Facet-specific heterojunction in gold-decorated pyramidal silicon for electrochemical hydrogen peroxide sensing

•Large scale Si pyramidal electrodes with monolithic exposure of Si (111) can be prepared by selective alkaline etching.•Fabricated Au/Si (111) heterojunction is 195 times more sensitive to H2O2 than Au/Si (100) reflecting facet-dependent electrochemical properties.•Au/Si (111) heterojunction interface gives high sensitivity (171 μA mM−1 cm−2), wide linear range (0.01–55.55 mM), and low detection limit (1.24 μM).