Preparations and Electrocatalytic Ethanol Properties of Palladium Intercalated Hydrotalcite
- 2021年第27卷 
高性能的电催化剂对直接燃料电池的商业化应用有着至关重要的作用,目前的阳极材料还存在活性低、易中毒、成本高等问题。本研究以层状双氢氧化物(layered double hydroxides, LDHs)为载体通过浸渍法制备了新型纳米钯(Pd)催化剂,并通过X射线衍射仪、扫描电子显微镜、电感耦合等离子体质谱仪、能谱仪、透射电子显微镜、循环伏安法测试、计时电流测试和电化学阻抗等方法对催化剂的结构和电催化性能进行了研究。结果表明,新制备的Pd/Mg-Al-LDHs仍然保持着LDHs的层状结构,循环伏安测试表明在碱性条件下,Pd/Mg-Al-LDHs比Pd/C有更好的电催化乙醇活性和抗中间产物中毒性能,且乙醇浓度、扫描速率和温度等因素对峰电流有着直接影响。计时电流测试表明在电催化乙醇的过程中Pd/Mg-Al-LDHs比Pd/C拥有更高的电催化活性和稳定性。电化学阻抗测试表明,Pd插层可显著改善Mg-Al-LDHs的导电性,并降低电催化过程中电荷转移阻力。High-performance electrocatalysts play a vital role in the commercial application of direct fuel cells. Current anode materials still have such problems as low activity, easy poisoning and high cost. In this study, a new type of nano- palladium (Pd) catalyst was prepared by dipping method using layered double hydroxides (LDHs) as the carrier. X-ray diffractometer, scanning electron microscope (SEM), inductively coupled plasma mass spectrometer (ICP-MS), energy spectrometer, transmission electron microscope (TEM), cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscope were used to analyze the structure and electrocatalytic performance of the catalyst. The results showed that the newly prepared Pd/Mg-Al-LDHs still maintained the layered structure of LDHs, and the metal Pd was evenly dispersed between the layers of hydrotalcite. Cyclic voltammetric curves showed that under alkaline conditions, the peak current density of Pd/Mg-Al-LDHs with 7% Pd in electrocatalytic ethanol was 36 mA·cm-2. The peak current density of commercial Pd/C in electrocatalytic ethanol was 30 mA·cm-2, and Pd/Mg-Al-LDHs exhibited better resistance to intermediate product poisoning. The factors including ethanol concentration, scanning rate and temperature were found to be effective, in particular, peak current had a direct effect. The chronoamperometric test revealed that Pd/Mg-Al-LDHs displayed higher electrocatalytic activity and stability toward ethanol than Pd/C, and the current density of Pd/Mg-Al-LDHs at 2000 s was 12 times to that of the commercial Pd/C. The electrochemical impedance data showed that Pd intercalation could significantly improve the conductivity of Mg-Al-LDHs and reduce the resistance to charge transfer during the electrocatalytic process.