Photocatalytic CO₂ Conversion of M_0.33WO₃ Directly from the Air with High Selectivity: Insight into Full Spectrum-Induced Reaction Mechanism

Abstract

Natural photosynthesis is a solar light-driven process utilized by plants to convert CO 2 and water into carbohydrate molecules. The goal of artificial photosynthesis is the reduction of CO 2 directly from air into high purity value-added products at atmospheric pressure. However, its realization, combined with deep mechanism investigation, is a huge challenge. Herein, we demonstrate that hexagonal tungsten bronze M 0.33 WO 3 (M = K, Rb, Cs) series with {010} facets, prepared by a peculiar "water-controllable releasing" solvothermal method, showed excellent full spectrum (UV, visible, and NIR lights)-induced photocatalytic CO 2 reduction performance directly from the air at ambient pressure. Particularly, after 4 h near-infrared light irradiation, ca. 4.32% CO 2 in the air could be converted into CH 3 OH with 98.35% selectivity for Rb 0.33 WO 3 . The experiments and theoretical calculations unveiled that the introduced alkali metal atom occupied the tunnel of hexagonal structure and donated more free electrons to reconstruct the electronic structure of M 0.33 WO 3 , which can enhance the polaron transition, modify the energy band structure, selectively adsorb CO 2 rather than O 2 from the air, decrease the activation energy of CO 2 reaction, and finally make the effective CO 2 reduction in the air a reality. This work may provide a new possibility for the practical application of artificial photosynthesis.

Tungsten bronze Cs0.33WO3 nanorods modified by molybdenum for improved photocatalytic CO2 reduction directly from air

“…Taking advantage of this peculiar structure, M 0.33 WO 3 showed an outstanding photocatalytic CO 2 reduction activity, much higher than W 18 O 49 and WO 3 [31]. This superiority stems from the enhanced light absorption, the additional number of active sites, reduced charge recombination, and CO 2 activation energy [31]. Based on the above research, adding more Mo into M 0.33 WO 3 crystals is predicted to significantly improve its photocatalytic CO 2 reduction performance compared with solely alkali metals and Moinduced counterparts.…”

“…More interestingly, our groups recently unveiled that incorporating alkali metal ions into reduced WO 3 formed unique hexagonal tungsten bronze (M 0.33 WO 3 , M=K, Rb, Cs), in which the alkali metal ions were found at the hexagonal tunnel of crystal and formed weak chemical bonds with W and O. Taking advantage of this peculiar structure, M 0.33 WO 3 showed an outstanding photocatalytic CO 2 reduction activity, much higher than W 18 O 49 and WO 3 [31]. This superiority stems from the enhanced light absorption, the additional number of active sites, reduced charge recombination, and CO 2 activation energy [31].…”

Dispersed Nickel Cobalt Oxyphosphide Nanoparticles Confined in Multichannel Hollow Carbon Fibers for Photocatalytic CO2 Reduction

“…[1] Among the proposed CO 2 fixation strategies,s olar-driven photocatalytic CO 2 reduction is promising for generating valuable carbon fuels, [2,3] which thus can simultaneously alleviate climate changes and provide renewable energy.I ndeed, there has been notable progress for photocatalytic CO 2 reduction during the past several decades. [4][5][6][7][8] However,t he design and construction of efficient photocatalytic materials made of affordable elements are still highly desirable to achieve the goal of artificial photosynthesis for sustained solar-to-carbon fuel conversion.…”

Two-dimensional gersiloxenes with tunable bandgap for photocatalytic H2 evolution and CO2 photoreduction to CO

“…Obviously, the concentration of oxygen vacancies in HGeSiOH is higher than that of GeH and Si 6 H 3 (OH) 3 . The presence of surface oxygen vacancy defects leads to electron enrichment, which enhances the activation of CO 2 molecules, thereby further promoting CO 2 reduction 58,59 .…”