Upcycling Waste Etchant into a Doped-Cu₂O Electrocatalyst for Efficient Acetoxime Synthesis from Nitrate and Acetone

The electronics industry generates substantial quantities of waste etchant, which is a hazardous stream rich in heavy metals. Conventional recycling techniques typically produce low-value materials, failing to recover the inherent chemical potential. This study presents an upcycling strategy that converts copper from hazardous waste etchant directly into a highly active (Pb,Mn)-doped Cu₂O electrocatalyst. This catalyst exhibits exceptional activity for C-N coupling between nitrate pollutant and biomass-derived acetone to produce acetoxime, a valuable chemical, with 97.94% selectivity. Advanced spectroscopic techniques and density functional theory calculations reveal that such high activity originates from the synergistic effect of Pb/Mn-doping and oxygen vacancies in the catalyst, which facilitates the formation of the *NH₂OH reaction intermediate via an ^•H-mediated hydrogenation process. Techno-economic analysis confirms a substantial profit of over $1500 per ton of acetoxime produced. The general applicability of this methodology is demonstrated by its successful extension to 31 distinct industrial waste sources. This work establishes a waste-to-wealth paradigm, offering a sustainable route for electronic waste valorization and the advancement of green chemical synthesis.