Optimizing Compatibility between Oxidants and Catalysts for Heterogeneous Catalytic Water Purification

Metal oxides and carbon materials, which can be readily obtained from minerals and biomass, respectively, offer both performance and cost advantages and are the catalysts of choice for catalytic wastewater treatment applications. In this work, we explore the optimal compatibility between catalysts, with metal oxides and carbon materials as examples, and oxidants with peroxymonosulfate and peroxydisulfate (PMS and PDS) as representatives. Metal oxides catalyze PMS effectively and exhibit an efficiency 1-3 orders of magnitude higher than when catalyzing PDS. Conversely, carbon materials catalyze PDS much more effectively, with an efficiency 1-3 orders of magnitude higher than when catalyzing PMS. The scientific mechanism behind such a compatibility is found to be attributed to the polarity-based matching effect between valence bonds on the catalyst surface and the oxidant molecules, following the polarity principle of "similarity-intermiscibility" theory. Composite materials containing metal and carbon prepared according to this mechanism demonstrate robust performance for both PMS and PDS, consistent with the predictions and validating the rationality and expandability of the compatibility principle. This work provides guidance for catalyst selection in the application of persulfate-catalyzed water purification technology.