Dong et al. [106] found that agglomeration of CuO particles were formed when the percentage of Cu was higher than 43% in CuPS preparation. They claimed that a maximal loading of Cu for phyllosilicate is at 39%, corresponding to the Cu–Si molar ratio of approximately 0.75. The favorable weight loading of Cu to synthesize CuPS-cats is in line with the content of Cu in chrysocolla (Cu2Si2O5(OH)2). However, the relation of Cu loading and activity of CuPS-cat varies in different systems. Li et al. [108] found that 10% of Cu showed the best performance for hydrogenation of ethylene carbonate (EC) to EG. Jiang et al. [111] reported the 20% CuPS-cats could maximize the conversion of adipic acid (AA) and the yield of its hydrogenated product, i.e., 1,6-hexanediol (HDOL). For the conversion of furfural (FFAL) to 2-methyl furan, 25% of Cu was reported to be appropriate [106]. Much remains to be learned about the correlation between a proper Cu content and different hydrogenation reactions.