Ru Dispersed on Oxygen-Defect-Rich CeO₂ Nanorods for Ammonia Decomposition

Abstract

Ammonia is recognized as the best carrier for hydrogen storage and transportation. Nanomaterial catalysts have eminent catalytic activity for ammonia decomposition. However, the preparation of low-loading, high-activity noble metal atomically dispersed nanometer ammonia decomposition catalysts and their reaction mechanisms remain obscure. In this work, we report the synthesis of a stable ruthenium (Ru) atomically dispersed catalyst with oxygen-rich defects achieved through hydrogen etching of the support CeO 2 NR nanorods. The oxygen defects result in the catalyst exhibiting a favorable low-temperature catalytic activity and an exceedingly high atom utilization rate for ammonia decomposition. The hydrogen production rate from ammonia decomposition per unit mass of Ru is as high as 2446 mmol H 2 g Ru −1 min −1 at 1 bar, 450 °C, and gas hour space velocity = 12,000 mL g cat −1 h −1 . In this case, the highly dispersed Ru provided enough active sites, while the oxygen defects of the catalyst enhanced the electron transfer tunnel between Ru and the nanorod support under a Schottky contact model. The detailed mechanism of oxygen defects for improving the catalytic performance of ammonia decomposition was studied by DFT modeling. Thus, this work provides a promising strategy to improve the catalytic efficiency of an atomically dispersed Ru nanocatalyst.