Selective Hydrothermal Leaching of Aluminum from Al3YRh x (x = 0, 0.2, 0.5, 1.0) Intermetallic Compounds: The Effect of Rh Variants in Comparing the Catalytic CO Oxidation and CO-PROX Reactions

Abstract

Wealth from modern civilization and globalization accelerates natural resource extraction and damages the Earth's environment. Elevated mute assassin "carbon monoxide (CO)" levels impede aerobic life. We need to develop limiting technologies to overcome these constraints. Stern environmental agreements to reduce CO levels are significant. In this work, a hydrothermal leaching (HyTL) of Al₃Y-Rh _x (x = 0, 0.2, 0.5, 1.0) intermetallic compounds yields Y(OH)₃ products with well-distributed rhodium (Rh). The HyTL method and active Rh element improved HyTL Al₃Y-Rh_0.5 catalytic CO oxidation and the preferential oxidation of the CO (CO-PROX) performance. Metal-support interactions and HyTL Al₃Y-Rh_0.5 catalyst synergy produce oxygen vacancies, govern CO oxidation, and standardize oxygen mobility. This is essential to the synthesized catalyst's improved catalytic performance. All low-temperature instances of Rh have strong catalytic activity. This study advances CO catalytic oxidation and CO-PROX over the HyTL Al₃Y-Rh_0.5 catalyst, ensuring the aggregation-activation process. The findings support an understanding of low-temperature catalytic systems.

Scheme 1. Schematic Illustration of the KOH HyTL of Al₃Y-Rh_x Intermetallic Compounds Using CO Oxidation Catalytic Equipment

Figure 1

XRD patterns (a) before and (b) after HyTL of Al₃YRh_x.

Figure 2

FE-SEM images of (a–c) HyTL Al₃Y and (d,e) HyTL Al₃Y-Rh_x. (f) TEM image of HyTL Al₃Y-Rh_x. (g) The possible graphic illustration of the urchin-like crystal growth mechanism of Al₃Y-Rh_x is step-by-step.

Figure 3

Catalytic activity of CO oxidation at (a) HyTL Al₃Y-Rh_x (x = 0, 0.2, 0.5, 1.0) and CO-PROX at (b) HyTL Al₃YRh_x (x = 0, 0.2, 0.5, 1.0). (c) Schematic illustration of the Mars–van Krevelen mechanism of oxidation of CO.

Figure 4

XRD patterns of before and after CO oxidation and CO-PROX reactions of (a) HyTL Al₃YRh₀, (b) HyTL Al₃YRh_0.2, (c) HyTL Al₃YRh_0.5, and (d) HyTL Al₃YRh_1.0.