Evolution of Co x Ni y Alloy Electronic Structure Buffered by Carbon Nanolayer to Tune Selective Generation of Reactive Oxygen Species

Generation of non-radical reactive oxygen species (ROS) via peroxymonosulfate (PMS) activation is desired to drive selective Fenton-like reactions and strongly affected by the electronic structure of catalyst. While the static structure-activity relationship of catalysts is well explored, how the evolution of electronic structure dynamically affects the ROS generation remains poorly understood. This study fabricated carbon nanolayer-supported Co_xNi_y alloys (Co_xNi_y@CNT) with preset atomic Ni/Co ratio (x/y = 1:3, 2:2, 3:1) to probe the dynamic evolution of electronic structure and its subsequent role for the generation of non-radical ROS. During catalytic PMS activation, the paired electrons of O 2p in PMS fill the corresponding hybrid orbitals of Co to form coordinative Co-O endowed with paired/unpaired electrons. The carbon nanolayer support, as in situ formed with controllable lattice distance, exhibits the unique electron buffering effect to replenish electron to Co₁Ni₃ or accept electron from Co₃Ni₁, thereby driving selective generation of surface PMS* or free ¹O₂ respectively. Further, the specific reaction preferences of PMS^* and ¹O₂ toward different organic contaminants were elucidated, and a combined process integrating both alloys was proposed to efficiently treat actual hospital wastewater. Overall, this study offers a molecule-level design of bimetallic alloys with tunable electronic structure for sustainable water purification.