This technology showcases the fabrication of self-supported cobalt oxide-based catalyst beads by a novel gel-casting technique. The cobalt oxide-based catalysts are formulated to accelerate the hydrolysis of sodium borohydride (NaBH4) for the production of high purity hydrogen gas, which can be used as a fuel source for portable proton exchange membrane fuel cells (PEMFC). Cobalt oxide-based catalyst beads are promising alternatives to those of precious metals such as ruthenium (Ru) and rhodium (Rh), owing to their high reactivity, cost effectiveness, high durability (at least 10 times more durable in lifespan than the commercial Ru deposited catalyst beads) and recyclability.
The cobalt oxide based catalysts are developed by mixing the metal oxide with at least two monomers and a dispersant to produce a slurry which is then gel casted and sintered to form the final product. The developed catalysts display higher catalytic effect on the hydrolysis of NaBH4 than that of other metal based ones. They are expected to exceed hydrogen generation rate of 1 L min-1 g-1 for high-efficiency hydrogen generation system applications at 80oC. The parameters associated to the scaling up production of catalyst beads and the hydrolysis efficiency of sodium borohydride has also been optimised. The attached diagram shows the morphologies of cobalt oxide-based catalysts sintered at different temperature: (a) 1100oC, (c) 1200oC and (e) 1300oC before and (b) 1100oC, (d) 1200oC and (e) 1300oC after catalytic reaction measurement in 25% NaBH4 + 1% NaOH solution at 80oC.
The catalyst can be incorporated into products that are able to utilise hydrogen gas from the hydrolysis of NaBH4. These include 2-5W handheld micro-fuel cell chargers targeting consumer electronics and recreational power, 5W-100W portable power systems targeting recreational outdoors, emergency preparedness and disaster relief, and 200-3000W power systems targeting long duration electric flight (unmanned reconnaissance/surveillance aircraft).
Hydrogen fuel cells are still quite unaffordable and absence of infrastructure makes it inconvenient for adoption. Use of expensive catalysts is one of the major reasons for this. Hydrogen fuel cells would be required to be available at an installation cost of $1,500 or less per KW, in order to make a mark in the stationary power market. Presently the cost is in the range of $4,000 and above per kilowatt and about $50 to $100 to fill up a car. In the automobile sector, the required cost would be $60 - $100 per KW. Ongoing research and innovative technologies is expected to boost hydrogen fuel cell market from $336 million in 2009 to $716 million in 2013. The figures were expected to grow to $1.22 billion by 2014 including stationary, transport, and other applications.
Source: Frost & Sullivan