Highly Dispersed Indium Oxide Nanoparticles Supported on Carbon Nanorods Enabling Efficient Electrochemical CO₂...

Indium-based materials can selectively reduce CO₂ to formate, but their activities still fall short of expectations to be considered for practical applications. Structural engineering at the nanoscale offers a promising solution. However, it is challenging to directly prepare nanostructures of metallic indium because of its low melting point and high oxophilicity. Herein, a strategy to prepare highly dispersed indium oxide nanoparticles as the precatalyst supported on conductive carbon nanorods from annealing the MIL-68 (In) precursor is proposed. When assessed in an H-cell, the product enables CO₂ reduction to formate with great faradaic efficiency of around 90% over a wide potential window in 0.5 m KHCO₃. When applied in a gas-diffusion-electrode-based flow cell, the catalyst delivers large current density of up to 300 mA cm^-2 in 1 m KOH, great formate faradaic efficiency and decent stability. These results indicate the commercial viability of the catalyst even though the carbonate buildup at the gas diffusion electrode remains an issue of future research.