Improved Water Electrolysis by Catalytic Electrodes Discovered

by Tommy on 20/05/2017

Iron phosphate on nickel phosphide foam. This does make some sense.

However, this is not catalysis. Even natural pH does not evolve oxygen or hydrogen.

This is more properly described as catalytic electrolysis since it involves using DC electricity.

Highly active catalyst derived from a 3D foam of Fe(PO3)2/Ni2P for extremely efficient water oxidation, Haiqing Zhoua, Fang Yua, Jingying Sun, Ran Hea, Shuo Chena, Ching-Wu Chua and Zhifeng Rena, PNAS (21 April 2017), doi:10.1073/pnas.1701562114

The oxygen evolution reaction (OER) is a sluggish reaction with poor catalytic efficiency, which is one of the major bottlenecks in realizing water splitting, CO2 reduction, and rechargeable metal–air batteries. In particular, the commercial utilization of water electrolyzers requires an exceptional electrocatalyst that has the capacity of delivering ultra-high oxidative current densities above 500 mA/cm2 at an overpotential below 300 mV with long-term durability. Few catalysts can satisfy such strict criteria. Here we report a promising oxygen-evolving catalyst with superior catalytic performance and long-term durability; to the best of our knowledge, it is one of the most active OER catalysts reported thus far that satisfies the criteria for large-scale commercialization of water–alkali electrolyzers.

Commercial hydrogen production by electrocatalytic water splitting will benefit from the realization of more efficient and less expensive catalysts compared with noble metal catalysts, especially for the oxygen evolution reaction, which requires a current density of 500 mA/cm2 at an overpotential below 300 mV with long-term stability. Here we report a robust oxygen-evolving electrocatalyst consisting of ferrous metaphosphate on self-supported conductive nickel foam that is commercially available in large scale. We find that this catalyst, which may be associated with the in situ generated nickel–iron oxide/hydroxide and iron oxyhydroxide catalysts at the surface, yields current densities of 10 mA/cm2 at an overpotential of 177 mV, 500 mA/cm2 at only 265 mV, and 1,705 mA/cm2 at 300 mV, with high durability in alkaline electrolyte of 1 M KOH even after 10,000 cycles, representing activity enhancement by a factor of 49 in boosting water oxidation at 300 mV relative to the state-of-the-art IrO2 catalyst.

If we could make potassium phosphate somehow with this process that would be excellent.

Electrocatalytic production of potassium phosphate and nitrate was my original goal with this.

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