Interfaces and Oxygen Vacancies-Enriched Catalysts Derived from Cu-Mn-Al Hydrotalcite towards High-Efficient Water–Gas Shift Reaction

• Published in: Molecules
• Main Authors: Hanci Li, Zhenyi Xiao, Pei Liu, Hairu Wang, Jiajun Geng, Huibin Lei, Ou Zhuo
• Format: Article
• Language: English
• Published: MDPI AG 2023-02-01
• Subjects: water–gas shift; hydrotalcite; oxygen vacancies; interface; hydrogen
• Online Access: https://www.mdpi.com/1420-3049/28/4/1522

The water–gas shift (WGS) reaction is an important process in the hydrogen industry, and its catalysts are of vital importance for this process. However, it is still a great challenge to develop catalysts with both high activity and high stability. Herein, a series of high-purity Cu-Mn-Al hydrotalcites with high Cu content have been prepared, and the WGS performance of the Cu-Mn-Al catalysts derived from these hydrotalcites have been studied. The results show that the Cu-Mn-Al catalysts have both outstanding catalytic activity and excellent stability. The optimized Cu-Mn-Al catalyst has displayed a superior reaction rate of 42.6 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mrow><mi mathvariant="sans-serif">μ</mi><mi>mol</mi></mrow></mrow><mrow><mi>CO</mi></mrow><mrow><mrow><mo>−</mo><mn>1</mn></mrow></mrow></msubsup><mo>⋅</mo><msubsup><mi mathvariant="normal">g</mi><mrow><mi>cat</mi></mrow><mrow><mrow><mo>−</mo><mn>1</mn></mrow></mrow></msubsup><mo>⋅</mo><msup><mi mathvariant="normal">s</mi><mrow><mrow><mo>−</mo><mn>1</mn></mrow></mrow></msup></mrow></semantics></math></inline-formula>, while the CO conversion was as high as 96.1% simultaneously. The outstanding catalytic activities of the Cu-Mn-Al catalysts could be ascribed to the enriched interfaces between Cu-containing particles and manganese oxide particles, and/or abundant oxygen vacancies. The excellent catalytic stability of the Cu-Mn-Al catalysts may be benefitting from the low valence state of the manganese of manganese oxides, because the low valence manganese oxides have good anti-sintering properties and can stabilize oxygen vacancies. This study provides an example for the construction of high-performance catalysts by using two-dimensional hydrotalcite materials as precursors.