Phase-Modulation of Iron/Nickel Phosphides Nanocrystals “Armored” with Porous P-Doped Carbon and Anchored on P-Doped Graphene Nanohybrids for Enhanced Overall Water Splitting

Transition metal phosphides (TMPs) nanostructures have emerged as important electroactive materials for energy storage and conversion. Nonetheless, the phase modulation of iron/nickel phosphides nanocrystals or related nanohybrids remains challenging, and their electrocatalytic overall water splitting (OWS) performances are not fully investigated. Here, the phase-controlled synthesis of iron/nickel phosphides nanocrystals “armored” with porous P-doped carbon (PC) and anchored on P-doped graphene (PG) nanohybrids, including FeP–Fe₂P@PC/PG, FeP–(Ni_xFe_1-x)₂P@PC/PG, (Ni_xFe_1-x)₂P@PC/PG, and Ni₂P@PC/PG, are realized by thermal conversion of predesigned supramolecular gels under Ar/H₂ atmosphere and tuning Fe/Ni ratio in gel precursors. Thanks to phase-modulation-induced increase of available catalytic active sites and optimization of surface/interface electronic structures, the resultant pure-phase (Ni_xFe_1-x)₂P@PC/PG exhibits the highest electrocatalytic activity for both hydrogen and oxygen evolution in alkaline media. Remarkably, using it as a bifunctional catalyst, the fabricated (Ni_xFe_1-x)₂P@PC/PG || (Ni_xFe_1-x)₂P@PC/PG electrolyzer needs exceptional low cell voltage (1.45 V) to reach 10 mA cm⁻² water-splitting current, outperforming its mixed phase and monometallic phosphides counterparts and recently reported bifunctional catalysts based devices, and Pt/C || IrO₂ electrolyzer. Also, such (Ni_xFe_1-x)₂P@PC/PG || (Ni_xFe_1-x)₂P@PC/PG device manifests outstanding durability for OWS. This work may shed light on optimizing TMPs nanostructures by combining phase-modulation and heteroatoms-doped carbon double-confinement strategies, and accelerate their applications in OWS or other renewable energy options.     

Designed formation of CoS2 nanoboxes with enhanced oxygen evolution reaction electrocatalytic properties

Hollow nanostructures with their intriguing structural features are attractive for efficient energy conversion and storage technology. Herein we report the designed construction of novel CoS₂ nanoboxes by employing the Co-based zeolitic imidazolate (ZIF-67) nanocubes (NCs) as the starting template. Delicate manipulation of the template-engaged reaction time between thioacetamide (TAA) and ZIF-67 NCs leads to the formation of hollow CoS₂ nanostructures. As a result of the unique nanobox structure, the optimized CoS₂ nanoboxes (NBs) have an enlarged electrolyte-accessible surface, abundant mass diffusion pathways, and high structural integrity, which afford the current density of 10 mA cm⁻² at a low overpotential of 290 mV for oxygen evolution reaction (OER) in 1 M KOH solution. Remarkably, these CoS₂ NBs could also display excellent long-term stability for more than 40 h electrochemical test in an alkaline medium, showing a class of advanced electrocatalysts for OER and beyond.     

基于纳米材料的葡萄糖传感器测试系统设计

研究了一种基于纳米材料的新型电化学非酶葡萄糖传感器测试系统的设计方法。在2M的KOH溶液中,Pd—Ni／SiNWs（钯-镍/硅纳米线）电极在脉冲扫描电压作用下,对溶液中葡萄糖分子有良好电催化氧化作用,回路中会产生催化氧化电流,可以通过峰值电流保持器对回路电流进行监控,把回路中与葡萄糖催化氧化过程相对应的电流峰值记录下来,作为检测葡萄糖浓度的依据。根据上述原理,开发出了一种含可控波形电压输出、电流峰值采集、显示输出以及键盘控制等功能模块的葡萄糖传感器测试系统。     

Preparation and electrocatalytic properties of Ti/IrO2-Ta2O5 anodes for oxygen evolution

1 Introduction Oxygen and chlorine evolution reaction are the common and most important electrochemical reactions in electrolysis industry. As the Ti/RuO2-TiO2 anode has been successfully developed and widely employed in the electrochemical industry, the …     

Morphology and Structure Engineering in Nanofiber Reactor: Tubular Hierarchical Integrated Networks Composed of Dual Phase Octahedral CoMn2O4/Carbon Nanofibers for Water Oxidation

1D hollow nanostructures combine the advantages of enhanced surface‐to‐volume ratio, short transport lengths, and efficient 1D electron transport, which can provide more design ideas for the preparation of highly active oxygen evolution (OER) electrocatalysts. A unique architecture of dual‐phase octahedral CoMn₂O₄/carbon hollow nanofibers has been prepared via a two‐step heat‐treatment process including preoxidation treatment and Ostwald ripening process. The hollow and porous structures provide interior void spaces, large exposed surfaces, and high contact areas between the nanofibers and electrolyte and the morphology can be engineered by adjusting the heating conditions. Due to the intimate electrical and chemical coupling between the oxide nanocrystals and integrated carbon, the dual‐phase octahedral CoMn₂O₄/carbon hollow nanofibers exhibit excellent OER activity with overpotentials of 337 mV at current density of 10 mA cm^?2 and Tafel slope of 82 mV dec^?1. This approach will lead to the new perception of design issue for the nanoarchitecture with fine morphology, structures, and excellent electrocatalytic activity.     

掺氮金刚石电极性能及其氧化降解硝基苯研究

采用热阴极直流辉光等离子体化学气相沉积法制备亚微米晶氮掺杂金刚石膜(NDD), 采用SEM分析样品的表面形貌, 分别用Hall测试和循环伏安法测试氮掺杂金刚石电极的电学和电化学性能。实验结果表明, 当氮气流量低于30 sccm时, 膜的电导率随氮气流量的增大略有提高; 氮气流量继续增大则电导率迅速下降, 电导率最大为5.091 S/cm。氮掺杂金刚石电极具有较好的伏安性能, 在酸性、中性和碱性介质中均具有较宽的电位窗口和较低的背景电流。以硝基苯为目标污染物测试NDD材料作为阳极氧化降解的电催化性能。在0.1 mol/L Na₂SO₄溶液的支持电解质中, 以氮掺杂金刚石为阳极降解0.5 mmol/L的硝基苯, 反应时间300 min, 硝基苯的降解率达到94%, 化学需氧量(COD)去除率约68%。     

量子点敏化太阳电池FTO/CoS/CuS对电极的制备与性能

摘要：本文采用恒电位电沉积方法在FTO导电玻璃表面依次沉积CoS和CuS,形成 FTO/CoS/CuS复合对电极用于量子点敏化太阳电池。确定了电沉积电位和电沉积时间,并研究了电沉积温度对电极形貌及电催化活性的影响。对电极的表面形貌和微观结构采用SEM和TEM方法进行表征;对电极的光反射性能采用紫外可见分光光度计进行测试;对电极的电化学性能通过测试交流阻抗、Tafel极化曲线以及J-V曲线进行表征。研究结果表明,FTO/CoS/CuS对电极与电解液界面处的电荷转移阻抗较低,具有更高的光反射率及电催化活性。与Au片、FTO/CoS和FTO/CuS对电极相比,光电转化效率分别提高了132.9%,46.6%,26.9%。     

碳纸负载钴氧化物的制备及电催化析氧性能研究

高效且廉价的电催化析氧反应（OER）电极材料的制备对其在电化学能源转化和储存系统中的应用具有重要的研究意义。通过溶剂热法和不同气氛焙烧,分别制得碳纤维纸（碳纸）负载的两种钴氧化物（一氧化钴和四氧化三钴）,并将其用作OER电极的催化剂。运用X射线衍射仪（XRD）、场发射扫描电镜（FESEM）和X射线光电子能谱（XPS）技术分别对两种材料的物相、形貌和表面价态进行了表征及分析。结果表明：在氮气气氛下焙烧得到一氧化钴纳米片,而在空气下焙烧得到四氧化三钴纳米片。通过线性扫描伏安法（LSV）、循环伏安曲线（CV）、电化学交流阻抗测试（EIS）和计时电位法对两种材料的电催化析氧性能进行了研究。结果表明：一氧化钴电极比四氧化三钴电极具有更优异的析氧反应催化活性和稳定性。在1 mol/L 氢氧化钾电解液中,一氧化钴和四氧化三钴电极在10 mA/cm ²电流密度下对应的电位分别为1.568 V和1.617 V。     

Electrocatalytic Upgrading of Lignin‐Derived Bio‐Oil Based on Surface‐Engineered PtNiB Nanostructure

The development of robust electrocatalysts for electrocatalytic hydrogenation (ECH) of guaiacol and related lignin model monomers is necessary for the stabilization or upgrading of bio‐oil. Additionally, the efficiency of biomass conversion to bio‐oil products remains below the minimum requirements for its implementation at scale. Herein, a PtNiB/CMK‐3 catalyst with pronounced ECH performance in the conversion of guaiacol and related model lignin monomers to bio‐oil under optimally mild conditions, through a modulation strategy that modified the electronic structure of PtNi via boron alloying, is prepared. Notably, the optimized PtNiB/CMK‐3 exhibited an inspiring high faradaic efficiency of 86.2%, which is significantly higher (13.7 times) than that of the PtNi/CMK‐3 without B‐doping (6.3%). Experimental results and theoretical calculations showed that the B‐doping optimized the PtNiB alloy surface electron structure, simultaneously promoting substrate and intermediate adsorption and the ECH process. In addition, the uniform dispersion of PtNiB nanoparticles embedded within the mesoporous channels of CMK‐3 ensures an enhanced utilization efficiency, leading to improvements in stability and bio‐oil product generation. The lab‐scale ECH experiment of guaiacol also certified the scale‐up potential. This work opens a promising avenue to the rational design of advanced and highly efficient electrocatalysts for biomass upgrading.     

低温共沉淀法合成多孔CoFe LDH纳米片电催化剂

通过低温共沉淀技术合成了多孔CoFe层状双金属氢氧化物（CoFe LDH）纳米片。运用X射线衍射（XRD）、X射线光电子能谱（XPS）、扫描电镜（SEM）、透射电镜（TEM）等手段对产物的物相、组成及微观形貌进行了表征,并探讨了铁离子（Fe³⁺）含量对CoFe LDH纳米结构生长行为的影响,考察了制备的产物作为电催化剂在电解水析氧反应中的性能。结果表明,Fe³⁺的加入可以有效调节产物的形貌、结晶度和孔道结构。在合适的Co与Fe比例条件下,制备的CoFe LDH可形成多孔纳米片,且增大了总孔体积,增加了表面活性位点。同时,结晶CoFe LDH纳米片可促进Co和Fe离子间的电荷转移行为,从而提高产物的电催化活性。对于电解水析氧反应,当电流密度为10 mA/cm²时,结晶Co_0.67Fe_0.33 LDH多孔纳米片所需的过电势仅为291 mV,Tafel斜率为33 mV/dec,并展现出良好的循环稳定性。