Preparation And Electro-catalytic Properties Of The Composite Electrode Of Nano Ni-B Based Alloy/TiO₂ Nanotube Arrays

Direct methanol fuel cell(DMFC) has attracted wide attention due to its high energy density, storage and transportation conveniently. But it is also facing high costs, deactivation and other issues. Pt or its alloys were used as catalysts of DMFC basically, but these shortcoming such as inadequate, high cost, easy to CO poisoning, inhibit the DMFC applications and large-scale development seriously. Therefore, the preparation of high activity and efficiency of non-precious materials insteading of Pt as a catalyst, is an important research direction of fuel cells, but also is the urgent requirement of expand the scope of DMFC. In this paper, Ti O2 nanotube arrays(TNTs) prepared by anodic oxidation as a template, plating and cyclic voltammetry electrodeposition prepare high catalytic performance of Ni-B/TNTs and Ni-Cu-B/TNTs alloy electrode. The research focus on the effect of the process factors(time, temperature, CTAB concentration, etc.) on the electrode morphology, composition, phase and electrochemical properties via XRD, FESEM, EDS and characterization methods such as cyclic voltammetry to. The results show as follow:1. Ni-B / TNTs alloy electrode is prepared by electroless plating with the surfactant CTAB has good catalytic activity for methanol electrooxidation in alkaline solution. Concentration of CTAB have a great impact on the morphology and electrochemical properties of surface particles of the electrode, when the concentration is 0.6g / L, the peak current density reachs to the maximum values of 31.1mA·cm-2. When the methanol concentration increases to 0.75 M, the peak current density reaches the maximum values of 58 mA·cm-2.The peak current density remains 56.7% of the initial value after 1300 cycles.2. The Ni-Cu-B/TNTs alloy electrode is prepared by electroless plating based on Ni-B alloy adding copper. With increasing electroless plating time and temperature,the peak current density increase at first,then decreased.When the condition is 30 min, 60?, the peak current density is maximum,155mA·cm-2. When the Cu / Ni ratio is 0.08, the best electro-catalytic oxidation activity of the electrode can be obtained. When the methanol concentration increases to 3 M, the peak current density reaches the maximum values of 180mA·cm-2. As the test temperature increasing, the peak current density first increases and then decreases, reaching a maximum at 30 ?. Compared with the Ni-B/TNTs electrode, Ni-Cu-B /TNTs electrode has a better cycle life.3. Ni-B/TNTs alloy is also prepared on TiO2 nanotube arrays electrode by cyclic voltammetry electrodeposition method. With the increasing of electrodeposition cycle, peak current density increases and then decreases. When electrodeposition scan rate is 0.02 V/s, the peak current density reaches the maximum, 32 mA · cm-2. The peak current density remains 39.0% of the initial value after 1300 cycles. Compared with Ni-B/TNTs electrode prepared by electroless plating, the Ni-B / TNTs electrode prepared by cyclic voltammetry electrodeposition has poor dispersibility and uniformity.