Nano-nickel catalytic dehydrogenation of ammonia borane

Abstract

The complex chemical hydride, ammonia borane (NH3BH3, AB) is a hydrogen rich compound. It is a promising hydrogen source for applications using proton exchange membrane fuel cells (PEMFCs) due to hydrogen content. It has reasonably lower operating temperatures compared with other solid-state hydriding materials. At present, AB is an expensive disposable source which in its pure form releases 1 mol of hydrogen at around 110 °C. This temperature is much higher than the operating temperature of PEMFC (~80 °C). At the operating temperatures of the fuel cell, the slow kinetics of pure AB is a deterrent which provides enough scope for experimentation. The paper is the result of experimental thermolysis effort by using nano-nickel as a catalyst with pure AB. The neat and catalyzed AB isothermal decomposition and kinetic behavior are illustrated through the experimental results obtained under various conditions. The focus of experimentation is to increase the rate and extent of release of hydrogen at lower temperatures. The experimental results indicated that the use of nickel as catalyst reduced the induction period with significant improvement in hydrogen release compared with neat AB.