Controllably Engineering Mesoporous Surface and Dimensionality of SnO₂ toward High-Performance CO₂ Electroreduction

Currently, the precise control of the architecture and surface of functional materials for high-performance still remains a great challenge. Here, a feasible approach is presented to synchronously manipulate mesoporous surface and dimensionality of SnO₂ catalysts into hierarchically mesoporous nanosheets and nanospheres within one simple reaction system. By adjustment of the hydrophobic chain length of different fluorinated surfactants, 0D SnO₂ nanospheres with average size of 165 nm, and 2D SnO₂ ulthrathin nanosheets with thickness of 22.5 nm with the distinct dimensionalities are separately obtained (one stone, two birds), both of which are well decorated with ordered mesopore arrays on their surfaces (pore size of 16 nm). The following calcination gave rise to the formation of hierarchically mesopores (5 and 16 nm, respectively) with high crystallization and improved surface area (96.8 m² g⁻¹). The resultant mesoporous SnO₂ nanosheets as catalyst for CO₂ electroreduction reaction (CO₂ RR) exhibit excellent selectivity, with a high Faraday efficiency (FE) of HCOOH reaching up to 90.0% at −1.3 V and C₁ FE of 97.4% at −1.2 V versus reversible hydrogen electrode, as well as long-term stability, which is among the best performance compared to reported SnO₂ materials, thanks to the collective contributions of the unique architecture and mesoporous structure.