DENSITY FUNCTIONAL THEORY INVESTIGATION OF NI6, NI5PT, AND NI5RH CLUSTERS ON GRAPHENE FOR AMMONIA DECOMPOSITION AS A HYDROGEN CARRIER

• Main Author: Yusuf, Alfani
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86788
• Institution: Institut Teknologi Bandung

This study investigates the effectiveness of Ni6, Ni5Pt, and Ni5Rh metal cluster-based catalysts supported on graphene in the decomposition of ammonia into hydrogen (H2) and nitrogen (N2) using Density Functional Theory (DFT) through the VASP software. Ammonia (NH3) is considered a potential hydrogen carrier to meet the demand for clean energy. However, the separation of NH3 into H2 requires efficient, stable, and cost-effective catalysts. In this research, Ni metal clusters support on graphene with the addition of Pt and Rh atoms were examined to determine their effects on adsorption energy, activation energy, and the decomposition mechanism of NH3. The simulation results show that the Ni6/G catalyst exhibits the highest adsorption energy and reactivity for hydrogen dissociation, while Ni5Rh/G displays the lowest activation energy at the N2 recombination stage, making it more effective in reducing kinetic barriers. The addition of Pt and Rh strengthens the stability of the catalysts by lowering the adsorption energy of nitrogen and hydrogen, although it slightly weakens the initial ammonia adsorption. This study also confirms that nitrogen recombination is the rate-determining step, with the highest activation energy observed in the Ni6/G. Overall, the Ni5Rh/G catalyst demonstrates competitive performance as a more economical alternative to noble-metal-based catalysts such as Ru. This research provides valuable insights into the development of efficient nickel-based catalysts for ammonia decomposition, paving the way for more cost-effective hydrogen energy applications and supporting the transition to clean energy. Keywords: NH3 Decomposition, Hydrogen Utilitation, Density Functional Theory (DFT)