There was a sensation in 2012 - researchers had described a graphene-based device converting ambient heat into electricity, in violation of the second law of thermodynamics. Yet only the technological aspects were discussed - the violation of the second law was not mentioned in the original paper and the comments (not even in Nature's comment):
"Graphene Battery Turns Ambient Heat Into Electric Current. Physicists have built a graphene battery that harvests energy from the thermal movement of ions in solution."
Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment, Zihan Xu et al: "Moreover, the thermal velocity of ions can be maintained by the external environment, which means it is unlimited. However, little study has been reported on converting the ionic thermal energy into electricity. Here we present a graphene device with asymmetric electrodes configuration to capture such ionic thermal energy and convert it into electricity. [...] To exclude the possibility of chemical reaction, we performed control experiments... [...] In conclusion, we could not find any evidences that support the opinion that the induced voltage came from chemical reaction. The mechanism for electricity generation by graphene in solution is a pure physical process..."
Nature: "Although materials scientist Yury Gogotsi of Drexel University in Philadelphia, Pennsylvania, doubts the latest claim, he points out that the mystery should at least be relatively easy to clear up. "The device described by Xu's group is very simple and numerous labs can easily repeat this experiment to check the validity of the results," he says. [...] Comments are closed."
Comments were really closed in 2012, and the promise that "numerous labs can easily repeat this experiment to check the validity of the results" was immediately forgotten.
In 2013 Zihan Xu and co published a similar paper, in a prestigious journal, and this time the violation of the second law WAS mentioned. That was fatal. Scientists do discuss violations in microscopic or nanosystems but a macroscopic violation of the second law of thermodynamics acts like the face of Medusa the Gorgon - on seeing it, scientists get petrified and never recover. So the second paper did not become a sensation - there were no comments at all:
Electricity generated from ambient heat across a silicon surface, Guoan Tai, Zihan Xu, and Jinsong Liu, Appl. Phys. Lett. 103, 163902 (2013): "We report generation of electricity from the limitless thermal motion of ions across a two-dimensional (2D) silicon (Si) surface at room temperature. [...] ...limitless ambient heat, which is universally present in the form of kinetic energy from molecular, particle, and ion sources, has not yet been reported to generate electricity. [...] This study provides insights into the development of self-charging technologies to harvest energy from ambient heat, and the power output is comparable to several environmental energy harvesting techniques such as ZnO nanogenerator, liquid and gas flow-induced electricity generation across carbon nanotube thin films and graphene, although this remains a challenge to the second law of thermodynamics..."