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Rice University researchers create dual-purpose edge-oriented MoS2 film for energy storage, hydrogen catalysis

A new material developed at Rice University based on molybdenum disulfide (MoS2) exposes as much of the edge as possible, making it efficient as both a catalyst for hydrogen production and for energy storage. Courtesy of the Tour Group. Click to enlarge.

The Rice lab of chemist James Tour has turned molybdenum disulfide’s two-dimensional form into a edge-oriented nanoporous film that can catalyze the production of hydrogen or be used for energy storage as part of a supercapacitor device.

The versatile chemical compound, classified as a dichalcogenide, is inert along its flat sides; however, previous studies determined the material’s edges are highly efficient catalysts for hydrogen evolution reaction (HER), a process used in fuel cells to pull hydrogen from water. Tour and his colleagues found a cost-effective way to create flexible films of the material that maximize the amount of exposed edge and have potential for a variety of energy-oriented applications. A paper on the research appears in the journal Advanced Materials.

Molybdenum disulfide isn’t quite as flat as graphene, the atom-thick form of pure carbon, because it contains both molybdenum and sulfur atoms. When viewed from above, it looks like graphene, with rows of ordered hexagons. Seen from the side, three distinct layers are revealed, with sulfur atoms in their own planes above and below the molybdenum.

This crystal structure creates a more robust edge, and the more edge, the better for catalytic reactions or storage, Tour said.

So much of chemistry occurs at the edges of materials. A two-dimensional material is like a sheet of paper: a large plain with very little edge. But our material is highly porous. What we see in the images are short, 5- to 6-nanometer planes and a lot of edge, as though the material had boreholes drilled all the way through.

—James Tour

The new film was created by Tour and lead authors Yang Yang, a postdoctoral researcher; Huilong Fei, a graduate student; and their colleagues. It catalyzes the separation of hydrogen from water when exposed to a current.

Its performance as a HER generator is as good as any molybdenum disulfide structure that has ever been seen, and it’s really easy to make.

—James Tour

While other researchers have proposed arrays of molybdenum disulfide sheets standing on edge, the Rice group took a different approach. First, they grew a porous molybdenum oxide film onto a molybdenum substrate through room-temperature anodization, an electrochemical process with many uses but traditionally employed to thicken natural oxide layers on metals.

The film was then exposed to sulfur vapor at 300 ˚C (572 ˚F) for one hour. This converted the material to molybdenum disulfide without damage to its nano-porous sponge-like structure, they reported.

The Rice lab also built supercapacitors with the films; in tests, they retained 90% of their capacity after 10,000 charge-discharge cycles and 83% after 20,000 cycles.

We see anodization as a route to materials for multiple platforms in the next generation of alternative energy devices. These could be fuel cells, supercapacitors and batteries. And we’ve demonstrated two of those three are possible with this new material.

—James Tour

Co-authors of the paper are Rice graduate students Gedeng Ruan and Changsheng Xiang. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of materials science and nanoengineering and of computer science.

The Peter M. and Ruth L. Nicholas Postdoctoral Fellowship of Rice’s Smalley Institute for Nanoscale Science and Technology and the Air Force Office of Scientific Research Multidisciplinary University Research program supported the research.


  • Yang, Y., Fei, H., Ruan, G., Xiang, C. and Tour, J. M. (2014), “Edge-Oriented MoS2 Nanoporous Films as Flexible Electrodes for Hydrogen Evolution Reactions and Supercapacitor Devices,” Adv. Mater. doi: 10.1002/adma.201402847



Im mix about this aricle. Can they do cheaper hydrogen from water then other current methods ?

Roger Pham

This is great.
Imagine a large solar PV installation covering the entire roof. Half of excess solar energy will be saved in low-cost SuperCap battery for night use, and the other half of excess solar energy will be used to make H2 for winter use, or for cloudy or rainy days. The Nat Gas piping system will be upgraded to handle H2 to and from home to underground H2 reservoir system for long-term storage.

The heat of electrolysis will be used for hot water heating, thus raising the efficiency of electrolysis to approaching 100%.
The waste heat of winter home Fuel Cell will be used for home heating, thus can raise the efficiency of H2 utilization to nearly 100%. If more heat than electricity will be needed on very cold days, perhaps the heat pump can convet some of the excess electricity into heat as well, boosting efficiency either way.

Very good round-trip efficiency for H2 energy storage, while avoiding the use of fossil fuels.


That's the idea, gor, although hydrogen is likely to be reasonably cheap anyway.
It is getting the price of the fuel cells down that is going to take work.

Would a plug in hybrid work for you instead?
There are lots of those coming.


Anyone know why they would want to combine a supercapacitor with hydrogen generation under water?
They don't seem to have much to do with each other to me.


New multi-platforms materials may be a way to reduce the cost of mass produced future batteries, super-caps, fuel cells and H2 converters?


Production of DHW from electrolysis is redundant if the PV has more than enough excess heat to provide it.

This seems to be typical of the schemes proposed by RE enthusiasts; there's usually a much more sensible and efficient scheme for doing the same thing that doesn't favor their proposed method.

Roger Pham

What if wind energy, hydroelectricity, and nuclear energy are the predominant energy sources instead of solar PV?
I envision an energy system wherein all energy sources are combined and are complementary to each others in order to minimize energy storage requirement and to maximize energy efficiency.
However, excess energy should be designed into the system, since energy deficiency will not be acceptable!
Excess energy from all these sources combined can be used to produce H2 in springs, summers, and falls while the waste heat from electrolysis can be used for hot water heating. The H2 will then be used for combined heat and power in winters, or to backup wind energy in rare events of windless and sunless days. Nuclear energy is used mainly as baseload, while hydroelectricity is used mainly for peakload, while wind enery is used whenever the wind blows.



I like your proposal to use (easily varied) hydro electricity mainly as peak load. Intermittent Solar and Wind energies should be used as close to 100% when available to reduce the size of storage units.


Wind and PV are good for time-insensitive loads, such as pumping water and making ice for later A/C consumption.  That is not how they're being used today.

I think that wind-powered rock-crushers would be great things to have, especially offshore.  They could reduce large pieces of olivine to millimeter-sized grains for carbonate formation (carbon sequestration) and ocean de-acidification.  The actual production profile of the wind turbines ceases to matter.

How much of the cost of an industrial wind turbine is in the generator and electronics?  Replacing them with a hydraulic pump to power machinery in real time, and making them directly useful for environmental remediation instead of only indirectly by displacing FF generation (which nuclear does much better), could be the best of both worlds.


Not very funny?

Intermittent e-energy sources could be used for regular loads with variable (hydro or NGPPs) sources as back-up and for peak demands.

To meet frequent higher peak demands, many hydro plants could be over equipped with extrta (50% or so depending on the RE production) turbines-generators.


What makes you think I was joking?  Are you that obtuse?


The idea is to electrify as many processus as possible and stop burning coal, oil, NG and bio-fuels and close down current inadaquate Nuke plants.

Of course more clean REs (with storage) will have to be installed. The H2 avenue may become one of the way to do it.

All technologies required to electrify ground vehicles (including trains) exist. It may become possible to electrify small and large planes by 2040/2050 or so.

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