Rare-Earth Single-Atom La–N Charge-Transfer Bridge on Carbon Nitride for Highly Efficient and Selective Photocatalytic CO₂ Reduction

Abstract

Photocatalytic CO2 conversion into valuable solar fuels is highly appealing, but lack of directional charge-transfer channel and insufficient active sites resulted in limited CO2 reduction efficiency and selectivity for most photocatalytic systems. Herein, we designed and fabricated rare-earth La single-atoms on carbon nitride with La–N charge-transfer bridge as the active center for photocatalytic CO2 reaction. The formation of La single-atoms was certified by spherical aberration-corrected HAADF-STEM, STEM-EELS, EXAFS, and theoretical calculations. The electronic structure of the La–N bridge enables a high CO-yielding rate of 92 μmol·g–1·h–1 and CO selectivity of 80.3%, which is superior to most g-C3N4-based photocatalytic CO2 reductions. The CO production rate remained nearly constant under light irradiation for five cycles of 20 h, indicating its stability. The closely combined experimental and DFT calculations clearly elucidated that the variety of electronic states induced by 4f and 5d orbitals of the La single atom and the p–d orbital hybridization of La–N atoms enabled the formation of charge-transfer channel. The La–N charge bridges are found to function as the key active center for CO2 activation, rapid COOH* formation, and CO desorption. The present work would provide a mechanistic understanding into the utilization of rare-earth single-atoms in photocatalysis for solar energy conversion.

Revealing the Sudden Alternation in Pt@h‐BN Nanoreactors for Nearly 100% CO2‐to‐CH4 Photoreduction

“…For the development of efficient photocatalysts, scientists have done a lot of meaningful work. [ 12–14 ] Jiang et al. [ 15 ] reported that by accurately anchoring TiO 2 in two different molecular compartments of MIL‐101, a quantum efficiency of up to 11.3% was achieved, proving that the precise positioning of TiO 2 in the metal‐organic framework (MOF) system can effectively improve the material performance.…”

“…For the development of efficient photocatalysts, scientists have done a lot of meaningful work. [12][13][14] Jiang et al [15] reported that by accurately anchoring TiO 2 in two different molecular compartments of MIL-101, a quantum efficiency of up to 11.3% was achieved, proving that the precise positioning of TiO 2 in the metal-organic framework (MOF) system can effectively improve the material performance. Li et al [16] reported that through a top-down direct metal atomization method to prepare single atoms and the use of CO species to adjust the coordination environment, a high turnover number of 1493.5 could be achieved in CO 2 photoreduction process.…”

Erbium Single Atom Composite Photocatalysts for Reduction of CO2 under Visible Light: CO2 Molecular Activation and 4f Levels as an Electron Transport Bridge

“…[49] Reducing rare-earth nanomaterials to a single-atom scale, the unique structural characteristics of the rare-earth single atom might give them different or unexpected properties from the nanoscale homologs, which provides a new opportunity for efficient photocatalytic CO 2 reduction. [50,51] Here, erbium (Er) single atom composite photocatalysts were successfully constructed by in situ synthesis and chemisorption, respectively. Especially, Zn 2 GeO 4 :Er 3+ /g-C 3 N 4 obtained by in situ synthesis is not only more conducive to the tight junction of Zn 2 GeO 4 :Er 3+ and g-C 3 N 4 , but also more favorable for g-C 3 N 4 to anchor rare-earth atoms.…”

Urea-induced supramolecular self-assembly strategy to synthesize wrinkled porous carbon nitride nanosheets for highly-efficient visible-light photocatalytic degradation

“…5 However, the photocatalytic efficiency of bulk g-C 3 N 4 obtained by thermal polymerization of traditional precursors such as melamine, dicyandiamide and cyanamide is restricted by rapid recombination of photogenerated electron-hole pairs, marginal visible light absorption and small specic surface area. 6,7 In order to improve its photocatalytic performance, various methods have been developed, such as semiconductor coupling, 8,9 element doping [10][11][12] and nanostructure engineering. 13,14 To date, tremendous efforts have been devoted to design nanostructures of g-C 3 N 4 because the photocatalytic performance of g-C 3 N 4 depends strongly on its morphology.…”