Rapid microwave hydrogen release from MgH2 and other hydrides

A honeycomb ceramic monolith (HCM) that was coated with 0.54 wt% Ni (corresponding to 0.2 micron Ni thin layer) could be heated rapidly from room temperature to white glowing within 7 s under 1000 W microwaves. Energy efficiency to convert microwaves to heat via this Ni-coated HCM was estimated to be more than 90%. By loading metal hydride powder samples into the monolith channels, Ni-HCMs were demonstrated to release 100% hydrogen from MgH2 and other hydrides (NaBH4, NaAlH4, and LiH) under 200 W microwaves within 2–3 min. The new microwave/Ni-HCM method offers many advantages over the conventional electrical resistant or microwave heating methods on hydrides, including 1) very fast kinetics, 2) wide application range for various hydrides, 3) simple process with no ball-milling or catalyst addition, and 4) very high energy efficiency.