Optimal Co–Ir bimetallic catalysts supported on γ-Al2O3 for hydrogen generation from hydrous hydrazine

Abstract

A series of γ-Al2O3 supported bimetallic catalysts CoIrx/γ-Al2O3 was prepared by wet impregnation method followed by air calcination and hydrogen reduction. The catalysts were characterized by using AAS, FTIR, XRD, N2 physisorption, TPR, TPO, and SEM equipped with EDX which show the formation of Co–Ir nanoalloy particles well dispersed on γ-Al2O3 support. The catalytic activity was studied for the decomposition of hydrazine hydrate to generate hydrogen at room temperature and gaseous products were analyzed on mass spectrometer. High catalytic performance of bimetallic catalysts, CoIrx/γ-Al2O3, resulted due to the promoting effect of Ir metal. The optimum composition of CoIr0.081/γ-Al2O3 catalyst exhibited 100% H2 selectivity with TOF of 27.76 h−1. The catalytic activity was further tested at various temperatures to calculate kinetic parameters. The observed activation energy (40.8 kJ mol−1) for CoIr0.081/γ-Al2O3 catalyst reflected its better activity for hydrogen generation when compared to Co/γ-Al2O3 (51.9 kJ mol−1) alone. Hence, CoIr0.081/γ-Al2O3 catalyst is selected as an optimal composition for the hydrogen generation from hydrous hydrazine at room temperature.