## New high-activity, low-cost nickel-based catalyst for fuel cells exhibits performance similar to Pt; hydroxide exchange membrane fuel cells

##### 15 January 2016

Researchers at the University of Delaware, with a colleague at the Beijing University of Chemical Technology, have developed a composite catalyst—nickel nanoparticles supported on nitrogen-doped carbon nanotubes—that exhibits hydrogen oxidation activity in alkaline electrolyte similar to platinum-group metals. An open access paper on their work is published in the journal Nature Communications.

Although nitrogen-doped carbon nanotubes are a very poor hydrogen oxidation catalyst, as a support, they increase the catalytic performance of nickel nanoparticles by a factor of 33 (mass activity) or 21 (exchange current density) relative to unsupported nickel nanoparticles, the researchers reported. Owing to its high activity and low cost, the catalyst shows significant potential for use in low-cost, high-performance fuel cells, the team suggested.

Polymer electrolyte membrane (PEM) fuel cells are based on two half-cell reactions: hydrogen oxidation reaction (HOR) at the anode and oxygen reduction reaction (ORR) at the cathode. Pt is the most active catalyst for both HOR and ORR; the high price of the metal (~$50 g−1) has hindered fuel cell commercialization. This, in turn, has compelled engineers to (1) work to reduce the platinum loading in the membrane assemblies and (2) find alternate, lower-cost catalysts that offer comparable performance to platinum. Although the various efforts have managed to reduce the total content of platinum-group metals (PGMs) in the state-of-the-art proton exchange membrane fuel cell (PEMFC) stacks, more than 0.137 g Pt kW−1 is still needed, the University of Delaware team said. One promising approach to reduce the cost of fuel cells is to switch the operating environment from an acidic to a basic one (that is, a hydroxide exchange membrane fuel cell, HEMFC), thus opening up the possibility of using PGM-free catalysts and other cheaper components. For the cathode of the HEMFC, some PGM-free and metal-free ORR catalysts have been developed that show comparable activity to Pt in alkaline media. However, for the anode side, only a few PGMs (for example, Pt, Ir and Pd) show adequate activity. The HOR catalyzed by Pt is very fast in acidic conditions so that a very low loading of the Pt catalyst could be used relative to the cathode side in PEMFCs. However, the HOR activities of PGMs are ~100 times slower in alkaline solutions. As a result, a much higher loading of the HOR catalyst is required (0.4 mg Pt cm−2 in a HEMFC compared with 0.03 mg Pt cm−2 in a PEMFC) to achieve similar performance. Thus, it is highly desirable to develop PGM-free anode catalysts for the HOR in alkaline electrolyte. Unlike its reverse reaction (hydrogen evolution reaction, HER), only a few PGM-free HOR catalysts have been reported. One possibility is to use Raney Ni as the HOR catalyst in liquid alkaline fuel cells. However, it is functional only under very high alkalinity (6 M KOH) while the activity remains low. It is not catalytically active for a HEMFC, which can be mimicked as 0.1–1 M KOH. Efforts have been made to improve the HOR activity of the Ni-based catalyst in the last decade. Ni alloys, such as NiMo and NiTi, have been shown to enhance the HOR activity. Our recent work has also shown that electrochemically deposited NiCoMo on an Au substrate has a high HOR activity. Zhuang and co-workers decorated Ni particles with CrOx to weaken the Ni–O bond and stabilize the Ni catalysts. A HEMFC incorporating this PGM-free catalyst has been fabricated, and it exhibits a peak power density of 50 mW cm−2. Although the power density is still low (compared with the peak power density of more than 1,000 mW cm−2 for PEMFCs), it demonstrates the possibility to fabricate low-cost PGM-free fuel cells. However, their activities are still incomparable with PGM-based catalysts. —Zhuang et al. In the Nature Communications study, the team synthesized Ni nanoparticles supported on N-doped carbon nanotubes (Ni/N-CNT) using a wet chemical method. The nanotubes are not only the support for the Ni nanoparticles, but also a promoter for the catalytic activity. Using density functional theory (DFT) calculations to understand the interaction between the Ni nanoparticle and the N-CNT support, the team found that, when nitrogen dopants are present at the edge of the nanoparticle, the Ni nanoparticle is stabilized on the support and locally activated for the HOR because of modulation of the Ni d-orbitals. Owing to its high activity and low cost, Ni/N-CNT has great potential to be used as the anode in HEMFCs, thereby finally bringing to fruition a high-performance and low-cost PGM-free HEMFC. —Zhuang et al. This new hydroxide exchange membrane fuel cell can offer high performance at an unprecedented low cost. Our real hope is that we can put hydroxide exchange membrane fuel cells into cars and make them truly affordable—maybe$23,000 for a Toyota Mirai. Once the cars themselves are more affordable, that will drive development of the infrastructure to support the hydrogen economy.

—Yushan Yan, corresponding author

The experimental work was supported by the ARPA-E program of the US Department of Energy under Award Number DE-AR0000009.

The computational work was financially supported by the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001004.

Stephen Giles was supported by a fellowship from the University of Delaware Energy Institute.

The research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Resources

• Zhongbin Zhuang, Stephen A. Giles, Jie Zheng, Glen R. Jenness, Stavros Caratzoulas, Dionisios G. Vlachos & Yushan Yan (2016) “Nickel supported on nitrogen-doped carbon nanotubes as hydrogen oxidation reaction catalyst in alkaline electrolyte” Nature Communications 7, Article number: 10141 doi: 10.1038/ncomms10141

Those seeking to rule out hydrogen and fuel cells on sweeping a priori grounds seem to be having the legs kicked out from under their position one by one.

This progress comes on top of umpteen advances in solar to hydrogen and so on.

It is a done deal?

Absolutely not.

But neither are the far better and cheaper batteries somewhat glibly assumed by batteries only and everywhere advocates.

Seeing how things develop is often a more effective strategy than seeking to rule out whole fields of technology on the basis of some back of the envelope and often erroneous arithmetic.

I don't disagree, Davemart. No technology or solution should be dismissed a priori.

But if you look at the relative maturity and market pricing of BEV vs FCV, one is winning handily; 500,000 vehicles vs less than 500. 20,000 public charging stations vs 8 in the US.

The non-platinum catalyst announced above is exciting. But hydrogen as a transportation fuel is still "four miracles" from being commercially competitive.

GM will start producing 30,000 Chevy Bolts next year. Toyota will produce 3,000 Mirai.That's if the hydrogen stations currently in planning and construction get built; Toyota just this week told some dealers to *stop selling the Mirai* until more stations are deployed.

These are simply the current market realities.

FCEVs have major catching up to do but improved lower cost PEMs is part of it.

More lower cost H2 stations will be around soon.

FCEVs, with their inherent proven extended range and very quick charges/refills + free cabin heat source + ideal as emergency power source for long outages etc will outdo BEVs in many applications.

They have reduced the amount of Pt closer to the amount used in catalytic converters, a good trade for less smog and imported oil.

"According to the DoE, the amount of platinum in PEM fuel cells has decreased by around 80% during the past decade.."

http://www.fuelcelltoday.com/analysis/analyst-views/2013/13-11-06-the-cost-of-platinum-in-fuel-cell-electric-vehicles#sthash.N3lY9Yrn.dpuf

Even if the cost of the fuel cell is dealt with, you have only got one of the required FOUR miracles.  Hydrogen production, storage and distribution aren't helped by developments in FCs.

Batteries are too useful for development to rely on the vehicular market.  Teslas run on cells designed for the laptop market.  The EV can go essentially anywhere there's an outlet, today; fast-charging stations have already sprouted like weeds.  Hydrogen is far behind in cost per mile.  I see no way for it to remain in play, absent subsidies and outright mandates.

I keep telling you guys that there is more to life than cost per mile, if the costs are already reasonably low. The reasons batteries have problems for all use cases should be obvious but some zealots simply fail to see it. I used to be one of those zealots but reality intruded years ago.

An EV fast charge is NOT currently fast enough for many usage cases. There are people out there who will NOT accept having to wait around (or find something to do for all of 30 minutes or more) when they want to "Get Somewhere" expeditiously. It really is that simple.

The only way EVs fully take over (99.9%) is if there is a true breakthrough and one can go at least 350 miles and have the ability to recharge / refuel fully in 10 minutes or less. Now, if range gets closer to 500 miles, the recharge time requirement can be relaxed accordingly.

One other thing, H2 production is definitely helped by developments in FCs given the symbiotic relationship between FCs and electrolyzers. They are essentially the same device, just operating in reverse and use similar components. Any reduction in FC price, catalyst requirements etc. will apply to electrolyzers, the only question being the magnitude of the reduction.

If the roads themselves are wired, EVs can charge in motion and stopping for energy becomes a thing of the past.

But just pondering... how many humans have a range of 500 miles (at highway speeds, not aircraft) without stopping?

Sheldon, I'm curious. Under what real-life scenario do you see a FCV winning in the marketplace against a PHEV (or EREV if you prefer) with good all electric range (like the Chevy Volt or BMW i8)

When only your out-of-town trips are gas, the emissions would be miniscule. The inter-city infrastructure problem ceases to exist.

Given the realities of the cost differential, how does Hydrogen win?

oops, I meant BMW i3 (~80 mile electric range)

PEM fuel cell range extenders running on reformed renewable fuel would have a range of 400 miles and refill in 5 minutes. Bio CO2 and no NOX nor imported oil are also advantages.

We've got battery technologies coming that will charge in 5 minutes.  What's hydrogen good for then?

Crankshaft-free piston hydraulic pumping engines with digital controlled hydraulic motors and regeneration reservoirs have much higher efficiency and far lower costs than any possible fuel cell vehicle. The engine efficiency alone can be as much as 50% with little need for low temperature heat dissipation. ..HG..

Yes, whenever affordable very quick charge (5 minutes) higher energy density (800+ Wh/Kg) battery packs and improved chargers (200+ KW) charging facilities are available, BEVs will lead the ground vehicle markets.

However, at the current development rate, all that may not be available much before 2040 or so.

Meanwhile, FCEVs may be the (only) affordable solution for the next 25 years or so, specially for all weather operations.

Making enough H2, with clean electricity in the right places, should not be a major challenge. Current e-suppliers could be mandated to do it.

You also carry more than a 1000 pounds of batteries for 200 mile range. With a reformer, fuel cell and batteries it would be less than half that with twice the range.

I explain why straight 200 mile EVs cannot take over and the discussion switches to EREVs. If we are willing to live with continued burning of some carbon, then fine, EREVs will suffice. If our goals are :

1. Switch to 100% renewables and reduce carbon burden from sourcing energy
2. Provide the same flexibility as gasoline / diesel today

Straight EVs will not do it and there is no battery technology on the near or medium term horizon that will allow 5 minute recharging. I anxiously await any development in this area that proves my statement wrong. This does not even consider the issue of power requirements for fast charging at that rate and the cost and installation of such facilities.

FCEV and H2 technology today is hindered primarily by the chicken / egg scenario that prevents scale. No fundamental breakthroughs are required to provide similar functionality as gasoline/diesel today. Incremental improvements and refinements, yes such as increased lifespan, dispenser reliability, storage weight and volume etc., will help and I will bet that such would accrue with more experience and scale.

Another thing to consider. I have a 1.2 year old car, live in a medium sized city and do not rack up much in the way of urban miles. About 45% of the total mileage of about 13K is urban and the remaining is long distance. The longest such trip was a drive of about 600 miles, done in a single day with one fuel stop of 5 minutes and a combined meal/bathroom stop of 15 minutes in the same vicinity. The leg following the meal stop was over 300 miles and 5+ hours. This is not unusual behavior for "Road Warriors" out there and they are a decent proportion (5 - 10%) of population.

Even accounting for the better efficiency on long trips (45 - 50 mpg versus 35 - 40 mpg) in town, a significant proportion of my emissions will accrue due to the long trips for which the combustion engine in an EREV will be running. These stats are not unusual for anybody who lives in rural or smaller city US where many trips can be taken to nearby (200 - 400 mile) larger cities in the region, especially out West.

Date:  March 20, 2019.

Location:  Buttonwillow, California.

A Tesla Model 3 is the first vehicle to use the T-IMC "in-motion charging" system on I-5.  Moving to a new lane in the freeway median under automatic control and slowing to 45 MPH, the vehicle extended a robot arm to charging contacts built into the new guardrails.  5 minutes and 4 miles later, the electric thirst of its new FasCharge battery slaked, the car retracted its charging arm and rejoined the normal flow of traffic.  It would stop at a Supercharger outside Los Banos before completing its journey from Los Angeles to San Francisco.

Tesla says that in-motion charging will be available on I-5 from San Diego to Vancouver BC by October this year.  Negotiations for rights on I-10, I-15, I-40 and I-80 are in progress.

Chevy, Nissan and Ford have announced T-IMC compatible offerings in the 2020 model year.

Very clever, EP, that totally cracked me up, especially the sly reference to everyone's favorite rest stop, Los Baños.

You should see the first fake news article I ever wrote.  Mail me if you want me to dig up the link.

Sheldon, where are you getting your travel stats? I get mine from DOT and I can't see any that indicate so many long distance miles.

http://electric-car-insider.com/holiday-travel.php

FCV and H2 technology today is hindered primarily by the expense of the chickens and eggs.
It simply is not currently economic.

Mirai is $57,500. Toyota plans to sell 1,000 in 2017. Bolt is$37,500. Chevrolet plans to sell 30,000 in 2017.

A hydrogen fuel station costs about $4 million. It requires dedicated space. (Lower cost estimates bandied about are inaccurate - the$4m figure is from Toyota).

A 135kW Supercharger station with 8 stalls is estimated to cost about $250k. A supercharger station can occupy any convenient parking spaces - e.g. on the far edge of a parking lot. Parking function is shared while supercharger patrons eat, shop, etc. Road warriors who need quick turns can drive PHEVs. Its very unlikely the US will spend the$500billion to $1trillion* it would take to build a nationwide network of H2 stations to solve the quick turn needs of a very small fraction of drivers who need very long distance and very quick turn time. *DOE estimate. The numbers I reported are my own experience and driving. Don't need DOT to tell me what I did in the last two years. My situation is not unusual. I venture to guess and will put it out there for anyone to refute that at least 10% of drivers out there, especially if you do not live in a bigger metropolis make 5 or more trips per year that are at least 200 miles one way in length. It is hazardous to extrapolate averages in the manner that you do and fail to consider the distributions of the trips that lead to those averages. Examples like many short trips and fewer very long trips as I point out come to mind. As I said, if you are satisfied with continued burning of gasoline/diesel then we can keep going about our business. if we want to move forward to a cleaner, more emission free future, I can state with authority that BEV technology as you advocate cannot do the job in total. Even a Model S, with a nominal 300 mile range is not adequate to do trips (without the pain of at least a 10 - 15 minute stop) like North Florida to Central Florida at 75 - 80 mph for example that are commonly done without any kind of stop whatsoever or the stop is a 5 minute bathroom reliever break. Look, we will see as the roll out occurs. My prediction. Both technologies make inroads with BEVs having the headstart and ultimately with larger market share and FCEVs using nat gas derived H2 initially, catching up later to service the more difficult situation for which BEVs will continue to be weak. > Even a Model S, with a nominal 300 mile range is not adequate to do trips I believe your experience is unusual, especially when price is considered, as most people will. I routinely drive my Model S from Seattle to San Diego, or to the Bay Area, etc. It is very little inconvenience to stop for 30-45 minutes after 3 hours of driving and have a meal, or take a stretch and grab a cup of coffee. No inconvenience at all when my *fuel at that stop is free* saving me at least$60 each time.

Even at 5 trips a year (as you suggest) people would only be adding maybe 10 hours of total rest/charging breaks in a year - in exchange for a yearlong fuel savings of $1,500 -$2,000 per year. I'm guessing that most people, once they figure it out, would gladly make that trade.

Getting off fossil fuels is definitely the goal. But hydrogen derived from methane doesn't accomplish that (even if it's only 66% derived from methane) and paying $500 billion to$1 trillion for an H2 infrastructure is very unlikely to happen - especially considering that the only "problem" it solves is those very long trips which *require* very fast turn times.

Give that enough thought and the conclusion is inescapable.

There's 'need' and there's 'desire'.

We had a federal polie resign recently after the cafuffle over their 'need to taxpayer funded charter a limo helicopter for a function that would have been a one hour road trip by com(monwealth)car or as our current chief prefers - bus and rail.

The cost for the return charter annoyed the accountant in all of us.

On the other hand I have to suffer for 4-5 hours dirty highway restrooms trucks and the heat so must be much more deserving?

The point is that taking even a one hour break won't really do anyone too much harm in fact there will logically be a sharp decline in the accident statistics.

And why not take a little time out to practice some yoga?

EE Econ 101. Preserve capital. Buy a Compact Gasser and forget about it.

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