LAUSR

The CO2 capture and its photocatalytic conversion (CCPC) to solar fuels is one promising route to fighting global warming. The CCPC process implies the use of CO2, solar light, and materials to produce solar fuels of low carbon content. The materials must fulfill with the double function of capture and photocatalytic convert of the CO2 into solar fuels. For this purpose, copper oxide (CuO) is an excellent candidate to act as both: adsorbent and photocatalyst. Scaling-up the CCPC process requires the immobilization of CuO on commercially available substrates such as glass fibers, which offers a homogeneous surface exposure, efficient absorption of solar energy, and an easy application in reactors. In this work, the fabrication of CuO coatings on glass fibers by a simple microwave-hydrothermal method to produce solar fuels (CH3OH and HCOH) in CCPC process is proposed. Three glass fibers with different chemical compositions and slit (open area) were selected as supports. The best efficiency for CO2 capture (3080 mgCO2 g−1) was obtained with the CuO coating deposited in a substrate rich in Na2O and CaO. Once the CO2 was adsorbed, the coatings were exposed to visible LED light to carry out its conversion to solar fuels (CH3OH and HCOH). According to the results, both high CuO content and high slits in the fibers promoted an increase in the CO2 conversion to HCOH (2.7 nmol cm−2 h−1) and CH3OH (37.6 nmol h−1 cm−2). The presence of Na2O in the substrates played an essential role as a hole scavenger in the photocatalytic CO2 reduction, preventing the re-oxidation of the products. The use of glass fibers as support of CuO promoted efficiencies up to 11 times higher than other materials used in CCPC process.