Correlation among preparation methods/conditions, physicochemical properties, and catalytic performance of Rh/hydroxyapatite catalysts in N2O decomposition

• Morphology controlled hydroxyapatite (HAP) samples were prepared hydrothermally.
• HAP supported Rh catalysts are efficient for N2O decomposition.
• The activity is correlated with the basicity and amount of adsorbed O2.

Three hydroxyapatite (HAP) supported rhodium catalysts (i.e., Rh/HAP-PEG-200, Rh/HAP-EDTA-200, and Rh/HAP-EDTA-100) were prepared by loading Rh(NO3)3 onto HAP supports prepared hydrothermally at 200 or 100 °C in the presence of PEG or EDTA additive, followed by calcination at 500 °C. For comparison, an additional Rh/HAP-normal catalyst was prepared using a conventional HAP support prepared by precipitation. Different preparation methods/conditions were found to influence the physicochemical properties (e.g., micro-morphology, basicity, concentration of surface hydroxyls, oxygen-desorption property) of HAP supports and/or Rh/HAP catalysts. The activities of these catalysts in N2O decomposition follow the sequence of Rh/HAP-PEG-200 > Rh/HAP-EDTA-200 ≈ Rh/HAP-normal > Rh/EDTA-100. The correlation among preparation methods/conditions, physicochemical properties, and catalytic performance of Rh/HAP catalysts was investigated in detail.

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