Hydrogen Peroxide (H2O2) is used for pulp and paper bleaching, and manufacture of mild bleaches in laundry detergents. Small quantities of this material are naturally present in surface water, ground water, and the atmosphere. Factories produce industrial volumes with a process akin to reduction of oxygen. Scientists have found a cheaper way to produce hydrogen peroxide from batteries and air.
Using a Zinc-Air Battery to Produce Hydrogen Peroxide
Hydrogen peroxide is currently expensive, and energy intensive to produce, say researchers in their report from the Indian Institute of Science. This high production cost is due to the rare and precious metal catalysts used in the current manufacturing process.
The scientists have found what they believe is a better, cheaper way to produce H2O2 in future, that could also degrade some industrial pollutants. Their process involves a zinc-air battery, which produces hydrogen peroxide by controlled oxygen reduction.
A Quick Dive Into Zn-Air Batteries
Zinc-air batteries have zinc metal (Zn) negative electrodes that interact with air, and free oxygen (O) on the positive side. Their electrolyte is a water (H2O) based solution. Completing a reaction therefore involves all the constituents of hydrogen peroxide (H2O2).
H2O2 Is a Byproduct of Zn-Air Chemistry
When a zinc-air battery discharges naturally and releases its energy, the oxygen in the air reduces, yielding hydrogen peroxide (H2O2), “The strategy here is to control the extent of the oxygen reduction reaction,” the team leader explains. “If you don’t control it at some level, then it will just go and form water.”
“The secret to producing hydrogen peroxide from batteries this way, he continues, “is to use specific catalysts. We are using a metal-free catalyst based on carbon in this instance.”
Their metal-free catalyst selectively drives the reaction to producing hydrogen peroxide (H2O2), and not water (H2O) which would otherwise have been the case.
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