无机材料学报, 2023, 38 (1): 71, 网络出版: 2023-09-25
原位负载Pt-Co高指数晶面催化剂的制备及其电催化性能
水热法 Pt-Co催化剂 高指数晶面 原位生长 直接乙醇燃料电池 hydrothermal method Pt-Co catalyst high index crystal plane in-situ growth direct ethanol fuel cell
摘要
直接乙醇燃料电池(DEFC)具有燃料易得、绿色高效的优点, 得到了广泛的研究, 但是DEFC催化剂存在催化效率低、稳定性差的问题, 制约了其快速发展。本研究采用液相水热合成法, 以聚乙烯吡咯烷酮(PVP k-25)为分散剂和还原剂、甘氨酸为表面控制剂和共还原剂, 通过调控Pt-Co金属前驱体的摩尔比, 一步制备了XC-72R炭黑负载的Pt1Cox/C高指数晶面纳米催化剂, 实现了催化剂晶粒在碳载体上的原位生长。Pt1Co1/3/C纳米催化剂暴露的高指数晶面主要包括(410)、(510)和(610)晶面。在晶体生长过程中, Pt1Co1/3/C纳米催化剂晶粒由“类球体”转变立方块, 最终得到具有高指数晶面取向的内凹形貌。Pt1Co1/3/C高指数晶面纳米催化剂的电催化活性最高, 其电化学活性表面积为18.46 m2/g, 对乙醇氧化峰电流密度为48.70 mA/cm2, 稳态电流密度为8.29 mA/cm2, CO氧化峰的电位为0.610 V。这说明具有高指数晶面的催化剂表面存在的台阶、扭结等缺陷原子, 可增加活性位点, 进而显示出优异的电催化性能。本研究可为高指数晶面催化剂材料的开发及工业化应用提供理论依据。
Abstract
Direct ethanol fuel cell (DEFC) has been widely studied because of its advantages of easy fuel availability, green and high effiency. However, DEFC catalysts are still frustrated with low catalytic efficiency and poor catalyst stability, which restrict its rapid development. In this work, XC-72R carbon black-loaded Pt1Cox/C high-index crystalline nanocatalysts were prepared in one step by liquid-phase hydrothermal synthesis, using polyvinylpyrrolidone (PVP k-25) as dispersant and reducing agent, glycine as surface control agent and co-reducing agent, and modulating the molar ratio of Pt-Co metal precursors to achieve the in-situ growth of catalyst particles on carbon carriers. The exposed high index crystalline facets of the Pt1Co1/3/C nanocatalyst mainly consisted of (410), (510) and (610) crystalline facets. The growth pattern of the Pt1Co1/3/C nanocatalyst grains varied from 'sphere-like' to cubic, and eventually to concave with high index grain orientation. The Pt1Co1/3/C nanocatalyst with high index crystalline surface has the highest electrocatalytic activity with an electrochemically active surface area of 18.46 m2/g, a current density of 48.70 mA/cm2 for the ethanol oxidation peak, a steady state current density of 8.29 mA/cm2 and a potential of 0.610 V for the CO oxidation peak. This indicates that the defect atoms such as steps and kinks on the surface of the catalyst with high index crystal plane can increase the active sites, thus showing excellent electrocatalytic performance. This study may provide a theoretical basis for the development and industrial application of high index crystalline catalyst materials.
姚仪帅, 郭瑞华, 安胜利, 张捷宇, 周国治, 张国芳, 黄雅荣, 潘高飞. 原位负载Pt-Co高指数晶面催化剂的制备及其电催化性能[J]. 无机材料学报, 2023, 38(1): 71. Yishuai YAO, Ruihua GUO, Shengli AN, Jieyu ZHANG, Kuochih CHOU, Guofang ZHANG, Yarong HUANG, Gaofei PAN.