Metal leaching is a major issue in efficient production of γ-valerolactone (GVL) from levulinic acid (LA) under mild reaction conditions. In this study, Ag was added to Cu-supported γ-Al₂O₃ catalyst to suppress Cu leaching in the hydrogenation of LA into GVL. The CuAg/Al₂O₃ catalyst was reduced in situ during the reaction, and Cu leaching in the solution was significantly suppressed. The bimetallic catalyst without reduction pretreatment achieved approximately 100% yield to GVL and exhibited good reusability in nine consecutive cycles under mild reaction conditions of 180 °C and 1.4 MPa H₂ pressure in tetrahydrofuran (THF). The strong interplay in the geometric and electronic effects between Cu and Ag was verified through XPS, H₂-TPR, TEM, STEM/EDS, and XRD analyses. This paper extensively discussed the mechanism of Ag on preventing Cu leaching and the superiority of in situ reduction in solution over external reduction in gas.

在温和的反应条件下，金属浸出是从乙酰丙酸（LA）有效生产γ-戊内酯（GVL）的主要问题。在这项研究中，银加入到铜-支持的γ-Al ₂ ö ₃催化剂以抑制铜在LA的氢化成GVL浸出。反应期间就地还原了CuAg / Al ₂ O ₃催化剂，并且显着抑制了溶液中的Cu浸出。在未经还原的预处理的情况下，双金属催化剂在GVL的收率接近100％，并且在180°C和1.4 MPa H _2的温和反应条件下连续九个循环显示出良好的可重复使用性在四氢呋喃（THF）中的压力。通过XPS，H ₂ -TPR，TEM，STEM / EDS和XRD分析证实了Cu和Ag之间的几何和电子效应之间的强相互作用。本文广泛讨论了Ag防止Cu浸出的机理以及原位还原溶液比外部还原气体的优越性。