Low dimensional electrocatalytic heterostructures have recently attracted significant attention in the catalysis community due to their highly tuneable interfaces and exciting electronic features, opening up new possibilities for effective nanometric control of both the charge carriers and energetic states of several intermediate catalytic species. In-depth understanding of electrocatalytic routes at the interface between two or more low-dimensional nanostructures has triggered the development of heterostructure nanocatalysts with extraordinary properties for water splitting reactions, NRR and CO₂RR. This tutorial review provides an overview of the most recent advances in synthetic strategies for 0D–1D, 0D–2D, and 2D–2D nanoheterostructures, discussing key aspects of their electrocatalytic performances from experimental and computational perspectives as well as their applications towards the development of overall water splitting and Zn–air battery devices.

Sodium rhodizonate was used as a bifunctional reducing as well as stabilizing agent for the single step synthesis of gold (Au), silver (Ag), platinum (Pt), and palladium (Pd) nanoparticles (NPs) in water. Transmission electron microscopy analysis revealed that Pt, Au, Ag, and PdNPs have average core diameters of about 2, 8, 26, and 39 nm, respectively. The ability of these nanoparticles towards the catalytic reduction of 4-nitrophenol (4-NP) with sodium borohydride (NaBH₄) and the dual-catalytic oxidation of formic acid followed by the reduction of methyl orange (MO) was studied. The apparent rate constants (k_app) of the catalytic reduction of 4-NP in the presence of Ag, Au, Pt, and PdNPs were calculated to be 2.1482, 1.1167, 1.088 × 10⁻¹, and 1.65 × 10⁻² min⁻¹, respectively. However, for the dual-catalytic oxidation of formic acid followed by the reduction of MO, the k_app values were calculated to be 4.145, 1.25 × 10⁻², 6.7 × 10⁻³, and 9.0 × 10⁻⁵ for the Pt, Pd, Au, and AgNPs, respectively.