The overuse and ineffective management of plastics have led to significant environmental pollution. Catalytic upcycling into value-added chemicals has emerged as a promising solution. This review provides a comprehensive overview of recent advances in catalytic upcycling, focusing on the cleavage of chemical bonds such as carbon–carbon (C–C), carbon–oxygen (C–O), and carbon–hydrogen (C–H) in plastics. It systematically discusses plastics conversion via electrocatalysis, thermal catalysis, and photocatalysis. Additionally, it explores the conversion of plastics into value-added chemicals and functional polymers. The review also addresses the challenges in this field and aims to offer insights for developing sustainable and effective plastics upcycling technologies.

Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread attention. Herein we construct the well-defined Mn single-atom (MnSA) catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions (CO₂RR) and oxygen reduction reactions (ORR). MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90% at −0.9 V for CO₂RR and higher H₂O₂ yield from 0.1 to 0.6 V with excellent ORR activity. Density functional theory (DFT) calculations based on constant potential models were performed to study the mechanism of MnSA on CO₂RR. The thermodynamic energy barrier of CO₂RR is lowest at −0.9 V vs. reversible hydrogen electrode (RHE). Similar DFT calculations on the H₂O₂ yield of ORR showed that the H₂O₂ yield at 0.2 V was higher. This study provides a reasonable explanation for the role of electrode potential micro-environments.

The coupling of energy-saving small molecule conversion reactions and hydrogen evolution reaction (HER) in seawater electrolytes can reduce the energy consumption of seawater electrolysis and mitigate chlorine corrosion issues. However, the fabrication of efficient multifunctional catalysts for this promising technology is of great challenge. Herein, a heterostructured catalyst comprising CoP and Ni₂P on nickel foam (CoP/Ni₂P@NF) is reported for hydrazine oxidation (HzOR)-assisted alkaline seawater splitting. The coupling of CoP and Ni₂P optimizes the electronic structure of the active sites and endows excellent electrocatalytic performance for HzOR and HER. Impressively, the two-electrode HzOR-assisted alkaline seawater splitting (OHzS) cell based on the CoP/Ni₂P@NF required only 0.108 V to deliver 100 mA·cm⁻², much lower than 1.695 V for alkaline seawater electrolysis cells. Moreover, the OHzS cell exhibits satisfactory stability over 48 h at a high current density of 500 mA·cm⁻². Furthermore, the CoP/Ni₂P@NF heterostructured catalyst also efficiently catalyzed glucose oxidation, methanol oxidation, and urea oxidation in alkaline seawater electrolytes. This work paves a path for high-performance heterostructured catalyst preparation for energy-saving seawater electrolysis for H₂ production.