The ability of plastics to consume CO2 captured in industries while being pyrolyzed is extremely valuable. In this paper, the gasification and carbon fixation of polypropylene (PP) and polycarbonate (PC) during pyrolysis in a CO2 atmosphere at different temperatures and reaction times were investigated. At the same time, other plastics are pyrolyzed in the CO2 environment to compare the carbon fixation capacity of the plastics, including polylactic acid plastic and polystyrene plastic. The results showed that after a 30-min reaction time at 750 °C, the carbon conversion efficiency (CE) of PP plastic and PC plastic reaches 45.1% and 32%, respectively. When the temperature is 600 °C, PP plastic can fix carbon, and the longer the reaction time, the greater the effect of temperature. Furthermore, when PC plastic and PP plastic are copyrolyzed, the presence of PC plastic will reduce the carbon fixation ability of PP plastic, and it was found that only plastic polymers with very little oxygen content were able to fix CO2 in the pyrolysis process. Pyrolysis of PP plastic and PC plastic also produces fused-ring aromatic compounds such as naphthalene and anthracene and carbon microspheres.

Copper bismuth oxide (CBO) is an emerging photocathode in photoelectrochemical (PEC) water splitting but exhibits limited performance due to the severe recombination of photogenerated charges at the semiconductor–liquid junction (SCLJ). For the first time, a set of operational spectroelectrochemical experiments including electrochemical impedance spectroscopy (EIS), transient photocurrent spectroscopy (TPS), and intensity-modulated photocurrent/voltage spectroscopy (IMVS, IMPS) are designed to investigate the charge dynamics at the SCLJ. It is indicated that there are dense surface states above the valence band of CBO, inducing the “Fermi level pinning” (FLP) effect at the SCLJ. The kinetic parameters speculated by IMVS and IMPS indicate the charge transfer efficiency of below 10% with even a bias of ∼0.7 V applied. TPS confirms the sluggish dynamics because of the charging behavior of the surface states. It is expected that this work would provide new connotations of charge dynamics at the SCLJ for the further optimization of CBO-based PEC systems.

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