钛丝负载Pt/TiO2电极的制备及其电催化测定化学需氧量研究

采用阳极氧化的方法,在钛丝上制备TiO2纳米管阵列薄膜,用恒电流沉积的方法在TiO2纳米管表面沉积Pt纳米晶,制备了钛丝负载的Pt/TiO2电极.用SEM对电极的形貌进行了表征,纳米管长度在3.5～10 μm之间与氧化电压和氧化时间密切相关,Pt纳米晶均匀沉积在TiO2纳米管表面.用极化曲线、循环伏安曲线、电流-时间曲线对Pt/TiO2电极的电催化性能进行表征.当沉积电流密度大于1.0 mA/cm2时,制备的Pt/TiO2电极的电催化性能显著高于Pt电极.而且,在甲醛等五种有机物溶液中的电催化结果表明,净电流和理论COD之间表现出很好的线性相关性,说明钛丝负载的Pt/TiO2电极可用于电催化快速检测水体中的化学需氧量.     

掺杂铁的二氧化铅电极的制备及性能研究

主要研究了不锈钢/PbO₂电极和掺杂的不锈钢/Fe-PbO₂电极的制备,用其对有机废水的处理效果及影响因素来评价该电极的性能。实验结果表明:采用恒流阳极电沉积技术制备的PbO₂电极,掺杂和不掺杂铁的电极主要成分都是β-PbO₂;两电极外观都没有明显的裂纹等缺陷,掺杂铁的二氧化铅镀层颗粒大小镶嵌,很好地清除了内应力,保证了基材与镀层不易脱落,未掺杂铁的二氧化铅镀层颗粒细小、均匀,内应力有些大;将Fe（NO₃）₂添加至电沉积溶液中,致使PbO₂电沉积层的析氧电位向正方向移动,改善了PbO₂电极的电催化活性,以至于更有利于氧化降解有机物。用改性的Fe-PbO₂电极和常规的PbO₂电极分别降解初始浓度相同的邻苯二酚和苯酚有机物废水,改性的Fe-PbO₂电极对苯酚和邻苯二酚的去除率均高于常规的PbO₂电极。掺杂铁的二氧化铅电极较未掺杂电极有更好的电催化活性,更高的析氧电位,更适宜于用作电催化阳极。     

Application of electrode materials and catalysts in electrocatalytic treatment of dye wastewater

The dye industry produces a large amount of hazardous wastewater every day worldwide, which brings potential threaten to the global environment. As an excellent method for removal of water chroma and chemical oxygen demand, electrocatalytic methods are currently widely used in the treatment of dye wastewater. The selection and preparation of electrode materials and electrocatalysts play an important role on the electrocatalytic treatment. The aim of this paper is to introduce the most excellent high-efficiency electrode materials and electrocatalysts in the field of dye wastewater treatment. Many electrode materials such as metal electrode materials, boron-doped diamond anode materials and three-dimensional electrode are introduced in detail. Besides, the mechanism of electrocatalytic oxidation is summarized. The composite treatment of active electrode and electrocatalyst are extensively examined. Finally, the progress of photo-assisted electrocatalytic methods of dye wastewater and the catalysts are described.     

乙二醇高温还原制备燃料电池核壳结构Cu@Pt-Pd电极的研究

通过对以碳为核心的燃料电池电催化剂Cu@Pt-Pd的制备方法的研究,以还原法成功将Cu、Pt、Pd还原到了靶核C上制备出了核壳结构电催化剂Cu@Pt-Pd。该催化剂以Cu为核来提升催化剂的表面积比,同时掺杂金属Pd,降低贵金属铂的使用量,在提高催化效率的同时可以降低成本。经过对所制备的催化剂的XRD和CV的测试与分析,探究出制备的成品具有一定的提升氧化还原反应的催化效率的能力,同时该制备方法简单易于操作,利于大量制备。     

新型包覆碳化钨载体负载Pd催化剂的性能

以Vulcan XC-72R活性碳作为碳源,采用高温热处理还原法,在活性碳表面原位还原钨酸铵,形成表面包覆钨的碳化物结构的载体。通过BET等当钨酸铵用量适宜时,形成的钨的碳化物的平均孔径较大,较大介孔所占比例较大,以其为载体制备的Pd催化剂Pd/WC-2其电荷传递阻抗和扩散阻抗都较小。催化剂Pd/WC-2对甲酸的氧化不但具有较高的活性,同时也具有很好的稳定性。     

Study of electrocatalysts for oxygen reduction based on electroconducting polymer and nickel

The properties and electrocatalytic activity were studied of composite carbon‐supported materials based on heterocyclic polymer and nickel, in particular carbon/polyaniline/nickel, carbon/polypyrrole/nickel, carbon/poly(3‐methylthiophene)/nickel, as well as their precursors, carbon/polyaniline, carbon/polypyrrole, and carbon/poly(3‐methylthiophene). The materials were characterized by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), EDAX, and electrochemical methods, such as cyclic voltammetry and linear voltammetry using RDE. SEM show porous materials, with a particle size of around 0.3 μm. It was found that in nickel‐modified catalysts between 5 and 6 wt % of nickel is obtained. TGA and FTIR show that the modification with nickel alters the polymer bonds. Curves from cyclic voltammetry show cathodic peaks corresponding to the oxygen reduction reaction (ORR) in all materials, occurring at relatively low potentials. Based on the potential range for ORR as well as kinetic parameters obtained from linear voltammetry using RDE, it was concluded that C‐Ppy‐Ni shows the best performance for ORR in acidic medium. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Hexagonal Co9S8: Experimental and Mechanistic Study of Enhanced Electrocatalytic Hydrogen Evolution of a New Crystallographic Phase

The crystallographic phase is one of the most important parameters in determining the physicochemical properties of an electrocatalyst. However, existing understanding of phase-performance relationship is still very limited, especially for unconventional phases. Herein, the experimental discovery of the hexagonal close-packed (hcp) phase of Co₉S₈ is presented. This is the first demonstration of the hexagonal phase of Co₉S₈, and through correlated experimental and computational data, the first to elucidate the origin of enhanced catalytic performance from this new phase. The synthesized Fe doped Co₉S₈-hcp (Fe@Co₉S₈-hcp) catalyst, compared to its face-centered cubic (fcc) phase, exhibits small overpotentials of 44.1 and 298 mV at 10 mA and 500 mA cm⁻² for the hydrogen evolution reaction (HER), respectively. Mass activity is enhanced by 64.9 folds compared to the conventional Co₉S₈-fcc at 300 mV, which is the best among all Co₉S₈-based catalysts ever reported. Density functional theory calculations reveal that the enhanced HER of Fe@Co₉S₈-hcp mainly occurs at the Co sites, which synergizes with the doped Fe playing the role of coordination to strengthen H₂O adsorption and dissociation. This study opens a new avenue for designing high-performance electrocatalysts with unconventional phases for energy and environmental applications.     

Large-Scale,Controllable Synthesis of Ultrathin Platinum Diselenide Ribbons for Efficient Electrocatalytic Hydrogen Evolution

2D platinum diselenide (PtSe₂) exhibits exceptional layer-dependent electrical properties and high catalytic activity for hydrogen evolution reactions, making it an ideal system for studying structure–activity correlations. However, the synthesis of high-quality atomically thin PtSe₂ materials has proven challenging. This study presents a simple chemical vapor deposition method for synthesizing high-quality ultrathin 1T-PtSe₂ ribbons on Au foils, making it easily applicable. Theoretical and experimental results confirm that these atomically thin 1T-PtSe₂ ribbons possess abundant catalytic sites and can serve as ideal electrocatalysts. This study advances the large-scale synthesis and potential application of ultrathin transition metal disulfides and presents a novel method for designing and synthesizing highly active ultrathin catalysts.     

Designing N-Confused Metalloporphyrin-Based Covalent Organic Frameworks for Enhanced Electrocatalytic Carbon Dioxide Reduction

Electrochemical conversion of carbon dioxide (CO₂) into value-added products is promising to alleviate greenhouse gas emission and energy demands. Metalloporphyrin-based covalent organic frameworks (MN₄-Por-COFs) provide a platform for rational design of electrocatalyst for CO₂ reduction reaction (CO₂RR). Herein, through systematic quantum-chemical studies, the N-confused metallo-Por-COFs are reported as novel catalysts for CO₂RR. For MN₄-Por-COFs, among the ten 3d metals, M = Co/Cr stands out in catalyzing CO₂RR to CO or HCOOH; hence, N-confused Por-COFs with Co/CrN₃C₁ and Co/CrN₂C₂ centers are designed. Calculations indicate CoN_xC_y-Por-COFs exhibit lower limiting potential (−0.76 and -0.60 V) for CO₂-to-CO reduction than its parent CoN₄-Por-COFs (−0.89 V) and make it feasible to yield deep-reduction degree C₁ products CH₃OH and CH₄. Electronic structure analysis reveals that substituting CoN₄ to CoN₃C₁/CoN₂C₂ increases the electron density on Co-atom and raises the d-band center, thus stabilizing the key intermediates of the potential determining step and lowering the limiting potential. For similar reason, changing the core from CrN₄ to CrN₃C₁/CrN₂C₂ lowers the limiting potential for CO₂-to-HCOOH reduction. This work predicts N-confused Co/CrN_xC_y-Por-COFs to be high-performance CO₂RR catalyst candidates. Inspiringly, as a proof-of-concept study, it provides an alternative strategy for coordination regulation and theoretical guidelines for rational design of catalysts.     

Interface Density Engineering on Heterogeneous Molybdenum Dichalcogenides Enabling Highly Efficient Hydrogen Evolution Catalysis and Sodium Ion Storage

Constructing active heterointerfaces is powerful to enhance the electrochemical performances of transition metal dichalcogenides, but the interface density regulation remains a huge challenge. Herein, MoO₂/MoS₂ heterogeneous nanorods are encapsulated in nitrogen and sulfur co-doped carbon matrix (MoO₂/MoS₂@NSC) by controllable sulfidation. MoO₂ and MoS₂ are coupled intimately at atomic level, forming the MoO₂/MoS₂ heterointerfaces with different distribution density. Strong electronic interactions are triggered at these MoO₂/MoS₂ heterointerfaces for enhancing electron transfer. In alkaline media, the optimal material exhibits outstanding hydrogen evolution reaction (HER) performances that significantly surpass carbon-covered MoS₂ nanorods counterpart (η₁₀: 156 mV vs 232 mV) and most of the MoS₂-based heterostructures reported recently. First-principles calculation deciphers that MoO₂/MoS₂ heterointerfaces greatly promote water dissociation and hydrogen atom adsorption via the O–Mo–S electronic bridges during HER process. Moreover, benefited from the high pseudocapacitance contribution, abundant “ion reservoir”-like channels, and low Na⁺ diffusion barrier appended by high-density MoO₂/MoS₂ heterointerfaces, the material delivers high specific capacity of 888 mAh g⁻¹, remarkable rate capability and cycling stability of 390 cycles at 0.1 A g⁻¹ as the anode of sodium ion battery. This work will undoubtedly light the way of interface density engineering for high-performance electrochemical energy conversion and storage systems.