Photo‐Electrochemical Conversion of CO ₂ Under Concentrated Sunlight Enables Combination of High Reaction Rate and Efficiency

Photo-electrochemical production of solar fuels from carbon dioxide, water, and sunlight is an appealing approach. Nevertheless, it remains challenging to scale despite encouraging demonstrations at low power input. Higher current densities require notable voltage input as ohmic losses activation overpotentials become more significant, resulting in lower solar-to-CO conversion efficiencies. A concentrated photovoltaic cell integrated into a custom-made heat managed photo-electrochemical device. The transferred the module zero-gap electrolyzer by stream anodic reactant produce synergetic effects on both sides. With concentrations up 450 suns (i.e., kW m−2) applied for first time reduction CO2, partial CO 4 achieved. At optimal conditions, efficiency reaches 17% while maintaining density 150 mA cm−2 selectivity above 90%, representing overall 19% solar-to-fuel efficiency. This study represents demonstration CO2 under highly light, paving way resource efficient fuel high