铅修饰的纳米多孔铂催化剂对甲酸氧化的电活性

doi:10.13208/j.electrochem.170707

摘要/Abstract

摘要：

用合适金属修饰的铂催化剂能够显著增强其对甲酸氧化的电活性. 本文以水热法制备了钛负载的纳米多孔铂电极（nanoPt/Ti），然后采用循环伏安法，通过扫描不同的周数（n），用适量的铅对nanoPt/Ti电极进行修饰，得到一种新型的铅修饰的纳米多孔铂电极（nanoPb_(n)-Pt/Ti）. 采用循环伏安（CV）、计时电流和计时电位法研究其对对甲酸氧化的电活性. CV结果显示nanoPt/Ti和nanoPb_(n)-Pt/Ti电极对甲酸氧化表现出较高的催化活性，并且nanoPb₍₂₀₎-Pt/Ti电极对甲酸氧化的起始电位为-0.06 V，相比nanoPt/Ti电极的起始电位（0.06 V），明显有所负移. 此外，nanoPb₍₂₀₎-Pt/Ti电极的第一个氧化峰电流密度为12.7 mA·cm^-2，远远大于nanoPt电极（4.4 mA·cm^-2）；计时电流显示在电位为0.1 V时，在0.5 mol·L^-1 H₂SO₄ + 1 mol·L^-1 HCOOH溶液中，nanoPb₍₂₀₎-Pt/Ti电极达到稳定时的电流为8.09 mA·cm^-2，是nanoPt电极的60倍，表明铅修饰的nanoPt/Ti对甲酸氧化的电活性急剧增加；在1.5 mA、2 mA、2.2 mA和2.5 mA下的计时电位结果表明，nanoPb₍₂₀₎-Pt/Ti电极上甲酸氧化过程表现出显著的电化学振荡，且和nanoPt/Ti电极相比，振荡现象能持续更长的时间，说明nanoPb₍₂₀₎-Pt/Ti电极具有更强的表面抗毒化能力.

关键词: 甲酸氧化；纳米多孔Pt, 纳米多孔Pb-Pt；电化学震荡

Abstract:

Platinum (Pt) catalysts modified by other suitable metals significantly enhance their electrochemical activities for formic acid oxidation. In this work, a titanium-supported nanoporous network platinum (nanoPt/Ti) electrode was prepared using a hydrothermal method. The as-prepared nanoPt/Ti electrode was modified with a certain amount of lead by using cyclic voltammetry for different scan cycle numbers (n), namely, n = 10, 15, 20 and 30, to synthesize the novel lead-modified nanoporous Pt (nanoPb_(n)-Pt/Ti) electrodes. Electro-oxidation of formic acid on these electrodes was studied with cyclic voltammetry (CV), chronoamperometry and chronopotentiometry in sulfuric acid solution. CV curves showed that both nanoPt/Ti and nanoPb_(n)-Pt/Ti electrodes displayed high electrocatalytic activities for formic acid oxidation, and the onset potential of formic acid oxidation on the nanoPb₍₂₀₎-Pt/Ti electrode was -0.06 V, which was more negative than that on the nanoPt/Ti electrode (0.06 V). In addition, the first oxidation peak current density on the nanoPb₍₂₀₎-Pt/Ti electrode was 12.7 mA·cm^-2, which was far larger than that on the nanoPt electrode (4.4 mA·cm^-2). Chronoamperommetric data at 0.1 V in 0.5 mol·L^-1 H₂SO₄ + 1 mol·L^-1 HCOOH suggested that the nanoPb₍₂₀₎-Pt/Ti electrode exhibited the stable current density of 8.09 mA·cm^-2 which was 60 times higher than the nanoPt electrode, indicating the dramatic enhancement of electroactivity on the lead-modified nanoPt/Ti electrode for formic acid oxidation with comparison to the nanoPt/Ti electrode. Chronopotentiometric responses on the electrode at 1.5 mA, 2 mA, 2.2 mA and 2.5 mA in 0.5 mol·L^-1 H₂SO₄ + 1 mol·L^-1 HCOOH revealed notable electrochemical oscillations which lasted longer time than those on the nanoPt/Ti electrode. It was demonstrated that the lead-modified nanoPb₍₂₀₎-Pt/Ti electrode presented the most significant enhancement on surface anti-poisoning ability.

Key words: formic acid oxidation, nanoporous Pt, nanoporous Pb-Pt, electrochemical oscillations

中图分类号:

O646

张媛媛，易清风，左葛琨琨，邹涛，刘小平，周秀林. 铅修饰的纳米多孔铂催化剂对甲酸氧化的电活性[J]. 电化学（中英文）, 2018, 24(3): 270-278.

Yuanyuan Zhang, Qingfeng Yi，Gekunkun Zuo, Tao Zou, Xiaoping Liu, Xiulin Zhou. Lead Modified Nanoporous Platinum Electro-Catalysts for Formic Acid Oxidation[J]. Journal of Electrochemistry, 2018, 24(3): 270-278.

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