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.

No abstract

No abstract

Sluggish charge kinetics and low CO 2 affinity seriously limit the photocatalytic CO 2 reduction reaction. Herein, the simultaneous promotion of charge transfer and CO 2 activation over two-dimensional (2D) WO 3 nanosheets is achieved by coupling surface C-doping and oxygen vacancy. The surface-doped C atoms reconstruct the atomic surface of WO 3 by extracting oxygen lattice to generate the intimate oxygen vacancy (C−OV coordination) as the active center, which facilitates the CO 2 adsorption/activation, thus inducing the formation *CO 2 species. As a charge delivery channel, an exclusive W−O−C covalent bond formed by C−OV coordination could enhance the electron transfer. As a result, the as-designed catalyst exhibits 85.8% selectivity for CO 2 photoreduction to CO under the gas−solid phase reaction, with a yield rate of 23.2 μmol g −1 h −1 and a stable long-term reactivity over 24 h. Moreover, the in situ DRIFTS and DFT results reveal that this specific C−OV coordination enables the spontaneous CO 2 activation and proton-coupled electron transfer to guarantee the sustained formation of *COOH and, thus, smooth the photocatalytic CO 2 reduction reaction. This work develops a feasible strategy for electronic structure modification of photocatalysts with doping-induced oxygen vacancy to boost CO 2 activation and photoreduction.

No abstract

The co-generation of C-doping and oxygen vacancies (OVs) in Bi2WO6 nanosheets was achieved by a graphene oxide-mediated hydrothermal method. The photocatalytic performance was highly promoted in NO removal with the synergistic effects of C-doping and OVs.

Dry reforming of methane (DRM), which involves the activation of inert CH bonds and CO bonds, at mild conditions is a tremendous challenge. The sluggish mobility of oxygen during the reaction is known as a key issue causing low activity and poor stability of catalysts by the coke formation. Herein, a novel Cu-CNN/Pd-BDCNN photocatalyst that is made up of "Cu-nanoparticle-loaded g-C 3 N 4 nanosheets" and "Pd-nanoparticle-loaded boron-doped nitrogen-deficient g-C 3 N 4 nanosheets" is reported. The existing dual-reaction-sites benefit the reactive oxygen intermediates participate in the reaction directly without distant migration. The in situ characterizations and density functional theory calculations reveal a newly dual reaction pathway through simultaneous dehydrogenation of methoxy and methyl intermediates, and demonstrate the importance of metal loading, which promote the CO 2 and CH 4 activation from both aspects of thermodynamics and kinetics. The optimized Cu-CNN/Pd-BDCNN photocatalyst displays an excellent syngas formation rate of over 800 µmol g −1 h −1 with H 2 /CO = 1 and splendid stability in continuous flow reaction under 300 mW cm −2 xenon lamp irradiation at room temperature. The "dual-site" and "dual-path" strategy shed light on the design of effective photocatalysts for methane dry reforming.

Inefficient charge separation and insufficient surface catalytic sites remain the main impediment in developing highly efficient and selective catalysts for CO2 photoreduction. Surface defect is effective, but its function is...