Researchers at Australia’s have developed less expensive and more efficient catalysts for producing hydrogen from water-splitting. In a paper in Advanced Functional Materials, they reported introducing a low concentration of gold into Co(OH)₂ followed by electrodeposition of Ni(OH)₂ to yield a Co(OH)2‐Au‐Ni(OH)₂ composite active in overall water splitting.

This material exceeds the activity of Pt for the HER at current densities greater than 40 mA cm⁻² and is stable for both reactions for prolonged periods of electrolysis. In a two‐electrode configuration, current densities greater than 175 mA cm⁻² for overall water splitting could be readily achieved at an applied voltage of 1.90 V in a commercially relevant electrolyte of 6 m NaOH.

—Sultana et al.

Activity for hydrogen evolution or oxygen evolution can be achieved by tuning the gold content between 0.1 and 0.2 at%. Further, they noted, this approach may also be applicable to other metal hydroxide/metal nanomaterial composites.

What we have found is that we can use two earth-abundant cheaper alternatives—cobalt and nickel oxide with only a fraction of gold nanoparticles—to create a stable bi-functional catalyst to split water and produce hydrogen without emissions.

From an industry point of view, it makes a lot of sense to use one catalyst material instead of two different catalysts to produce hydrogen from water.

—Professor Anthony O’Mullane

Resources

• Ummul K. Sultana James D. Riches Anthony P. O’Mullane (2018) “Water Splitting: Gold Doping in a Layered Co‐Ni Hydroxide System via Galvanic Replacement for Overall Electrochemical Water Splitting” Advanced Functional Materials doi: 10.1002/adfm.201804361