Preparation, characterization and catalytic performance of Cu nanowire catalyst for CO₂ hydrogenation

Abstract

Pure Cu nanowires as catalyst were prepared by electrochemical deposition and were used in CO₂ hydrogenation to methanol. The active sites of the Cu based catalyst were discussed. The performance and structural development of the catalyst were observed during CO₂ hydrogenation. A mechanism for the deactivation of the catalyst was discussed. The key factors that affect the deactivation of the catalyst were found. Cu nanowire sample was characterized by SEM, EDS, XRD, and BET. The results show that Cu nanowires have very high sintering resistance and catalytic stability. This helps to develop high performance catalysts. The changes in the grain size, SEM morphology and catalytic properties of the sample during CO₂ hydrogenation show that the migration of the Cu atoms on the surface of the Cu nanowires can occur. Continuous migration of Cu atoms and sintering of Cu grains can lead to flow blockage in gas channels. The gas channel flow blockage or the sintering of Cu grains can lead to deactivation of the catalyst. However, the shape of catalytic performance curve indicates that the main reason for the deactivation of the catalyst is the gas channel flow blockage.

摘要

采用电化学沉积方法制备纯Cu 纳米线催化剂,并首次将其用于CO₂ 加氢合成甲醇反应,探讨 Cu 基催化剂的活性位,这有助于催化剂活性位的研究。观察CO₂ 加氢过程中催化剂的性能和结构变 化,探讨催化剂的失活机理,找出影响催化剂失活的关键因素,这有利于提高催化剂的应用性能。通 过SEM、EDS、XRD 和BET 等检测手段对Cu 纳米线样品进行表征。结果发现,Cu 纳米线具有非常 高的抗烧结性能和催化稳定性,这有助于研制高性能催化剂CO₂ 加氢过程中样品的晶粒尺寸、SEM 形貌和催化性能的变化情况表明,Cu 纳米线表面的Cu 原子可能发生迁移。Cu 原子不断的迁移和Cu 晶粒不断的烧结可能导致气体通道堵塞。气体通道堵塞或Cu 晶粒烧结均可能导致催化剂失活。然而, 催化性能曲线的形状表明,该催化剂失活的主要原因是气体通道堵塞。