Slag-based geopolymer microsphere-supported Cu: a low-cost and sustainable catalyst for CO2 hydrogenation†
Abstract
Recent studies on the exploration of sustainable approaches by utilizing large-scale waste materials as potential catalysts in the field of heterogeneous catalysis have attracted much attention. Using industrial waste as a catalyst or catalyst support has the advantages of being environmentally friendly and cost-effective. The reverse water gas shift (RWGS) reaction has been widely studied as an effective way to reduce CO2 emissions. In this work, we used NaOH-activated slag-based geopolymer microspheres (SGSs) as supports to prepare catalysts with different Cu loadings by a simple impregnation method. The results showed that a 10% Cu/SGS catalyst exhibited the best CO2 conversion performance. At a reaction temperature of 550 °C, the CO2 conversion and CO selectivity of the 10% Cu/SGS catalyst reached 48% and 96%, respectively. It was found that the high performance mainly results from the interaction between Cu and the SGS support and the adsorption and activation of CO2 by the basic sites on the SGS support. The findings regarding the performance of Cu/SGS catalysts and the associated reaction mechanism may significantly benefit further development of geopolymer support catalysts.