Green Thermo-Photo Catalytic Production of Syngas Using Pd/Nb–TiO₂ Catalysts

Abstract

In this contribution, a series of Pd-promoted Nb-doped titania samples were essayed in the gas-phase thermo-photo production of syngas from methanol/water mixtures. The Pd loading was tested in the 0.1 to 2.5 wt % range, leading to the presence of metallic nanoparticles under reaction. Reaction rates exceeding 52 mmol H2 g–1 h–1 and quantum efficiencies above 33% were obtained. The optimum sample having a 0.5 wt % of Pd provided an outstanding synergy between light and heat under reaction conditions, facilitating the boost of activity with respect to the single-source processes and achieving high selectivity to syngas. The spectroscopic analysis of the physico-chemical ground of the activity unveiled that the noble metal interaction with the Nb-doped anatase support triggers a cooperative effect, promoting the evolution of formic acid-type methanol-derived carbon-containing species and rendering a significant enhancement of syngas production. The proposed thermo-photo system is thus a firm candidate to contribute to the new green circular economy.

Advanced photocatalytic materials based degradation of micropollutants and their use in hydrogen production – a review

“…Nonetheless, their wide band gaps result in the absorption of only a small portion of the solar spectrum, severely limiting solar energy conversion efficiency. 122,123 Recent studies have demonstrated that introducing oxygen vacancies can lead to the creation of transition state energy levels, thereby narrowing the band gap and enhancing light absorption capacity. However, these oxygen vacancies can also introduce lattice distortions and alter spatial polarity, hindering the efficient transport of photogenerated carriers and reducing photocatalytic efficiency.…”