Hydrogen production via ammonia decomposition catalyzed by Ni/M-Mo-N (M 1/4 Ni, Co) bimetallic nitrides

This study demonstrates the significant improvement in NH3 decomposition using Ni-decorated M-Mo-N-based catalysts (M = Co and Ni) compared with conventional catalysts. Catalysts are prepared using a mixture of the corresponding metal salts and hexamethylenetetramine, and the impregnation method is used to decorate the Ni-particles on the catalysts. Among all the samples, 10 wt% Ni-decorated Co3Mo3N exhibits the highest NH3 conversion rate (71%) at 500 degrees C, and the performance remains stable for 30 h of long-term testing. According to the gas chromatography measurements, the H2/N2 ratio is approximately 3 in all cases, which is consistent with the theoretical value. X-ray photoelectron spectroscopy results show that Co3Mo3N possesses the highest NH3 con-version efficiency because of the weaker binding energy of Mo-N. Furthermore, Co3Mo3N exhibits a stronger Lewis acidity and higher NH3 decomposition, which is attributed to the easy breaking of the N-H bond on the Co3Mo3N surface.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study demonstrates the significant improvement in NH3 decomposition using Ni-decorated M-Mo-N-based catalysts, with 10 wt% Ni-decorated Co3Mo3N showing the highest conversion rate and stability. The results indicate that Co3Mo3N has weaker Mo-N binding energy, stronger Lewis acidity, and higher NH3 decomposition capability.