Technion-Israel Institute of Technology

A new solar-powered catalyst made of graphene and titanium dioxide nanoparticles can pluck pollutants out of the air, much more efficiently than others. The catalyst could be coated onto building or street surfaces to improve air quality in cities.

In order for microscopic "nanobots" to get to their destinations, they'll need some form of propulsion. A team of Israeli and German scientists has responded by creating what they claim is the world's smallest propeller.