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2-D Materials


The power of poop

by Sam Lemonick
February 1, 2020 | A version of this story appeared in Volume 98, Issue 5


Crappy catalyst

Stock photo of an inquisitive-looking chicken.
Credit: David Benton/Shutterstock
Poo-D material: Chicken poop enhances graphene's catalytic powers.

Pure graphene, a 2-D carbon allotrope, is a decent catalyst on its own, but scientists have found that adding small amounts of heteroatoms like sulfur, potassium, or halogens—a process called doping—can improve the material’s performance. That observation has unleashed a wave of papers measuring the effect of doping graphene with one or several elements. Martin Pumera of the University of Chemistry and Technology, Prague, thinks scientists are flushing resources down the drain, publishing paper after paper showing that different dopants improve graphene catalysis rather than figuring out why dopants have the effect they have on graphene.

To make the point, Pumera—who also has appointments at Brno University of Technology and China Medical University—and colleagues doped graphene with literal crap from a collaborator’s chickens and showed that it too improved graphene’s electrocatalytic performance (ACS Nano 2020, DOI: 10.1021/acsnano.9b00184). They prepared graphene oxide, a graphene precursor, by two methods and then blended it with bird droppings before making graphene via thermal exfoliation (technically, the researchers made reduced graphene oxide, which is similar to graphene but easier and cheaper to make). They then measured how well it worked in standard oxygen-reduction and hydrogen-evolution reactions.

Pumera says his goal wasn’t to convince people that dropping-doped graphene is a viable catalytic material, although, he says, considering their results and chicken poop’s very low cost, it may have potential. Nor was he going for a cheap joke. The point, he says, is to draw attention to the current trend of doped-graphene research, which he doesn’t think increases our understanding of how doping improves graphene catalysis. The study is making a splash—within 2 days of publication, the article was the journal’s most-read paper of 2020.


The poo-llusionist

Stock photo of a rubber hand.
Credit: Yang H. Ku/C&EN
Look, no hands: Researchers explore if fake hands and fake poop can help treat obsessive-compulsive disorder.

Some people with obsessive-compulsive disorder (OCD) may have found it hard to read the first half of this page. Uncontrollable fear of dirty things, like chicken poop, is a common symptom, and that fear can be debilitating.

One treatment for OCD is exposure therapy, in which patients might inoculate themselves by intentionally touching something repulsive. It can be effective, but some people with OCD can’t bring themselves to start or stick with the therapy.

Baland Jalal, previously affiliated with the University of Cambridge and Harvard University, has an idea to make exposure therapy a little less gross. He and his colleagues are exploring whether a form of exposure therapy using a fake hand and fake poop can help people with OCD by tricking their brains into thinking they’re touching the real thing (Front. Hum. Neurosci. 2020, DOI: 10.3389/fnhum.2019.00414).

The research is based on the rubber-hand illusion. A person sits with their hand resting on a table but hidden from their view. What the person does see is a realistic rubber hand, and when an experimenter strokes the fake and real hands with brushes at the same pace, the person’s brain, feeling a brush on their real hand and seeing a brush on the fake hand, feels like the fake hand is their real hand.

These researchers’ twist was to next touch the fake hand with fake feces (made from chocolate, peanut butter, and novelty poop-scented spray) while touching the real hand with a wet tissue. The group had previously shown that the procedure grossed out healthy volunteers, and in this study, they showed that people with OCD also reacted strongly, even though they knew it was fake.

Jalal tells Newscripts that the small study is a step toward a new therapy, but the results suggest it could be a good alternative to traditional exposure therapy or more expensive variants, like virtual reality.

One more thing: Jalal graduated from Cambridge with his PhD last month. Congratulations, Dr. Jalal!

Sam Lemonick wrote this week’s column. Please send comments and suggestions to


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