基于RuO2/TiO2-Ti3C2Tx碱性氢氧化催化剂的构建及高CO耐受性

Construction of RuO2/TiO2-Ti3C2Tx alkaline hydrogen oxidation catalyst and its high CO tolerance

  • 摘要: 碱性介质中较慢的氢氧化反应(Hydrogen oxide reaction, HOR)动力学极大地制约了氢氧燃料电池的发展。因此,开发高性能碱性HOR催化剂成为当前的主要任务。本文以二维Ti3C2Tx MXene作为催化载体,通过水热法一步合成RuO2/TiO2-Ti3C2Tx催化剂。首先通过TEM、XRD、XPS等手段详细表征了该催化剂的表面形貌和电子结构。然后通过电化学测试发现,在0.1 mol/L KOH电解液中,RuO2/TiO2-Ti3C2Tx表现出优异的HOR活性:在50 mV过电位(vs. RHE)下,RuO2/TiO2-Ti3C2Tx展示出高的几何交换电流密度( \textj_\text0 )为1.58 mA·cm−2,几何动力学电流密度( \textj_\textk )达到17.06 mA·cm−2,为Pt/C催化剂的4.77倍。此外,由于在水热反应过程中,部分Ti3C2Tx MXene催化载体表面氧化形成TiO2,使RuO2/TiO2-Ti3C2Tx在0.1%(1000 ppm) CO条件下连续运行5000 s,仍然表现出稳定的电催化HOR性能。得益于Ti3C2Tx MXene催化载体调控活性金属Ru的电子结构,进一步使活性位点减弱了氢吸附自由能(Hydrogen binding energy, HBE),增强了羟基吸附能(Hydroxyl binding energy, OHBE),RuO2/TiO2-Ti3C2Tx展示出优于商业Pt/C、Ru/C催化剂的HOR性能。本研究为设计开发高活性、高稳定性碱性HOR电催化剂提供了一种新的策略。

     

    Abstract: The slow kinetics of Hydrogen oxide reaction (HOR) in alkaline medium greatly restricts the development of hydrogen oxygen fuel cells. Therefore, the development of high-performance alkaline HOR catalysts has become the main task nowadays. RuO2/TiO2-Ti3C2Tx catalyst was synthesized in one step by hydrothermal method using two-dimensional Ti3C2Tx MXene as catalyst carrier. The surface morphology and electronic structure of the catalyst were first characterized in detail by TEM, XRD and XPS. Then, it was found by electrochemical test that RuO2/TiO2-Ti3C2Tx showed excellent HOR activity in 0.1 mol/L KOH electrolyte: At 50mV overpotential (vs. RHE), RuO2/TiO2-Ti3C2Tx exhibits a high geometric exchange current density (j0) of 1.58 mA·cm−2 and geometric dynamic current density (jk) of 17.06 mA·cm−2, which is 4.77 times that of Pt/C catalyst. In addition, in the hydrothermal reaction process, part of Ti3C2Tx MXene catalyzes the surface oxidation of the carrier to form TiO2, so that RuO2/TiO2-Ti3C2Tx can run continuously for 5000 s under the condition of 0.1%(1000 ppm) CO, and still show stable electrocatalytic HOR performance. The catalytic carrier Ti3C2Tx MXene regulates the electronic structure of the active metal Ru, which further reduces the Hydrogen binding energy (HBE) at the active site. RuO2/TiO2-Ti3C2Tx showed better HOR properties than commercial Pt/C and Ru/C catalysts with enhanced Hydroxyl binding energy (OHBE). This study provides a new strategy for the design and development of highly active and stable alkaline HOR electrocatalysts.

     

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