Zinc-Deficiency Induced g-C3N4 Nanosheets: Photocatalytic Nitrogen Fixation Study and Carrier Dynamics

Catalysis Letters - g-C3N4 has great application prospect in the field of photocatalytic nitrogen fixation owing to the advantages of abundant raw materials, low toxicity, low consumption, high...     

Carbon vacancies improved photocatalytic hydrogen generation of g-C3N4 photocatalyst via magnesium vapor etching

Vacancies engineering was widely reported as the promising strategy for the improvement of the photocatalytic performance of semiconductor photocatalysts. In current work, carbon vacancies are constructed successfully in graphitic carbon nitride (g-C₃N₄) photocatalyst via magnesium vapor etching. Experimental results show that the formed carbon vacancies in g-C₃N₄ photocatalyst can significantly improve the photocatalytic H₂ generation performance. XRD, FTIR, SEM/TEM, XPS and PL characterization data are employed to evidence the construction of carbon vacancies, which are revealed to be the reason for the enhancement of photocatalytic H₂ evolution. This work develops an alternative route to construct carbon vacancies in g-C₃N₄ materials and gives an insight into the influence of vacancies on the photocatalytic performance of photocatalysts.     

Fabricating NixCo1−xO@C cocatalysts sensitized by CdS through electrostatic interaction for efficient photocatalytic H2 evolution

Exploiting efficient and stable noble metal-free hydrogen evolution catalysts for water splitting is of great importance. In this work, Ni_xCo_1-xO@C/CdS hybrid is successfully fabricated through an electrostatic interaction of oppositely charged nanoparticles on their surfaces. The resulting Ni_xCo_1-xO@C nanoboxes cocatalysts which were derived from NiCo-LDH@ZIF-67 with Ni–Co layered double hydroxides (LDH) decorated with ZIF-67 precursor exhibited improved hydrogen production rate compared with bare CdS semiconductor from 0.7 mmol g⁻¹ h⁻¹ to 56 mmol g⁻¹ h⁻¹. It is demonstrated that the electrostatic interaction between the two surface charged nanoparticles of Ni_xCo_1-xO@C and CdS play an important role in migrating and separating of photogenerated charge carriers. The synthesized Ni_xCo_1-xO@C as excellent candidates for cost-effective cocatalysts is aimed to substitute for noble metals in photocatalytic H₂ evolution.     

A one-pot sealed ammonia self-etching strategy to synthesis of N-defective g-C3N4 for enhanced visible-light photocatalytic hydrogen

Photocatalytic hydrogen (H₂) evolution from water is considered as a prospective approach, which can convert inexhaustible solar energy into chemical energy to alleviate energy crisis and environmental problems. Herein, the N-defective g-C₃N₄ with porous structure was firstly synthesized in a sealed crucible by one-step thermal polymerization method. The experimental data showed that the yield of the catalyst was obviously increased under sealing condition. Moreover, the N-defective g-C₃N₄ prepared from urea precursor under sealed condition reached an optimum photocatalytic H₂ production rate of 597.4 μmol/h and an apparent quantum efficiency of 15.6% at wavelength of 420 nm. This enhanced photocatalytic H₂ production performance is mainly ascribed to the introduction of N-defects, which not only extended of the visible light absorption, but also acted as the electron trap centers to suppress the recombination of the photogenerated electron and hole pairs. This work offers one-step facile strategy for the introduction of N-defects to prepare N-defective g-C₃N₄ with superior photocatalytic activity, which is also a great substitute for the high-energy consuming and complicated synthetic routes.     

改性壳聚糖微球处理含氟废水的研究

利用无毒交联剂制备壳聚糖微球并负载稀土元素,制得新型除氟吸附剂。配制水除氟实验中,Ce-CEB对F^-(纯NaF溶液)的静态吸附容量为17.7 mgF^-/g微球,F^-的脱除率为93.4%;对于具有复杂阴离子的配制水,Ce-CEB对F^-的动态饱和吸附量为12.3 mgF^-/g微球。     

惠来地区蔬菜土壤中Pb和As的形态分析

采用七步提取法对惠来蔬菜土壤中的重金属Pb和As进行形态分析,并研究了Pb和As的生物可给性,结果表明Pb和As的分布以残渣态为主,Pb的生物可利用态含量较少,当环境改变时,As的生物可给性可能存在潜在的危害。     

分析化学网络智能组卷系统的开发

为了进一步推动教学改革,促进教学质量的提高,我们开发了分析化学智能组卷系统,介绍了智能组卷系统开发的意义、开发过程、主要特色及使用效果,并对开发前景进行了展望。结果表明:该网络智能组卷系统具有客观性强、时间快、易于控制试卷难度等特点,深受师生和专家好评。     

变压器油在线监测技术发展现状及其校验方法探究

智能电网的发展需求是变压器油在线监测技术产生的根源,分析目前在线监测技术发展现状,进而引出对变压器油在线监测装置监测有效性的思考,并对现有变压器油在线监测装置有效性校验方法优劣性对比分析,最后得出研究变压器油中溶解气体在线监测装置校验技术的意义和研究方向。     

碳基固体酸催化剂的制备及催化合成油酸甲酯

以蔗糖和对甲基苯磺酸混合物为原料,采用水热法一步合成了碳基固体酸催化剂,用于催化油酸和甲醇酯化合成油酸甲酯。考察了催化剂用量、原料配比、反应时间及催化剂重复使用性等对酯化率的影响。结果表明,适宜反应条件为:催化剂用量为油酸质量的3.54%,醇酸摩尔比6∶1,反应时间7 h,酯化率可达94.96%。该催化剂尚具有一定的重复使用性。     

玄武岩纤维增强磷酸镁水泥砂浆力学性能试验研究

以磷酸镁水泥砂浆3 d、7 d和28 d的抗压、抗折和拉伸黏结强度为评判指标,研究了玄武岩纤维对磷酸镁水泥砂浆力学性能的影响,建立了声波纵波脉冲速度与抗压强度的理论关系式。结果表明,掺量不超过2 kg/m^3的玄武岩短切纤维有助于提高砂浆的抗压强度;短切玄武岩纤维的掺入可以显著增强砂浆的抗折强度,建议掺量为3~5.5 kg/m^3;砂浆的拉伸黏结强度会随纤维掺量的增加而提高,建议掺量为5~6 kg/m^3;纵波波速可以用于测定磷酸镁水泥修补砂浆的抗压强度。