A New Phase Indium Tin Oxide (ITO) Activated Selective CO₂ Reduction into Formate for Underwater Antifouling Glass

Designing unique electrocatalysts that utilizes carbon dioxide reduction reaction (CO₂RR) for real applications is highly appreciated, yet still suffers from low selectivity, stability, and compatibility. Herein, we first report a new two-dimensional metastable-phase transparent conducting oxide: 1T phase indium tin oxide (m-ITOs) with the space group of P-3m1 (164), which is totally different from that of the stable cubic phase ITO (Ia-3 (206)). The internal indium tin catalytic pairs in m-ITOs trigger the strong electronic coupling, move up the p-band center, and stabilize the adsorption of HCOO* for increased formate production. In a liquid-phase flow cell, m-ITOs exhibit a high CO₂RR electrocatalytic performance with the formate selectivity up to 93 ± 1.9% (83 ± 3.1% for c-SnInO_x and 74 ± 0.6% for In₂O₃/SnO₂) and remains 97% (58% for c-SnInO_x and 60% for In₂O₃/SnO₂) of catalytic activity after a 120,000 s stability test. Owing to the efficient formate formation with directly using the absorbed CO₂ in water and high transparent property, m-ITOs exhibit excellent antifouling behavior of inhibiting Chlorella growth without reducing the transparency of itself, encouraging a promising application of observation windows in water.