Researchers studied how a solid's pores change the way it reacts chemically with other substances. As a result, steel production could become more environmentally friendly.
The use of hydrogen is potentially more environmentally friendly compared to the standard procedure using carbon as the reactant. However, for this change to be implemented on an industrial scale, a number of hurdles must be overcome. One of the problems is that one of the reactions required to make steel from hydrogen is eerily slow. Xuyang Zhou at the Max Planck Institute for Iron Studies in Germany and his colleagues have finally identified the root cause of this slowness and proposed a solution.
Iron oxide combines with another substance in a redox (electron trade) reaction to form an oxide byproduct such as carbon dioxide or water, depending on whether the steel and reactant are carbon or hydrogen. Zhou and colleagues were aware that the removal of oxygen atoms during this process leaves pores in the iron oxide ranging in size from nanometers to microns. They found that when the reactant is hydrogen, the water trapped in these pores can actually re-oxidize the iron (remove electrons), slow the overall reaction, and reverse the reduction (electron addition) process needed to produce steel.
The group proposes a countermeasure against this slowing effect. If the pores are connected enough to form channels, the water will have a chance to seep out of the material before it is re-oxidized. According to Zhou, the group should be able to produce the required pore morphology by regulating the temperature, pressure and other variables of the reaction.
According to Zhou, steel production currently contributes to 7-9% of the world's carbon dioxide emissions, so developing an alternative strategy is crucial to reducing greenhouse gas emissions and tackling climate change.
Source: physics.aps.org/articles/v16/s57
Günceleme: 20/04/2023 13:49