Nb–O–C Charge Transfer Bridge in 2D/2D Nb₂O₅/g‐C₃N₄ S‐Scheme Heterojunction for Boosting Solar‐Driven CO₂ Reduction: In Situ Illuminated X‐Ray Photoelectron Spectroscopy Investigation and Mechanism Insight

Abstract

Although the construction of heterojunction photocatalysts is a promising way to achieve outstanding photocatalytic activities, a 2D heterojunction which possesses strong chemical bonding and appropriate interfacial contact toward efficient artificial photosynthesis is still a challenge. Herein, 2D/2D Nb2O5/g‐C3N4 S‐scheme heterojunction photocatalysts are successfully fabricated by a convenient in situ calcination route derived from niobic acid/urea precursor for the gas–solid CO2 reduction reaction. Under simulated solar irradiation, the total yield of C1 products (CH4 and CO) obtained on the optimized sample NOCN‐5 are 6.7 times and 5.3 times that over pristine Nb2O5 and g–C3N4 nanosheets, respectively, without sacrificial agent or cocatalysts. The enhanced performances of CO2 photoreduction might be attributed to the unique Nb─O─C chemical bonds induced charge transfer bridge, face‐to‐face contact, and the efficient S‐scheme transfer path of photoinduced electron–hole pairs, which is confirmed by in situ illuminated X‐ray photoelectron spectroscopy and density functional theory calculation. This work will provide a promising strategy for constructing S‐scheme heterojunction systems for efficient artificial photosynthesis reactions toward carbon neutrality.

Unveiling S‐Scheme Charge Transfer Pathways in In2S3/Nb2O5 Hybrid Nanofiber Photocatalysts for Low‐Concentration CO2 Hydrogenation

“…[17][18][19][20][21][22] The main limiting factors of CO 2 conversion efficiency are as follows: 1) Mismatch between semiconductor bandgap and spectral absorption energy; 2) Efficacy of photogenerated electron-hole pairs in carrier separation is low; 3) Reverse reactions and diversity of products will occur in the process of CO 2 reduction. [23][24][25][26][27] In addition, the competition between the reduction of water molecules to hydrogen and the reduction of CO 2 to hydrocarbons in artificial photosynthesis is inevitable. [28][29][30][31][32] At the same time, it is urgent to develop new photocatalysts with high activity, high selectivity, and high stability.…”

Boosting photocatalytic CO2 conversion using strongly bonded Cu/reduced Nb2O5 nanosheets

“…5A, the pristine Nb 2 O 5 sample exhibits two subpeaks at 210.8 and 208.6 eV that are associated with the 3d5/2 and 3d3/2 states of Nb 5+ . 35,36 Following the reduction, the positions of the Nb 3d move to lower binding energies, namely 210.5 and 207.8 eV, as a result of chemical reduction of Nb 2 O 5 nanosheets. 37,38 A lower-energy Nb valence band was formed as a result of the binding energies shifting to the lower side, supporting the reduction of Nb 2 O 5 .…”

Interface Engineering in 2D/2D Heterogeneous Photocatalysts

“…Simultaneously, the solid interfacial interaction and great coupled interfaces of 2D/2D heterojunctions results in spatial charge separation and charge recombination suppression. [208,[217][218][219] A face-to-face 2D/2D ZnIn 2 S 4 / MoSe 2 heterolayered hybrids with strong interface coupling were synthesized from exfoliated ZnIn 2 S 4 ultrathin nanosheets with MoSe 2 through unconstrained electrostatic coupling (Figure 9b). [208] The ZnIn 2 S 4 /MoSe 2 performs superior visiblelight-driven hydrogen evolution activity of 6454 µmol g −1 h −1 than bulk ZnIn 2 S 4 , ZnIn 2 S 4 /1%Pt, and ZnIn 2 S 4 /1%MoS 2 , indicating that the coupling with MoSe 2 is better than the addition of Pt and MoS 2 as the cocatalyst to some extent (Figure 9c).…”