A nanoporous Ni(OH) 2 interlinked Co 3 O 4 heterojunction: a novel approach to chromium( vi ) detection

nanocrystals, forming a well-integrated interface that enables strong synergistic redox coupling and rapid electron transport across the junction. The nanoporous framework significantly increases the electrochemically active surface area offering abundant catalytically active sites and facilitates improved transport of electrolytes. Simultaneously, the heterojunction ensures continuous conductive pathways, thereby minimizing charge-transfer resistance and enhancing overall electron mobility. The combined structural and electronic advantages translate into markedly improved sensitivity, catalytic activity, and operational stability for enzymatic Cr(vi) detection with a limit of detection (LOD) of 39 nM. Overall, the results underscore the significant role of heterojunction engineering in enhancing the performance of metal hydroxide-oxide materials for advanced environmental sensing applications.