Temperature-dependent highly active LaCaMgAl2O4 catalyst effect on carbon nanomaterial and hydrogen generation from polymethyl methacrylate plastic.

Abstract

The increasing accumulation of waste polymethyl methacrylate (PMMA) plastics presents a significant environmental challenge, while the demand for renewable energy sources continues to rise. Thermochemical recycling is a prospective technique for converting waste plastics into high-value chemicals, both economically and environmentally. In this work, the catalytic pyrolysis of waste PMMA plastics over LaCaMgAl₂O₄ nanosheets (NSs) catalyst is being investigated for its potential to produce hydrogen and carbon nanotubes (CNTs) in a two-stage fixed-bed reactor. The yield and purity of the gaseous products, as well as carbon deposition, concerning the effects of temperature during the catalysis process. Additionally, a small portion of LaCa was incorporated into the MgAl₂O₄ composite in the pre-catalysts under investigation. Analyzing the physicochemical properties of the carbon nanomaterials that form provides valuable insights into the workings of different catalysts. It's noteworthy that LaCaMgAl₂O₄ NSs showed such large yields of H₂ (82.71 vol% H₂) and CNTs (388 mg g^-1) at 750 °C. The LaCaMgAl₂O₄ NSs catalyst's impressive ability to produce CNTs and H₂ gas at high yields underscores its efficacy and potential for real-world catalytic pyrolysis applications. This study emphasizes the Nanocatalyst's potential for large-scale catalytic pyrolysis operations, providing a workable and efficient way of converting waste plastics into high-value products and renewable energy.