Photocatalytic Conversion of Diluted CO₂ into Tunable Syngas via Modulating Transition Metal Hydroxides

Abstract

The conversion of diluted CO 2 into tunable syngas via photocatalysis is critical for implementing CO 2 reduction practically, although the efficiency remains low. Herein, we report the use of graphene-modified transition metal hydroxides, namely, Ni X Co 1−X -GR, for the conversion of diluted CO 2 into syngas with adjustable CO/H 2 ratios, utilizing Ru dyes as photosensitizers. The Ni(OH) 2 -GR cocatalyst can generate 12526 μmol g −1 h −1 of CO and 844 μmol g −1 h −1 of H 2 , while the Co(OH) 2 -GR sample presents a generation rate of 2953 μmol g −1 h −1 for CO and 10027 μmol g −1 h −1 for H 2 . Notably, by simply altering the addition amounts of nickel and cobalt in the transition metal composite, the CO/H 2 ratios in syngas can be easily regulated from 18:1 to 1:4. Experimental characterization of composites and DFT calculations suggest that the differing adsorption affinities of CO 2 and H 2 O over Ni(OH) 2 -GR and Co(OH) 2 -GR play a significant role in determining the selectivity of CO and H 2 products, ultimately affecting the CO/H 2 ratios in syngas. Overall, these findings demonstrate the potential of graphene-modified transition metal hydroxides as efficient photocatalysts for CO 2 reduction and syngas production.

Rationally designed dual cocatalysts on ZnIn2S4 nanoflowers for photoredox coupling of benzyl alcohol oxidation with H2 evolution

“…S4c†), it can be inferred that the peak intensity of oxygen functional groups in ZIS–GR–Ni 2 P is lower, indicating the effective reduction of GO during the process of hydrothermal synthesis. 29,43,44 As depicted in Fig. 2c, the peaks of Zn in ZIS at 1045.2 eV and 1022.2 eV correspond to Zn 2p 1/2 and Zn 2p 3/2 , respectively, implying the presence of Zn 2+ .…”

Uncalcined Zn/Al Carbonate LDH and Its Calcined Counterpart for Treating the Wastewater Containing Anionic Congo Red Dye

“…Certain adsorbents are prohibitively expensive, challenging to dispose of, or excessively re-generable to be utilized on a large scale. In this context, a category of anionic clays referred to as layered double hydroxides has demonstrated efficacy as adsorbents for the elimination of numerous anionic impurities [38,39].…”