(509br) Au Based Ni and Co Bimetallic Core-Shell Nanocatalysts for Room Temperature Selective Decomposition of Hydrous Hydrazine to Hydrogen

Hydrogen is a clean fuel which on burning produces only water as by product while releasing energy with no net negative impact on environment. However, the safe and efficient storage of hydrogen as compressed gas is the major hurdle, currently onsite production is the best alternative for fuel related applications. Various hydrogen storage materials were explored, where chemically bound hydrogen should be released on demand without supplying much energy. Liquid hydrogen storage materials are effective and safe. Among them hydrous hydrazine is of current interest. Bimetallic nanoparticles promote the selective decomposition of hydrous hydrazine compared to their monometallic counterparts. In spite of much progress with bimetallic catalyst there is limited attention for Au based bimetallic catalyst for catalytic decomposition of hydrous hydrazine. Nickel and Cobalt bimetallic catalysts with Au as core metal has been synthesized and demonstrated for hydrazine decomposition reaction for producing hydrogen. Gold-cobalt and gold nickel bimetallic system belonging to the class of strained structures with high lattice mismatch of approximately 14% are demonstrated for synergistic effects for the selective decomposition of hydrous hydrazine to H₂ with N₂. Monometallic cobalt nanoparticle exhibited the catalytic activity at room temperature without being selective; however it improves drastically in bimetallic combinations of Au@Co at room temperature. At a particular shell thickness (Au@Co 1:0.5) catalyst gave good activity and 100% selectivity towards hydrogen along with nitrogen in hydrazine decomposition reaction. In case of Au@Ni, monometallic Ni and Au catalyst is inactive at room temperature even in presence of NaOH, while combination of both Au and Ni allows the hydrazine decomposition reaction to occur at room temperature with NaOH. These results reveal that by choosing proper bimetallic combinations synergistic catalysis can be achieved where selectivity can be tuned based on the metal compositions which can open a new perspective in hydrogen generation.