Concentrated Full-Spectrum Solar-Driven CO₂ Reduction with H₂O to Solar Fuels by Au Nanoparticle-Decorated TiO₂

Abstract

Currently, the production of solar fuels by the photoreduction of CO 2 with H 2 O is limited by the slow reaction rate and low efficiency of solar energy conversion. Combining concentrated solar power and plasmonic nanomaterials is a promising strategy to enhance photothermal transformation and promote solarto-fuel conversion. Herein, a nanocatalyst comprising gold anchored on TiO 2 was fabricated using a regular deposition-precipitation method. The nanocatalyst showed improved performance in CO 2 reduction with H 2 O under concentrated full-spectrum irradiation owing to the coupling of photo-and thermal energies. Macroscopic experiments demonstrated a clear correlation between the light intensity and the syngas yield, and a CO 2 conversion rate of 6.35% was achieved after 3 h under simulated sunlight illumination of 1644 mW/cm 2 . Photoelectrochemical measurements and finite element method simulations indicated that Au/TiO 2 achieved better separation and transport of the photoexcited carriers than TiO 2 owing to localized surface plasmon resonance that heats the nanocatalysts under concentrated full-spectrum irradiation. In situ diffuse reflectance infrared Fourier transform spectroscopy analysis also suggested that the photothermal effect accelerates the formation of intermediates such as formate and acetate and therefore enhances the overall photocatalytic rate. These results highlight the excellent potential of combining concentrated solar power and plasmonic nanostructures to realize the synergistic utilization of photon energy and thermal energy. Such a combination not only promotes the solar-to-fuel conversion efficiency but also paves the way for future applications in large-scale scenarios.

Photothermal Coupling Effect Boosts the Conversion of CO2 to Solar Fuel Over Pt/ZnO Photocatalyst in a Concentrated Solar Reactor

“…Finally, the photocatalytic performance of 0.1Pt/ZnO in terms of energy conversion efficiency was compared with that of recently reported photocatalysts (Figure d and Table S5). Without external heating, the energy conversion efficiency of Pt/ZnO under concentrated light irradiation (4200 mW cm –2 ) was 0.264%, outperforming previously reported catalysts. ,− …”

“…Interestingly, compared with normal UV–vis irradiation, the photocurrent response under concentrated UV light irradiation was much higher. However, the yield was slightly lower than that under normal UV–vis irradiation (Figure c), this was mainly due to the increased intensity in the absorption of the visible light regions by the Pt nanoparticles, which converted partial light energy into heat energy, thus enhancing the yield . Similarly, the yield over 0.1Pt/ZnO under concentrated visible light was higher than that under concentrated UV light, this was because the non-radiative decay of the localized surface plasmon generated more hot electrons, which helped to accelerate the kinetic reaction of the photocatalytic reaction and make the catalyst exhibit good photocatalytic performance under concentrated visible light irradiation.…”

“…The optimal catalyst 0.1Pt/ZnO was purged with N 2 , exposed to a CO 2 /H 2 O vapor mixture for half an hour in the dark, and finally irradiated for 0.5, 1.0, 1.5, 2, 2.5, and 3 h. Multiple characteristic peaks were detected in the DRIFTS spectrum (Figure a) corresponding to adsorbed CO 2 and the corresponding reduced intermediates. Four different adsorption modes were observed for the CO 2 adsorbed on the 0.1Pt/ZnO surface, namely, b -CO 3 2– (1563, 1357, and 1334 cm –1 ), m-CO 3 2– (1531, 1485, and 1470 cm –1 ), • CO 2 – (1297 and 1513 cm –1 ), and HCO 3 – (1450 and 1431 cm –1 ). ,− Among them, HCO 3 – stemmed from CO 2 trapped by −OH. The presence of CO 2 – indicated that CO 2 adsorbed was injected with excessive electrons due to the strong electron-absorbing nature of Pt nanoparticles, resulting in the binding and activation of bonds .…”

In-situ monitoring of plasmon-induced nanoscale photocatalytic activity from Au-decorated TiO2 microflowers

“…The peaks at 458.47 and 464.24 eV are attributed to Ti 2p 3/2 and 2p 1/2 , respectively. Both peaks correspond to the Ti 4+ oxidation state [64]. The high-resolution XPS Ti 2p spectra of TA-4 is shown in figure 8(c).…”

Emerging Single-Atom Catalysts and Nanomaterials for Photoelectrochemical Reduction of Carbon Dioxide to Value-Added Products: A Review of the Current State-of-the-Art and Future Perspectives

“…One alternative gaining a lot of focus worldwide is converting CO 2 into value-added products. There are numerous ways of transforming CO 2 to valuable products, viz., thermocatalysis, − biocatalysis, , radiolysis, , and photochemical (PC), − electrochemical (EC) − and photoelectrochemical (PEC) techniques. − The PC technique involves incorporating renewable solar energy for transforming CO 2 to produce valuable products. In contrast to the PEC process, it does not require any external potential bias and can be performed under ambient pressure and temperature conditions .…”