Electrons Make Shells, Photons Make Boxes: Unmasking Radiation Chemistry in Liquid‐Phase Imaging

ABSTRACT

Beam‐induced chemistry in liquid‐phase imaging is now recognized as a key factor in interpreting nanoscale redox processes, yet its consequences depend strongly on the irradiation modality, solvent chemistry, and reacting material system. Here, we compare how soft X‐ray and electron irradiation redirect the same galvanic replacement reaction between Cu ₂ O nanocubes and gold precursors. In this model system, soft X‐ray irradiation generates an oxidizing environment that promotes Cu ₂ O dissolution and hollow Au nanobox formation, whereas electron irradiation favors surface‐confined Au deposition and Au@Cu ₂ O core‐shell architectures. Adjusting the solution chemistry during LC‐TEM restores the hollowing pathway, showing that the local beam‐induced chemical environment controls the balance between deposition and dissolution. These findings demonstrate that, in Cu ₂ O‐Au galvanic replacement, the imaging beam is not merely a passive probe, but can actively reshape the observed nanoscale reaction pathway.