Simultaneous production of high-purity hydrogen and carbon from waste organic solvents by liquid-phase plasma cracking over perovskite composite catalysts

Abstract

In this study, a method for purifying waste volatile organic compound solvents through a simple distillation process, followed by the generation of hydrogen and carbon via liquid-plasma cracking is proposed. In addition, a novel PrBiFeO₃ perovskite composite with excellent visible light sensitivity is introduced to enhance the efficiency of this reaction. The waste organic solvents are converted into refined organic solvents through distillation. During this process, hydrogen gas and carbon particles are generated. To improve the activity of the plasma decomposition, titanate-based perovskites (CaTiO₃, SrTiO₃, NiTiO₃) and ferrite-based perovskites (PrFeO₃, PrBiFeO₃) were synthesized and employed as catalysts. To achieve a catalyst with better optical absorption and a lower band gap energy for visible light, a newly prepared PrBiFeO₃ perovskite was utilized. The investigation into the optical properties of these perovskites revealed a high sensitivity to visible light. When these catalysts were applied to the liquid-phase plasma cracking of organic solvents, the ferrite-based perovskite catalysts demonstrated higher reaction activity. The highest rate of hydrogen evolution and carbon yield were obtained with the PrBiFeO₃ catalyst, achieving approximately 150 L/(g∙h) and 17.7 %, respectively. In this reaction system, sensitivity of the catalyst to visible light was correlated with increased reaction activity. The hydrogen exhibited high purity, while the carbon was also of high purity, characterized by small particle size and a large specific surface area.