Upcycling of Cr-Containing Sulfate Waste into Efficient FeCrO3/Fe2O3 Catalysts for CO2 Hydrogenation Reaction

Upcycling Cr-containing sulfate waste into catalysts for CO2hydrogenation reaction benefits both pollution mitigation and economic sustainability. In this study, FeCrO3/Fe2O3catalysts were successfully prepared by a simple hydrothermal method using Cr-containing sodium sulfate (Cr-SS) as a Cr source for efficient conversion and stable treatment of Cr. The removal rate of Cr in Cr-SS can reach 99.9% at the optimized hydrothermal conditions. When the synthesized catalysts were activated and used for the CO2hydrogenation reaction, a 50% increase in CO2conversion was achieved compared with the catalyst prepared by impregnation with a comparable amount of Cr. According to the extraction and risk assessment code (RAC) of the Reference Office of the European Community Bureau (BCR), the synthesized FeCrO3/Fe2O3is risk-free. This work not only realizes the detoxification of the Cr-SS but transfers Cr into stable FeCrO3for application in a catalytic field, which provides a strategy for the harmless disposal and resource utilization of Cr-containing hazardous waste.