German team doubles activity of water electrolysis catalysts for H2 production with monolayer of copper on platinum
10 March 2016
A team from the Ruhr-Universität Bochum, Technische Universität München and Universiteit Leiden has doubled the catalytic activity of electrodes for water electrolysis by applying a monolayer of copper the platinum electrodes. The resulting electrodes are the most active electrocatalysts ever reported for the HER (hydrogen evolution reaction) in acidic media under comparable conditions, to the best of their knowledge, wrote the authors in an open-access paper in the journal Nature Communications.
Only about 4% of global hydrogen production is via water electrolysis, according to a 2012 analysis (Bičáková and Straka). The main impediments to a wider commercialization are the high energy losses in electrolyzers due to the insufficient activity of state-of-the-art electrodes.
Modern polymer electrolyte membrane (PEM) electrolyzers thus require larger platinum loadings (~0.5–1.0 mg cm-2) than those in PEM fuel cell anodes and cathodes combined (~0.5 mg cm-2).
Thus, the German team suggested, catalyst optimization would help in substantially reducing the costs for hydrogen production using this technology.
Here we show that incorporating (sub)monolayer amounts of copper (Cu) to platinum (Pt) enhances the catalytic activity ~2 times at low overpotentials, surpassing the highest HER-specific activities reported under similar conditions. These results are rationalized in terms of a structure-sensitive analysis of hydrogen adsorption on Pt- and Cu-modified Pt surfaces that also explains why polycrystalline Pt is more active than Pt(111) towards the HER.
—Tymoczko et al.
The team headed by Prof. Dr. Aliaksandr Bandarenka from the Department of Physics of Energy Conversion and Storage in Munich and Prof. Dr. Wolfgang Schuhmann from the Center for Electrochemical Sciences in Bochum has calculated how strongly intermediates must adhere to the electrodes to most efficiently facilitate the reaction. The analysis revealed that traditional electrodes from platinum, rhodium and palladium bind the intermediates a bit too strongly.
The researchers modified the properties of the platinum catalyst surface by applying a layer of copper atoms. With this additional layer, reaction intermediates could desorb a bit more easily from the catalyst surface. Positioning copper atoms into the subsurface layer of platinum weakens the surface binding of adsorbed H-intermediates, providing the two-fold activity increase.The group observed another useful side effect: the copper layer extended the service life of the electrodes, for example by rendering them more corrosion-resistant.
In addition, the research on this reaction allows us to test, how well we can design catalyst surfaces by precisely positioning different metal atoms—knowledge many other catalytic processes might benefit from.
—Aliaksandr Bandarenka
Resources
J. Tymoczko, F. Calle-Vallejo, W. Schuhmann, A. S. Bandarenka (2016) “Making the hydrogen evolution reaction in polymer electrolyte membrane electrolyzers even faster,” Nature Communications doi: 10.1038/NCOMMS10990
Bičáková, O. & Straka, P. (2012) “Production of hydrogen from renewable resources and its effectiveness,” Int. J. Hydrogen Energy 37, 11563–11578 doi: 10.1016/j.ijhydene.2012.05.047
A two-fold activity increase for electrolisers' anodes (and possibly for Fuel Cells) would be a win-win change for FCs, FCEVs and clean H2 stations?
Let's fine tune it a mass produce ASAP.
Posted by: HarveyD | 10 March 2016 at 02:10 PM
H2/O2 production at fueling stations can be done with renewable energy contracts. The O2 can be sold for medical purposes to offset the costs.
Posted by: SJC | 10 March 2016 at 04:23 PM
What they are not telling you is the efficiency. OK, the catalyst is more effective or there is less platinum required and it is research that may lead to worthwhile future results. However, you will still be putting in considerably more electric energy than the energy that the hydrogen contains. This is a fools game to believe that this is going to somehow make a greener world. Just put the electric power in the grid and burn less coal or gas or peat (which has to be the worst fuel available but some groups consider it a renewable energy source).
Posted by: sd | 10 March 2016 at 07:34 PM
As far as electrolytic production of H2 makes any sense at all, I could imagine that 3-D electrodes would be even more efficient.
It would be interesting to compare the results of a copper foam electrode in cylindrical form coated with an atomic layer of platinum and an atomic layer of copper on top of the platinum layer with the present electrode.
Posted by: yoatmon | 11 March 2016 at 09:11 AM
By 2025/2030 electrolizers will be more efficient and much cheaper to mass produce in various shapes and sizes.
Coupled with low pressure SS H2 higher density storage, future H2 stations will be much smaller and be built at much lower cost. A typical H2 station and distributors could eventually be fitted into a standard 20 to 40-ft container.
BEVs will also continue to progress but current anti-FCEV posters will be surprised?
Posted by: HarveyD | 15 March 2016 at 10:56 AM