Work

Atmospheric CO2 splitting using a visible light-driven Z-scheme photocatalyst in a gas-phase flow reactor

Year: 2026

Type: preprint

Abstract: Direct air capture (DAC) coupled to photocatalytic CO 2 splitting offers a route to simultaneously mitigate atmospheric CO 2 accumulation and produce sustainable fuels. However, integrations of DAC with photocatalytic CO 2 conversion have thus far relied on ultraviolet-light-absorbing TiO 2 and organic substrate oxidation, limiting solar energy utilisation and precluding a truly artificial photosynthetic reaction. Here, we introduce an integrated direct air carbon capture and utilisation (DACCU) system that couples under continuous flow nighttime atmospheric CO 2 capture with daytime gas-phase photocatalytic CO 2 splitting to CO and O 2 using a solid silica−amine adsorbent and a γ-Al 2 O 3 -supported visible-light-absorbing Z-scheme photocatalyst system, respectively. Gas-phase operation benefits CO 2 delivery and suppresses H2 evolution, achieving ~88% CO selectivity and ~100 h stability. Isotopic labelling confirmed that CO and O 2 originates from CO 2 and water, respectively. The DACCU prototype was operated outdoors over two consecutive day–night cycles, enabling continuous DAC at night with solar-thermal desorption and solar-driven conversion in the day. This work represents the first demonstration of producing solar fuels from only atmospheric CO 2 and moisture at low temperature and pressure and therefore provides a critical advance for the practical deployment of photocatalytic CO 2 splitting technologies.

Source: ChemRxiv

DOI: 10.26434/chemrxiv.15008316/v1