Illuminated rhodium breaks up carbon dioxide

Carbon dioxide has been converted to methane by illuminating rhodium nanoparticles with ultraviolet light. Using light to break down carbon dioxide (CO₂) in the atmosphere is a long-sought-after mechanism. Not only could it start reducing the environmental impact of human CO₂ emissions, the methane could be used as a renewable source of energy. Scientists at Duke University in the US have broken apart CO₂ using tiny, cubic rhodium particles and ultraviolet light. Rhodium is a rare, inert metal that is already used in small amounts to speed up chemical processes in industry. To catalyse such reactions, an extra energy input is required and heat is typically used. Using rhodium nanoparticles, Jie Liu and team compared the breakdown of CO₂ using heat and ultraviolet light. They found that not only is the reaction more efficient when using light, it almost exclusively produced methane rather than a mix with carbon monoxide. The group suggests that the light generates energetic electrons that activate the necessary intermediates for methane production, while barely affecting chemical bonds involved in carbon-monoxide production. Next, the team hopes that tweaking the size of the nanoparticles will mean that sunlight can power the reaction. The work is presented in Nature Communications.

UK invests £229m in new research institutes

The UK government has announced it will provide £129m for a new materials centre located at the University of Manchester. Once open in 2019, the £150m Sir Henry Royce Institute for Advanced Materials will perform research in a range of areas from 2D materials to advanced metals processing, nuclear materials and energy storage. The institute was first mooted in 2014 by former UK Chancellor George Osborne and in late 2015 it was revealed that Julia King, a former chief executive of the Institute of Physics, which publishes Physics World, will chair the new centre. Meanwhile, the UK government has also announced that it will invest £103m in the Rosalind Franklin Institute – a new hub for life and physical sciences. Based at Harwell in Oxfordshire, it will be led by optical physicist Ian Walmsley from the University of Oxford. The institute, together with seven other partner sites, will aim to develop new technologies to tackle major challenges in health and life sciences, such as developing new treatments for chronic diseases.

Rotation sensor could be made from interfering ions

A proposal for a compact yet highly sensitive device that detects rotation using ions has been unveiled by physicists in the US. The sensor, which has yet to be built in the lab, is based on a Sagnac interferometer. This involves splitting a wave into two signals and sending the signals in opposite directions around a ring before recombining the signals at a detector. A change in how the interferometer is rotating will affect how the two signals interfere at the detector. This Sagnac effect is already used in optical gyroscopes in which light is sent in opposite directions around a coil of optical fibre. Now, Wes Campbell and Paul Hamilton of the University of California, Los Angeles, have proposed a scheme that uses ions to make an accelerometer that should combine high sensitivity with very small size. The wave–particle duality of quantum mechanics means that the ions behave like waves as they travel through the interferometer – which is based on an ion trap. Crucial to the success of the design, according to Campbell, is that the matter waves complete many circuits of the interferometer – much like light in a fibre coil. This would allow a practical device to be made much smaller than existing matter-wave gyroscopes, which are based on beams of atoms. If built, their device is expected to be as sensitive as existing commercial optical gyroscopes. However, writing in Journal of Physics B: Atomic, Molecular and Optical Physics, Campbell and Hamilton say that the performance could be improved. Although the device is only sensitive to changes in rotation, Campbell says it could be possible to use an ion trap to create a linear accelerometer. This could be paired with a rotation sensor to create GPS-free navigation systems that could be used on spacecraft and other vehicles used in locations where GPS is not available.

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