When it comes to renewable energy, more correct to speak of the sun – it was from him, ultimately, depend on other sources such as wind and biomass. However, solar panels convert light energy into heat and electricity – under the current development of technology, none of these types of energy can not be stored with a density sufficient for transport. This limitation is entirely responsible for the increased attention being paid to the development of biofuels and the use of electricity to produce hydrogen. However, each step in the chain of energy adds potential problems and reduces the efficiency of conversion.
Given these problems described in the latest issue of Science system looks very interesting. The authors demonstrated a device that can use solar energy to split water directly and the release of its oxygen and hydrogen. The same operation system may hold with carbon dioxide, converting it into carbon monoxide and oxygen. What’s remarkable – the system does not need an exotic catalyst. It operates on the basis of cerium – element is as common as copper.
Structure of the device is extremely simple. Most of it is a focusing lens, directing sunlight through a quartz window into the reaction chamber. It is designed to maximize the reflection – it is necessary to capture the largest possible number of photons. “Approximate absorption capacity of the chamber is 0.94, which is approaching the limit of an absolutely black body” – the authors say.
After photon absorption, they are converted into heat – the temperature in the chamber rises to 140 degrees Celsius per minute until it is stabilized in the range of 1400-1600 degrees. This is sufficient to initiate the reaction in the catalyst – the cylinder, which consists of porous cerium dioxide. At this temperature, cerium dioxide, releasing one of two oxygen atoms. Passing a stream of inert gas through the porous cylinder, the researchers noted the presence of a steady stream of oxygen.
After the oxygen flow dries up, the device is cooled to 900 degrees Celsius and pumped into the chamber reagent (water). As a result of evaporation of water the catalyst is reduced to cerium dioxide, in parallel there is a quick and easy release of hydrogen.
Of course, the system has its drawbacks. Requires a steady stream of inert gas, and water and carbon dioxide fed into the chamber must be clean – the effectiveness of the catalyst will be reduced significantly if it “will acquire” impurities. However, the optimism inspired by the fact that scientists have developed a system with an eye to ease of mass production and integration of production chains. So that researchers can work in the future to give us an effective, and most importantly – applicable to real-world way to produce hydrogen.
