Catalysts based on volcanic-origin materials for CO2 reduction

Volcanic eruptions release large annual quantities of volcanic material and gases to the Earth's crust surface. This volcanic-origin material includes lava flows, pyroclastic materials, ashes, sands, solidified lava, and generally any material expelled by a volcano. Various compositional analyses of these volcanic materials show that they also contain traces of heavy metals such as Ni, Zn, Zr, As, Cd, Cu, Co, Cr, and Pb, as well as rare earth elements like Hf, U, Ce, Eu, La, and Sm, among others. The quantities of these heavy metals or rare earth elements vary depending on the geographic location of the volcano. Additionally, the composition of the different volcanic materials from the same eruption, such as ashes, sand, or rock, does not show significant differences in their major components, although there may be slight variations in the percentages of minor components. However, the direct application of volcanic-origin material as heterogeneous photocatalysts for the decomposition of H2O into H2 and/or O2, or the reduction of CO2 or N2 into value-added compounds, has not been studied. Some of the value-added compounds that can be obtained from CO2 through photocatalytic reduction include methane, methanol, carbon monoxide, formic acid, ethane, ethylene, among others. Compounds that can be obtained from N2 through this process include ammonia, among others. The present invention describes the photocatalytic activity of volcanic-origin materials for water decomposition, CO2 reduction, and N2 reduction.