碳纳米管负载的Pd-Ag-Sn催化剂对甲酸的电氧化

采用硼氢化钠还原的方法合成了碳纳米管负载的钯基纳米催化剂（Pd/CNT，Pd₇Ag₃/CNT，Pd₇Sn₂/CNT，Pd₇Ag₁Sn₂/CNT，Pd₇Ag₂Sn₂/CNT和Pd₇Ag₃Sn₂/CNT）。通过XRD，TEM和XPS对其进行了表征，结果表明，相比Pd/CNT和Pd-Ag（或Pd-Sn）催化剂的纳米颗粒，Pd-Ag-Sn催化剂展现出了更小的平均颗粒尺寸（2.3 nm）。此外，还通过循环伏安（CV）和计时电流法（CA）测试了这些催化剂对甲酸氧化的电活性，在酸碱介质中，Pd-Ag-Sn/CNT对甲酸氧化都表现出了更高的电流密度。其中，Pd₇Ag₂Sn₂/CNT催化剂在酸碱介质中的电流密度分别是108.8和211.3 mA·cm^-2，相应的Pd质量电流密度高达1 364和2 640 mA·mg^-1，远远高于商业Pd/C，表明Pd-Ag-Sn/CNT催化剂对甲酸氧化表现出了极好的电催化活性。

Carbon Nanotube-Supported Ternary Pd-Ag-Sn Catalysts for Formic Acid Electro-Oxidation

Carbon nanotube-supported Pd-based binary and ternary nanocatalysts (Pd/CNT, Pd₇Ag₃/CNT, Pd₇Sn₂/CNT, Pd₇Ag₁Sn₂/CNT, Pd₇Ag₂Sn₂/CNT and Pd₇Ag₃Sn₂/CNT) have been fabricated by the NaBH₄ reduction method. They have been characterized by using XRD, TEM and XPS techniques. The ternary Pd-Ag-Sn nanoparticles exhibit a smaller average particle size of ca. 2.3 nm compared to Pd/CNT and binary Pd-Ag (or Pd-Sn) nanoparticles. The electrocatalytic activity of these catalysts towards formic acid oxidation in both H₂SO₄ and NaOH solutions has been investigated using cyclic voltammetry (CV) and chronoamperometry (CA). In both acidic and alkaline media, the ternary Pd-Ag-Sn/CNT catalysts present higher anodic current density for formic acid oxidation than Pd/CNT and binary PdAg/CNT or PdSn/CNT catalysts. Among the prepared catalysts, the Pd₇Ag₂Sn₂/CNT catalyst displays the highest HCOOH oxidation current density of 108.8 mA·cm^-2 in 0.5 mol·L^-1 H₂SO₄ solution or 211.3 mA·cm^-2 in 1 mol·L^-1 NaOH solution, corresponding to the Pd mass current density of 1 364 or 2 640 mA·mg^-1, respectively. These currents are extremely larger than those obtained from the commercial Pd/C. Results exhibit the excellent electrocatalytic activity of the ternary Pd₇Ag₂Sn₂/CNT catalyst towards formic acid oxidation.