Iron pyrite (Figure 1), the most abundant sulfur mineral, potentially can serve as a catalyst, say researchers at Cambridge University, Cambridge, U.K. First-principles electronic structure calculation coupled with ultra-high-vacuum single-crystal experiments indicate the material can catalyze the reduction of nitrogen oxides, they report.
Work underway aims to identify and quantify reaction products and to provide a fairly complete picture of the range of possibilities for using the pyrite as a catalyst, notes Stephen Jenkins of the school's department of chemistry, who is heading the research.
"Even if the new process were to be less efficient than one catalyzed by platinum, say, the economics of using an abundant mineral like pyrite could be the deciding factor," he explains. "…We feel that the most interesting possibilities for pyrite-based catalysts lie in applications where huge quantities of catalysts are required (e.g., production of commodity chemicals or vehicle emission controls)."
Such catalysts may offer an additional benefit, Jenkins says. "…Many traditional catalysts are poisoned by sulfur, which can block surface sites over time. Using a catalyst that is itself a sulfur compound may give an advantage, since the surface is, in effect, already saturated with sulfur… This can be particularly important when dealing with hydrocarbon feedstocks from low-quality sources or derived from biomass."
The researchers hope to explore the catalytic potential of a wide range of sulfidic and carbidic materials.