Zinc based nanostructures are very promising material for pH sensing since they allow the realization of low-cost, sustainable, and high sensitivity electrodes. The pH sensitivity reported in literature for different ZnO nanostructures spreads from sub- to super-Nernstian, with the microscopic mechanism behind the H+ detection often unrevealed. In this work we synthesize by hydrothermal process and thermal annealing two zinc based nanowalls (NWLs) consisting of layered hydroxide zinc nitrate Zn5(OH)8(NO3)2·2H2O (as grown) and zinc oxide ZnO (annealed) phases, respectively. Scanning electron microscopy, micro Raman spectroscopy, X-ray photoemission spectroscopy were used to characterize the morphology and structure of NWLs. Electrochemical chronopotentiometric analysis in standard buffer solutions (pH 4 to 9) was used to study the response towards pH. Despite the two zinc based NWLs have the …