Integration of morphology and electronic structure modulation on cobalt phosphide nanosheets to boost photocatalytic hydrogen evolution from ammonia borane hydrolysis

The controllable and safe hydrogen storage technologies are widely recognized as the main bottleneck for the accomplishment of sustainable hydrogen energy.Ammonia borane(AB)has regarded as a competitive candidate for chemical hydrogen storage.However,developing efficient yet high-performance catalysts towards hydrogen evolution from AB hydrolysis remains an enormous challenge.Herein,cobalt phosphide nanosheets are synthesized by a facile salt-assisted along with low-temperature phosphidation strategy for simultaneously modulating its morphology and electronic structure,and function as hydrogen evolution photocatalysts.Impressively,the Co_(2)P nanosheets display extraordinary performance with a record high turnover frequency of 44.9 min^(-1),outperforming most of the noble-metal-free catalysts reported to date.This remarkable performance is attributed to its desired nanosheets structure,featuring with high specific surface area,abundant exposed active sites,and short charge diffusion paths.Our findings provide a novel strategy for regulating metal phosphides with desired phase structure and morphology for energy-related applications and beyond.

An efficient and mild recycling of waste melamine formaldehyde foams by alkaline hydrolysis

Melamine formaldehyde foam(MFF)generates many poisonous chemicals through the traditional recycling methods for organic resin wastes.Herein,a high MFF degradation ratio of ca.97 wt.%was achieved under the mild conditions(160℃)in a NaOH–H2O system with ammelide and ammeline as the main degradation products.The alkaline solvent had an obvious corrosion effect for MFF,as indicated by scanning electron microscopy(SEM).The reaction process and products distribution were studied by Fourier-transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and ^(13)C nuclear magnetic resonance(NMR).Besides,the MFF degradation products that have the similar chemical structures and bonding performances to those of melamine can be directly used as the raw material for synthesis of melamine urea-formaldehyde resins(MUFs).Moreover,the degradation system demonstrated here showed the high degradation efficiency after reusing for 7 times.The degradation process generated few harmful pollutants and no pre-or post-treatments were required,which proves its feasibility in the safe removal or recovery of waste MFF.

In situ formed Mg(BH_(4))_(2) for improving hydrolysis properties of MgH_(2)

The hydrolysis of MgH_(2) delivers high hydrogen capacity(15.2 wt%),which is very attractive for real-time hydrogen supply.However,the formation of a surface passivation Mg(OH)_(2) layer and the large excess of H_(2)O required to ensure complete hydrolysis are two key challenges for the MgH_(2) hydrolysis systems.Now,a low-cost method is reported to synthesize MgH_(2)@Mg(BH_(4))_(2) composite via ball-milling MgH_(2) with cheap and widely available B_(2)O_(3)(or B(OH)_(3)).By adding small amounts of B_(2)O_(3),the in-situ formed Mg(BH_(4))_(2) could significantly promote the hydrolysis of MgH_(2).In particular,the MgH_(2)–10 wt%B_(2)O_(3) composite releases 1330.7 mL·g^(−1) H_(2)(close to 80%theoretical hydrogen generation H_(2))in H_(2)O and 1520.4 mL·g^(−1) H_(2)(about 95%)in 0.5 M MgCl_(2) in 60 min at 26℃ with hydrolysis rate of 736.9 mL·g^(−1)·min^(−1) and 960.9 mL·g^(−1)·min^(−1) H_(2) during the first minute of the hydrolysis,respectively.In addition,the MgCl_(2) solution allows repeated use by filtering and exhibits high cycle stability(20 cycles),therefore leading to much reduced capacity loss caused by the excess H_(2)O.We show that by introducing B_(2)O_(3) and recycling the 0.5 M MgCl_(2) solution,the system hydrogen capacity can approach 5.9 wt%,providing a promising hydrogen generation scheme to supply hydrogen to the fuel cells.

Enzymatic hydrolysis of silkworm pupa and its allergenicity evaluation by animal model with different immunization routes

Silkworm pupa is a nourishing food with high nutritional value,but its consumption has been greatly limited given its allergenicity.Enzyme hydrolytic technique is recognized as an effective method to reduce the allergenicity of protein.In this study,we aimed to investigate the effect of enzymolysis on the allergenicity of silkworm pupa.Crude silkworm pupa protein was extracted through alkali extraction and acid precipitation,which included 5 proteins with the molecular weights ranging from 34 kDa to 76 kDa,and silkworm pupa were then hydrolyzed by alkaline protease.The allergenicity of silkworm pupa protein and its enzymatic hydrolysates was evaluated by establishing BALB/c mice model,and the mice were immunized via intragastric gavage and intraperitoneal injection,respectively.The results indicated that the intraperitoneal inj ection immunization route induced more by detecting with antibodies,histamine and Th2-related cytokines.Moreover,mice treated with silkworm pupa protein peptide displayed no obvious allergic symptoms,indicating that enzyme hydrolytic technique could significantly reduce the allergenicity of silkworm pupa.

Oxygen vacancy defects engineering on Cu-doped Co_(3)O_(4) for promoting effective COS hydrolysis

The activation of H_(2)O is a key step of the COS hydrolysis,which may be tuned by oxygen vacancy defects in the catalysts.Herein,we have introduced Cu into Co_(3)O_(4) to regulate the oxygen vacancy defect content of the catalysts.In situ DRIFTS and XPS spectra reveal that COS and H_(2)O are adsorbed and activated by oxygen vacancy.The 10 at%Cu doped Co_(3)O_(4) sample(10Cu-Co_(3)O_(4))exhibits the optimal activity,100%of COS conversion at 70℃.The improved oxygen vacancies of CueCo_(3)O_(4) accelerate the activation of H_(2)O to form active -OH.COS binds with hydroxyl to form the intermediate HSCO^(-)_(2),and then the activated-OH on the oxygen vacancy reacts with HSCO^(-)_(2) to form HCO^(-)_(3).Meanwhile,the catalyst exhibits high catalytic stability because copper species(Cu+/Cu^(2+))redox cycle mitigate the sulfation of Co_(3)O_(4)(Co^(2+)/Co^(3+)).Our work offers a promising approach for the rational design of cobalt-related catalysts in the highly efficient hydrolysis COS process.

Structural and antioxidative properties of royal jelly protein by partial enzymatic hydrolysis

The objective of this study was to investigate the structural and antioxidative properties of royal jelly protein(RJP)at different degrees of hydrolysis(DH)by partial enzymatic hydrolysis. RJP was hydrolyzed by alcalase for 0 min, 15 min, 1 h, 5 h and 8 h to obtain hydrolysates at DH of 5.34%, 11.65%, 15.19%, 21.38% and 23.91%, respectively. With the increased DH, the RJP hydrolysates showed elevated antioxidative activities. The molecular weight of RJP hydrolysates was significantly decreased but their primary backbone kept unchanged. Analysis of circular dichroism spectra revealed that the enzymolysis reduced the content of α-helix but increased the contents of β-sheet, β-turn and random coil. Meanwhile, the surface hydrophobicity and fluorescence intensity of RJP hydrolysates were decreased and a red shift occurred. As the enzymolysis continued, the surface morphology of RJP was gradually changed from a sheet-like structure into microparticles. Changes in antioxidative activities and structures generally followed a DH-dependent manner, however these changes became insignificant for samples at DH beyond 20%. Taking into consideration of both effectiveness and productivity, the optimum enzymatic duration was determined at 5 h.

Effect of acid-associated mechanical pretreatment on the hydrolysis behavior of pine sawdust in subcritical water

The effects of sulfuric acid-associated mechanical pretreatment on the hydrolysis behavior of pine sawdust were investigated in this study.Sulfuric acid could act as an acidic catalyst to depolymerize holocellulose through cleavage of the glycosidic bonds,the dissociation energies of which were supplied by the impact of a ball on pine sawdust,during milling.The destruction of glycosidic and hydrogen bonds in pine sawdust resulted in a decrease of crystallinity and an increase of water solubility.The sulfuric acid could promote the hydrolysis of holocellulose and its hydrolysis products.It also destroyed the chemical linkages between holocellulose and lignin during ball milling.The cleavage of chemical linkages with holocellulose made lignin more difficult to hydrolyze in subcritical water,and higher activation energy was needed to hydrolyze pretreated pine sawdust at higher reaction temperatures.It also led to the formation of glucose char and aromatic-linked polymer char from the hydrolysis products of holocellulose.

Hydrogel-based catalysts for hydrogen generation by the hydrolysis of B–H compounds under external physical fields

Hydrogen is a popular clean high-energy-density fuel.However,its utilization is limited by the challenges toward low-cost hydrogen production and safe hydrogen storage.Fortunately,these issues can be addressed using promising hydrogen storage materials such as B–H compounds.Hydrogen stored in B–H compounds can be released by hydrolysis at room temperature,which requires catalysts to increase the rate of the reaction.Recently,several effective approaches have been developed for hydrogen generation by catalyzing the hydrolysis of B–H compounds.This review summarizes the existing research on the use of nanoparticles loaded on hydrogels as catalysts for the hydrolysis of B–H compounds.First,the factors affecting the hydrolysis rate,such as temperature,p H,reactant concentration,and type of nano particles,were investigated.Further,the preparation methods(in situ reduction,one-pot method,template adsorption,etc.)for the hydrogel catalysts and the types of loaded catalysts were determined.Additionally,the hydrogel catalysts that can respond to magnetic fields,ultrasound fields,optical fields,and other physical fields are introduced.Finally,the issues and future developments of hydrogel-based catalysts are discussed.This review can inspire deeper investigations and provide guidance for the study of hydrogel catalysts in the field of hydrogen production via hydrolysis.

Effects of Potassium Ferrate and Low-Temperature Thermal Hydrolysis Co-Pretreatment on the Hydrolysis and Anaerobic Digestion Process of Waste Activated Sludge

This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobic digestion process.The analytical investigations showed that co-pretreatment significantly facilitated the hydrolysis process of the sludge and contributed to the accumulation of short-chain fatty acids(SCFAs).The pretreatment conditions under the optimal leaching of organic matter from sludge were hydrothermal temperature of 75℃,hydrothermal treatment time of 12 h,and PF dosage of 0.25 g g^(−1)TSS(total suspended solids),according to the results of orthogonal experiments.By pretreatment under proper conditions,the removal rate of soluble chemical oxygen demand(SCOD)achieved 71.8%at the end of fermentation and the removal rate of total phosphorus(TP)was 69.1%.The maximum yield of SCFAs was 750.3 mg L^(−1),7.45 times greater than that of the blank group.Based on the analysis of the anaerobic digestion mechanism,it was indicated that the co-pretreatment could destroy the floc structure on the sludge surface and improve organic matter dissolving,resulting in more soluble organic substances for the acidification process.Furthermore,microbial community research revealed that the main cause of enhanced SCFAs generation was an increase in acidogenic bacteria and a reduction of methanogenic bacteria.

Preliminary Study on the Treatment Efficiency of Pasteurized Lime Thermal Alkaline Hydrolysis for Excess Activated Sludge and Reduction of Tetracycline Resistance Genes

Thermal alkaline hydrolysis is a common pretreatment method for the utilization of excess activated sludge(EAS).Owing to strict environment laws and need for better energy utilization,new methods were developed in this study to improve the efficiency of pretreatment method.Direct thermal hydrolysis(TH),pasteurized thermal hydrolysis(PTH),and alkaline pasteurized thermal hydrolysis(PTH+CaO and PTH+NaOH)methods were used to treat EAS.Each method was compared and analyzed in terms of dissolution in ammonium nitrogen(NH_(4)^(+)-N)and soluble COD(SCOD)in EAS.Furthermore,the removal of tetracycline resistance genes(TRGs)and class 1 transposon gene intI1 from EAS was investigated.The NH_(4)^(+)-N and SCOD concentrations in EAS treated by PTH were 1.24 and 2.58 times higher than those of TH.However,the removal efficiency of total TRGs and intI1 between the groups was comparable.The SCOD concentration of the PTH+NaOH group was 4.37 times higher than that of the PTH group,and the removal efficiency of total TRGs was increased by 9.52%compared with that by PTH.The NH_(4)^(+)-N and SCOD concentrations of the PTH+CaO group could reach 85.04%and 92.14%of the PTH+NaOH group,but the removal efficiency of total TRGs by PTH+CaO was 19.78%lower than that by PTH+NaOH.Thus,to reduce the financial cost in actual operation,lime(CaO)can be used instead of a strong alkali(NaOH),and pasteurized steam at 70℃ instead of conventional high-temperature heating to treat EAS.This study provides a reference for the development of alkaline hydrolysis under moderate temperatures along with the removal of TRGs in EAS.

Catalytic Hydrolysis of CFC-12 over MoO_(3)/ZrO_(2)-TiO_(2)

Solid acid MoO_(3)/ZrO_(2)-TiO_(2)catalysts were prepared by impregnation method,and catalytic hydrolysis of difluorodichloromethane(CFC-12)over the catalyst was studied.The presence of MoO_(3)/ZrO_(2)-TiO_(2)catalyst in polycrystalline state could be clearly observed by transmission electron microscopy(TEM).Mesopores were detected by N2 adsorption-desorption isotherms which further confirmed the MoO_(3)/ZrO_(2)-TiO_(2)structural characteristics of catalyst.The results of NH_(3)-TPD showed that the calcination temperatures had a great influence on the acidity of the catalyst,and the weak acidic site had a strong catalytic activity for the catalytic hydrolysis of CFC-12.Moreover,ZrO_(2)-TiO_(2)was highly dispersed in the MoO_(3)framework,suggested by powder X-ray diffraction(XRD)and N_(2)adsorption-desorption results.The effects of the catalyst calcination temperatures on the conversion rate of CFC-12 were studied.The effects of catalytic hydrolysis temperatures and water vapor concentration on the catalytic hydrolysis rate of CFC-12 were also studied.The solid acid MoO_(3)/ZrO_(2)-TiO_(2)was calcined at 500℃for 3 h at a catalytic hydrolysis temperature of 400℃and water vapor concentration of 83.18%,and catalytic hydrolysis rate of CFC-12 reached 98.65%.The hydrolysis rate of CFC-12 remained above 65.34%after 30 hours continuous reaction.

Glucosinolates and Their Hydrolysis Products in Arabidopsis thaliana Influence Performance and Feeding Choice of Pieris rapae and Spodoptera exigua

Glucosinolates and their hydrolysis products, found in plants of the order Brassicales, are well-known for their defensive properties against insect herbivores. Arabidopsis thaliana (Col-0) genetic lines with mutations that modify the type of glucosinolates (i.e. myb28myb29 and cyp79B2cyp79B3 are deficient in the production of aliphatic and indolyl glucosinolates, respectively) make it possible to test for the specific effects of these secondary chemicals on insect herbivores. The Pad3 mutant (deficient in camalexin), which has a role in resistance to pathogens, was also tested. Likewise, the effects of different glucosinolate hydrolysis products can be evaluated using genetically modified (GM) lines of the wild type Col-0 ecotype, which naturally produces isothiocyanates. These GM lines include the nitrile-producing 35S: ESP and the double knockout tgg1tgg2, which virtually lacks hydrolysis products. In both no-choice and choice experiments, the crucifer specialist Pieris rapae was virtually unaffected by differences in the type of glucosinolates or hydrolysis products. In contrast, the generalist insect Spodoptera exigua had statistically significant increases in pupae/adult weight and faster developmental times when reared on mutants deficient in the production of aliphatic and indolyl glucosinolates and their hydrolysis products. There were no differences in the performance of either insect species when reared on wild type Col-0 or Pad3. Results from feeding choice trials showed that Pieris rapae had no statistically significant preference for any of the genetic lines. In contrast, Spodoptera exigua had a significant feeding preference for the double mutant tgg1tgg2. This study provides evidence that variation in the type of glucosinolates and their hydrolysis products can influence insect performance and feeding choices, and that responses are species-specific.

羊乳清蛋白部分和深度水解工艺、水解物致敏性及肽谱分析

利用羊乳清蛋白制备低致敏性配料是目前乳品工业的研究热点。乳清蛋白是乳中主要的蛋白质之一,也是引起婴幼儿过敏反应的主要成分,将蛋白质水解为小分子肽是降低其致敏性的有效方法。以山羊乳清蛋白为原料,研究了部分水解乳清蛋白和深度水解乳清蛋白的水解工艺和水解物特性(水解度、分子质量分布和β-乳球蛋白抗原性),并利用液相色谱串联质谱法(L C-MS/MS)比较了部分水解和深度水解工艺中过敏表位酶切位点的差异。研究结果表明,中性蛋白酶和碱性蛋白酶对羊乳清蛋白水解效果较好,其中碱性蛋白酶的水解度最高,达21.26%。经电泳分析,单酶水解后的产物中仍存在大分子多肽链,深度水解工艺需要复合酶水解。在酶底比为4000 U/g时,使用碱性蛋白酶在pH值为10.0、温度为55℃条件下水解羊乳清蛋白1.0 h,部分水解产物的水解度为12.31%,分子质量在5 kDa以下的多肽占95.18%,β-乳球蛋白抗原性下降率为9.40%。中性蛋白酶和碱性蛋白酶的质量比为1∶1,酶底比为6000 U/g,在pH值为8.5、温度为50℃条件下,水解羊乳清蛋白3.0 h,深度水解产物的水解度为35.58%,分子质量低于3 kDa的多肽为97.26%,β-乳球蛋白抗原性下降率为40.97%。部分水解和深度水解均能破坏β-乳球蛋白的大部分过敏表位,但相较于部分水解,深度水解能更大程度地降低乳清蛋白的致敏性。研究旨在为低致敏性羊水解乳清蛋白的生产提供一定的理论参考。

碱性蛋白酶水解时间对玉米谷蛋白理化性质及抗氧化活性的影响

为探究碱性蛋白酶(alcalase)水解对玉米谷蛋白理化性质及抗氧化活性的影响,对不同水解时间获得的玉米谷蛋白水解物的表面疏水性、二硫键含量、热性能、分子质量分布、抗氧化活性等进行了评价。结果表明:碱性蛋白酶水解对玉米谷蛋白的性质有显著影响,分子质量和二硫键含量显著降低(P<0.05),与玉米谷蛋白相比其水解物具有较高的溶解性、起泡性、乳化性和热稳定性。此外,玉米谷蛋白水解产物具有良好的抗氧化性能,当水解时间为150 min时玉米谷蛋白水解物的DPPH自由基清除为(54.46±1.43)%,羟自由基(·OH)清除率为(74.06±1.49)%,Fe^(2+)螯合力为(86.69±1.35)%。

聚氨酯和环氧树脂涂层耐水性能对比研究

本文选择了不同类型的聚氨酯(PU)涂层和环氧树脂(EP)涂层作为代表,通过红外光谱、固态核磁共振、热失重分析和热力学性能分析,研究了长期水下浸泡对涂层结构和性能的影响,并进一步对比了上述不同材料的水解稳定性。结果表明,聚醚型聚氨酯(PTMG-PU)涂层具有最优的耐水性,并且其化学结构基本没发生化学水解作用,然而加入陶瓷增强颗粒会降低材料的耐水性,并可能加速水解作用对涂层结构和性能的影响;相同水解条件下,聚酯型聚氨酯(PEA-PU)和EP涂层在水中的耐水性较差,并且可能发生聚合物链的化学水解作用,进而导致材料储能模量的提高。

一种能温和产氢且具有高活性保持能力的Al-Bi-Zn基复合粉体

通过相图计算和气体雾化的方法,设计并制备Al-10Bi-7Zn和Al-10Bi-7Zn-1.5X (X:Cu, Fe, Ni)(质量分数,%)复合粉体。研究Cu、Fe和Ni对Al-Bi-Zn基复合粉体水解制氢性能的影响。通过X射线衍射(XRD)和扫描电子显微镜(SEM)以及能量色散谱(EDS)分析对粉体的组成和形貌进行表征。水解制氢性能测试结果表明,添加Cu、Fe或Ni可以改变Al-10Bi-7Zn三元合金复合粉体的制氢速率,并且提高其抗氧化性能。在四元复合粉体体系中,Al-10Bi-7Zn-1.5Ni表现出最佳的制氢性能,在60℃下与蒸馏水反应时,500 min内的产氢率为75.3%(954.1 m L/g),在储存7 d后(30℃,相对湿度60%),1500 min内保持57.9%(733.7 m L/g)的产氢率。此外,机理研究表明,在Al-Bi-Zn基复合粉体中添加Cu、Fe或Ni可以稳定Al基体,抑制复合粉体在空气中的开裂,保持粉体的高活性。

湖南植烟水稻土碱解氮分布特征及其影响因素

为明确湖南植烟水稻土碱解氮含量、空间分布和影响因素,检测了2698个耕层土壤样本的碱解氮含量,分析了其空间分布特征及丰缺状况,探讨了其与种植制度、耕层厚度、海拔和土壤pH、有机质、颗粒组成之间的关系。土壤碱解氮变幅为57.10~447.40 mg/kg,平均为183.78 mg/kg,碱解氮适宜(110~180 mg/kg)的样本占比为46.55%;安仁县、桂阳县和临武县等10个县(区)土壤碱解氮平均值较高,其他16县(区)都在适宜范围;土壤碱解氮空间分布有从东南向西北递减的分布趋势;烟-玉米轮作的土壤碱解氮相对较低;土壤碱解氮随耕层深度、土壤pH、有机质增加而增加,与海拔呈抛物线关系(峰值在海拔150~250 m区间),随土壤粉砂占比增加而升高,随粗砂占比增加而降低。湖南植烟水稻土碱解氮含量空间分布不均匀,且受多种因素影响,要因地制宜分区制定氮肥施用策略。

2-氨基苯甲酰胺衍生物的合成与应用

以2-氨基苯甲腈衍生物(2a~2f)为原料,在氢氧化钾碱性条件下发生水解反应合成了2-氨基苯甲酰胺衍生物(1a~1f),对合成条件进行了优化,通过1 HNMR对产物结构进行了表征。结果表明,在氢氧化钾用量n(KOH)∶n(2a)为4∶1、回流反应14 h的最佳条件下,衍生物1a的收率达到84%;以多聚磷酸为催化剂,衍生物1a与苯甲醛在微波辅助下可以合成7-甲基-2-苯基-2,3-二氢喹唑啉-4(1 H)-酮(3)。

不同酶解程度对留胚米粉理化性质及消化性的影响研究

研究不同酶解程度对留胚米粉理化性质及消化性的影响,以留胚米为原料,制备不同酶解程度的留胚米粉,考察不同酶解程度对留胚米粉的营养成分、色度、粒径、水合特性、糊化特性、红外光谱和体外消化特性的影响。结果表明,留胚米粉经过不同酶解时间处理后,淀粉含量降低,淀粉粒径减小;淀粉结块率先减小后增大,当DE值为19.98%±0.78%时淀粉结块率最低;淀粉分散时间缩短,溶解度增大;酶解米粉中淀粉的峰值黏度、谷值黏度、衰减值、最终黏度、回生值和淀粉黏度到达峰值的时间均显著降低;且淀粉的短程有序性受到破坏;快消化淀粉(RDS)含量显著增加。综上所述,当DE值为19.98%±0.78%时,酶解留胚米粉的综合性质最佳。

超声波-酶法协同制备梅花鹿鹿血肽及其体内抗疲劳活性研究

目的采用超声波辅助生物酶法协同制取鹿血肽,研究酶解条件对鹿血肽得率的影响。方法通过单因素和正交实验优化混合蛋白酶不同酶解时间、酶解温度、加酶量、pH。以小鼠游泳时间为指标,研究鹿血多肽的抗疲劳活性。结果鹿血酶解的温度为50℃、酶解时间为4.0 h、加酶量5.5%、pH 7.5为较优酶解条件,此时水解度为29.10%。小鼠抗疲劳实验显示:鹿血多肽高、中、低剂量组小鼠游泳力竭时间延长率分别为159.46%、91.89%、13.51%,与对照组相比,鹿血多肽高、中剂量组游泳力竭时间均显著延长(P<0.05);鹿血多肽高剂量组小鼠游泳力竭后,解剖检测发现肝脏中肝糖原含量以及血液中的尿素氮浓度、乳酸含量均显著提升(P<0.05),明显提高运动后小鼠机体代谢活动,增强其抗疲劳能力。结论本研究为进一步研究梅花鹿鹿血肽的抗疲劳机制和开发鹿血肽酒等相关产品奠定了基础。