon spheres are prepared using F127 as a soft template at the optimal conditions for the synthesis of liquefied larch carbon sphere,which have a high specific surface area of 502 m2/g and pore volume of 0.40 cm3/g.The carbon spheres show a moderate specific capacitance of 141 F/g,indicating the good capacitive performance and electrical conductivity.Furthermore,hollow carbon spheres with smooth morphology and uniform size are synthesized from liquefied larch resin dilution solution via the ultrasonic spray pyrolysis method.The carbon spheres exhibit a high surface area(465 m2/g),and the pore size distribution is in the range of 1.8-8 nm.The carbon mateirals have a high specific capacitance of 162 F/g,which exhibit good capacitive performance and electrical conductivity.Furthermore,ordered hollow carbon spheres are prepared using F127 as a soft template under the optimal conditions for the syntheisis of liquefied larch resin based carbon spheres.The carbon spheres possess a moderate surface area of 520 m2/g and pore volume of 0.42 cm3/g.Compared with the hollow carbon spheres prepared from liquefied larch,the carbon spheres prepared with liquefied resin are more stable,and have larger surface area.The sample exhibits high specific capacitance of 190 F/g,indicating good capacitive performance and electrical conductivity.Carbon foam has been prepared from larch for the electroless depositon.Liquefied larch is polymerized with formaldehyde to obtain thermosetting resin with proper viscosity under the control of polyethylene glycol(PEG).The resulted composites are mixed with polysorbate 80 with strong stir,and thermosetting carbon foam with stable framework is synthesized by foaming and curing in the aid of sulfuric acid.The foam slice is used as a substrate for electroless nickel plating,and the morphology of materials is controlled by sensitization and activation conditions.Results indicate that conical structure nickel is vertically formed on the surface of the foam with 40-50° slope in very low concentrations of sensitization and activation solution,and height is ca.100-250 nm,which displays the outstanding glucose sensing performance.The sensitivity of materials to glucose is up to 8.1 mA/mM/cm2,and the limit of detect(LOD)reaches 60 nM,which shows better performance than many noble metal-based catalysts.Carbon nanowires with superstructures are synthesized using soft method and nanocasting process,in which ion-track etched polymers are used as templates.In the syntheisis process,polycarbonate with multiple inclined arrays is used as template,which is etched by NaOH,folowing by the fill of resins and crosslinking at moderate temperature.Finally,the template is removed at high temprature carbonization to obtain interconnected network carbon nanowires.The diameter of the carbon nanowires is up to 300 nm,and the length reaches 10 μm.This interconnected network morphology can improve the physical and chemial performance of carbon nanowires.