Work

Highly Selective CO 2 Conversion to CH 4 by a N-Doped HTiNbO 5 /NH 2 -UiO-66 Photocatalyst without a Sacrificial Electron Donor

Year: 2024

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Photocatalytic reduction of CO 2 to value-added chemicals is a promising technology for reducing atmospheric CO 2, but selectively producing a specific product still remains a great challenge. In this study, a Z-scheme heterojunction, N-doped HTiNbO 5 /NH 2 -UiO-66(Zr) (referred to as NH-NU), is developed to integrate the advantages of semiconductor photocatalysts and porous CO 2 adsorbents for CO 2 -to-CH 4 conversion. The NH-NU Z-scheme heterojunctions are fabricated via a simple one-pot solvothermal method, enabling the formation of a tight and uniform interface between the two phases, thereby facilitating the separation and transfer of the photoinduced charge carriers, as confirmed by TEM, EPR, electrochemical studies, and work functions. As a result, the as-prepared photocatalyst demonstrates a significant increase in selectivity for CH 4 production through CO 2 photoreduction, achieving a 10-fold enhancement compared to that of the pristine MOF, NH 2 -UiO-66. Moreover, there is no obvious decrease in the photocatalytic activity for CH 4 production across four consecutive cycles. In situ FT-IR spectroscopy and DFT calculations reveal that charge-enriched N-doped NH-NU-3 composites stabilize various C 1 intermediates in multistep elementary reactions, leading to superior selectivity in the CO 2 -to-CH 4 conversion process. This work establishes that efficient and selective heterogeneous catalytic processes can be achieved through the stabilization of reaction intermediates by designing suitable Z-scheme heterojunctions.

Source: JACS Au

DOI: 10.1021/jacsau.4c00998