Unconventional trigonal PrNiO3 nanosheets for efficient electrocatalytic degradation of PET fibers

Electrocatalytic oxidation of ethylene glycol derived from polyethylene terephthalate (PET) fibers requires anodic catalysts that can sustain high current density while enabling efficient C–C bond cleavage through lattice-coupled redox processes. In Ni-based perovskite oxides, PrNiO 3 is uniquely positioned because its mixed-valence A-site allows strong Ni–O hybridization and defect-assisted charge transfer, yet in practice these advantages are constrained by crystallographic symmetry. The thermodynamically stable orthorhombic phase limits Ni–O covalency modulation and masks phase-dependent electronic effects, particularly in bulk architectures where active motifs remain poorly exposed. Here, this intrinsic phase limitation is overcome by kinetically stabilizing an unconventional, non-equilibrium trigonal phase of PrNiO 3 within a two-dimensional porous nanosheet framework using microwave shock synthesis. Electronic-structure and defect analyses reveal that the trigonal lattice enhances Ni–O electronic coupling and charge-buffering capability, directly accelerating anodic ethylene glycol oxidation kinetics. As a result, the phase-engineered PrNiO 3 achieves industrially relevant current densities near 100 mA cm −2 and sustains operation above 80 mA cm −2 with ∼90% formate efficiency in real PET fiber hydrolysates, outperforming conventional oxide catalysts. This work identifies non-equilibrium phase engineering in 2D perovskites as a route to unlock Pr-based nickelates for high-rate electrochemical upcycling of plastic textile waste.