The Effect of SnO₂ Surface Properties on CO₂ Photoreduction to Higher Hydrocarbons

Abstract

Several photocatalysts have been developed for applications in reduction reactions, including tin oxide-based semiconductors. Although its band structure is unfavorable for CO 2 reduction reactions, strategies to modify its surface properties directly impacted its activity and selectivity during these reactions. Here, we analyze the influence of heat treatment and decoration of SnO 2 with gold nanoparticles on the gas phase CO 2 photoreduction process. In both cases, a deleterious effect was observed during reactions under UV radiation (with a drop of 59.81 % and 51.45 % in CH 4 production for SnO 2 _150 °C and SnO 2 /Au_cop, respectively, compared to SnO 2 _cop), which is directly related to the availability of surface hydroxyl groups that play a crucial role in CO 2 adsorption. Under visible radiation, the gold plasmonic resonance took place in the production of methane (0.33 μmol g À 1 for SnO 2 /Au_cop and 0.29 μmol g À 1 for SnO 2 /Au_150 °C), with small amounts of carbon monoxide (0.06 μmol g À 1 for SnO 2 /Au_cop and 0.03 μmol g À 1 for SnO 2 /Au_150 °C). These results demonstrate that, though the SnO 2 band structure does not indicate a good semiconductor for CO 2 reduction, its surface characteristics are responsible for its catalytic activity.

CO2 Photoreduction Product Selectivity with TiO2−Cu Nanocatalysts under Different Reaction Media

“…[2] It is a sustainable, low-cost route that does not require thermal energy to reduce CO 2 into products of interest (methane, methanol, ethanol, acetic acid, isopropanol, and higher hydrocarbons), in addition to hydrogen (H 2 ) as a green fuel. [3][4][5] Many efforts have been made to produce efficient and selective catalysts for photocatalytic conversion of CO 2 . Currently, several metal oxides have demonstrated high potential for photocatalytic activity (TiO 2 , ZnO, WO 3 , SnO 2 , SiO 2 , Nb 2 O 3 , and others), among which titanium dioxide (TiO 2 ) is the most widely used photocatalyst.…”

“…In this sense, photocatalysis presents itself as a promising proposal to solve the energy crisis and environmental concerns [2] . It is a sustainable, low‐cost route that does not require thermal energy to reduce CO 2 into products of interest (methane, methanol, ethanol, acetic acid, isopropanol, and higher hydrocarbons), in addition to hydrogen (H 2 ) as a green fuel [3–5] …”