Monolithic NiO/WO3-Loaded Ceramic Fibers Enable Efficient CO2–H2O Conversion via Concentrated Photothermal Coupling

The intense photothermal coupling effect generated by concentrating light through Fresnel lenses can efficiently convert CO2 into high-value-added chemicals. However, the extreme high-temperature environment resulting from high photon flux simultaneously causes the agglomeration, sintering, and oxidative deactivation of catalyst powders, thereby limiting the large-scale application of concentrated photocatalytic technology. Here, we constructed a high-temperature-resistant monolithic catalyst by in situ growth of NiO/WO3 nanosheets on the surface of the silica–alumina fiber material (denoted as NiO/WO3/SAF) and applied it to concentrated solar-driven CO2–H2O catalytic conversion. During the concentrated photocatalytic process, NiO/WO3/SAF exhibited superior cycling stability compared to NiO/WO3 powder, which could be attributed to the excellent dispersion, stable anchoring, and thermal insulation effects provided by the SAF support for NiO/WO3. Furthermore, under the assistance of oxygen vacancy-induced photothermal effect in WO3, the high-energy and high-density charge carriers generated by concentrated light facilitated CO2 reduction at electron-rich NiO active sites. Consequently, under concentrated irradiation of 4.0 W·cm–2, NiO/WO3/SAF achieved a solar-to-chemical energy conversion efficiency of 0.37‰, with CO and CH4 yields of 461.7 μmol·g–1·h–1 and 125.7 μmol·g–1·h–1, respectively. This work provides a valuable strategy for the industrial development of solar-driven CO2 utilization.