The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quant...The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quantum dots with superlattice structure(NVP-QDs-SL) for obtaining precise control of the size, distribution and crystallinity. The multifunctional lignocelluloses(LCs) used as a hard carbon source induce heterogeneous nucleation and confined growth of NVP-QDs-SL, leading to the uniform distribution of NVP-QDs-SL in H/S-doped hard carbon ultra-thin nanosheets(HCS). Detailed electrochemical analysis results from sodium-ion batteries of NVP-QDs-SL show that NVP-QDs-SL could trap the electrons inside HCS, significantly enhancing Na ion storage and transfer kinetics. Compared to the common Na3 V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g^-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2(PO4)3(117.6 m A h g^-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A h g-1.Even after cycling at 20 C over 3000 cycles, an ultrahigh coulombic efficiency close to 100% is still obtained,highlighting its excellent long cycling life, remarkable rate performance and energy density.展开更多
Six different environmental samples were applied to enrich microbial consortia for efficient degradation of corn stalk,under the thermophilic and mesophilic conditions.The consortium obtained from anaerobic digested s...Six different environmental samples were applied to enrich microbial consortia for efficient degradation of corn stalk,under the thermophilic and mesophilic conditions.The consortium obtained from anaerobic digested sludge under thermophilic condition(TC-Y)had the highest lignocellulose-degrading activity.The CO_2yield was 246.73 m L/g VS in23 days,meanwhile,the maximum CO_2production rate was 15.48 mL/(CO_2·d),which was28.75%and 52.27%higher than that under mesophilic condition,respectively.The peak value of cellulase activity reached 0.105 U/mL,which was at least 34.61%higher than the other groups.In addition,49.5%of corn stalk was degraded in 20 days,moreover,the degradation ratio of cellulose,hemicellulose and lignin can reach 52.76%,62.45%and42.23%,respectively.Microbial consortium structure analysis indicated that the TC-Y contained the phylum of Gemmatimonadetes,Acidobacteria,Chloroflexi,Planctomycetes,Firmicutes,and Proteobacteria.Furthermore,the Pseudoxanthomonas belonging to GammaProteobacteria might be the key bacterial group for the lignocellulose degradation.These results indicated the capability of degrading un-pretreated corn stalk and the potential for further investigation and application of TC-Y.展开更多
Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeri...Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeric substances by extracellular enzymes, such as cellulases, hemicellulases and laccases, is preferred to chemical depolymerisation to avoid the production of toxic by-products and waste that are expensive to treat. The monosaccharides released through enzymatic hydrolysis can subsequently be microbially converted to commercial commodities, such as bio-ethanol (fuel extender) or microbial protein as feed supplements. The individual depolymerisering enzymes used, such as cellulases, xylanases and laccases, also have industrial application in (i) biobleaching in the paper and pulp industry, (ii) improvement of animal feed (poultry and ruminants) digestibility in feed industries, and (iii) dough rheology and bread volume in the baking process, and beer viscosity and filtration velocity during brewing. The cloning of the genes, coding for several xylan degrading enzymes, and their expression in Baker’s yeast (Saccharomyces cerevisiae) and filamentous fungi (Aspergillus species) opened the possibility to study the pure enzymes, without contaminating activity. Trichoderma reesei produces several of these enzymes and detailed information on their specificity, synergies and structure/activity relationships is known. An overview will be presented.展开更多
基金supported financially by the National Natural Science Foundation of China (Nos. 51672139, 51472127 and 51272144)the Projects Supported by the Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education (No. KF2016-01)
文摘The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quantum dots with superlattice structure(NVP-QDs-SL) for obtaining precise control of the size, distribution and crystallinity. The multifunctional lignocelluloses(LCs) used as a hard carbon source induce heterogeneous nucleation and confined growth of NVP-QDs-SL, leading to the uniform distribution of NVP-QDs-SL in H/S-doped hard carbon ultra-thin nanosheets(HCS). Detailed electrochemical analysis results from sodium-ion batteries of NVP-QDs-SL show that NVP-QDs-SL could trap the electrons inside HCS, significantly enhancing Na ion storage and transfer kinetics. Compared to the common Na3 V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g^-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2(PO4)3(117.6 m A h g^-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A h g-1.Even after cycling at 20 C over 3000 cycles, an ultrahigh coulombic efficiency close to 100% is still obtained,highlighting its excellent long cycling life, remarkable rate performance and energy density.
基金supported by the National Natural Science Foundation of China (No. 41773102)the Key Research & Development Project of Shandong (No. 2017GSF217007)the Key Technological Innovation Project of Shandong (No. 2017CXGC0305)
文摘Six different environmental samples were applied to enrich microbial consortia for efficient degradation of corn stalk,under the thermophilic and mesophilic conditions.The consortium obtained from anaerobic digested sludge under thermophilic condition(TC-Y)had the highest lignocellulose-degrading activity.The CO_2yield was 246.73 m L/g VS in23 days,meanwhile,the maximum CO_2production rate was 15.48 mL/(CO_2·d),which was28.75%and 52.27%higher than that under mesophilic condition,respectively.The peak value of cellulase activity reached 0.105 U/mL,which was at least 34.61%higher than the other groups.In addition,49.5%of corn stalk was degraded in 20 days,moreover,the degradation ratio of cellulose,hemicellulose and lignin can reach 52.76%,62.45%and42.23%,respectively.Microbial consortium structure analysis indicated that the TC-Y contained the phylum of Gemmatimonadetes,Acidobacteria,Chloroflexi,Planctomycetes,Firmicutes,and Proteobacteria.Furthermore,the Pseudoxanthomonas belonging to GammaProteobacteria might be the key bacterial group for the lignocellulose degradation.These results indicated the capability of degrading un-pretreated corn stalk and the potential for further investigation and application of TC-Y.
文摘Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeric substances by extracellular enzymes, such as cellulases, hemicellulases and laccases, is preferred to chemical depolymerisation to avoid the production of toxic by-products and waste that are expensive to treat. The monosaccharides released through enzymatic hydrolysis can subsequently be microbially converted to commercial commodities, such as bio-ethanol (fuel extender) or microbial protein as feed supplements. The individual depolymerisering enzymes used, such as cellulases, xylanases and laccases, also have industrial application in (i) biobleaching in the paper and pulp industry, (ii) improvement of animal feed (poultry and ruminants) digestibility in feed industries, and (iii) dough rheology and bread volume in the baking process, and beer viscosity and filtration velocity during brewing. The cloning of the genes, coding for several xylan degrading enzymes, and their expression in Baker’s yeast (Saccharomyces cerevisiae) and filamentous fungi (Aspergillus species) opened the possibility to study the pure enzymes, without contaminating activity. Trichoderma reesei produces several of these enzymes and detailed information on their specificity, synergies and structure/activity relationships is known. An overview will be presented.
