Ambient Sunlight Driven Photothermal Green Syngas Production at 100 m3 Scale by the Dynamic Structural Reconstruction of Iron Oxides with 38.7% Efficiency

Abstract

Ambient sunlight-driven photothermal green syngas production via reverse water-gas shift (RWGS) reaction is important for carbon neutrality, which lacks efficient and inexpensive catalysts at low temperatures. This studydemonstrates that the scalable Fe₃O₄ supported with K atoms modified Ag nanoparticles (AgK/Fe₃O₄) exhibits a RWGS CO production rate of 1089 mmol g⁻¹ h⁻¹ at 300 °C and 100% CO selectivity through dynamic structural reconstruction, surpassing all reported platinum-based catalysts. In situ characterization and theoretical simulation indicate that the AgK nanoparticles activate H₂ to reduce Fe₃O₄ as metallic Fe. Subsequently, the metallic Fe spontaneously reacts with CO₂ to form CO and Fe₃O₄, thereby facilitating low-temperature RWGS. Owing to its superior low-temperature performance, AgK/Fe₃O₄ equipped with a homemade photothermal device achieves one sun-driven photothermal RWGS with a CO production rate of 1925 mmol g⁻¹ h⁻¹ and a 38.7% solar to enthalpy energy conversion efficiency. Furthermore, the enlarged outdoor demonstration yields 100.6 m³day⁻¹ of green syngas with an H₂/CO ratio of 3. This work paves the way for designing efficient platinum-free CO₂ hydrogenation catalysts and introduces a new approach for sunlight-driven scalable green syngas production.