Highly Selective Photocatalytic Oxidation Biomass Valorization Over Nb₂O₅/g‐C₃N₄Heterojunction

Abstract

The selective biomass conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfurane (DFF) through photocatalysis is of immense importance and has attracted much interest recently. However, its selectivity and conversion are still limited at present due to the lack of efficient photocatalysts to controllably activate the alcohol hydroxyl groups. Herein, Nb2O5/g‐C3N4 type‐II heterojunction photocatalysts to restrain the over‐oxidation are developed, which successfully adjust the active oxygen species and enhance the separation and transfer of photoexcited carriers. The system achieves selective oxidation of HMF to DFF with high selectivity (>99%) and conversion (53%) via the inhibition of hydroxyl radicals (·OH) production arising from the decomposition of H2O2. Moreover, h+ is the main active species for photocatalytic selective oxidation of HMF, and ·O2− is the second for that. Herein, it offers an effective strategy to effectively improve the high‐selective conversion of biomass derivatives into high‐value‐added products.

α-Fe2O3/Nb2O5/C Nanorods for Selective Photoelectrocatalytic Oxidation of 5-Hydroxymethylfurfural under Solar Light

“…The Fe 2p spectrum in the α-Fe 2 O 3 /Nb 2 O 5 /C is shifted to a lower binding energy by 0.3 eV compared to pure α-Fe 2 O 3 . The XPS of Nb 3d in Figure b exhibits two peaks at about 207 eV (Nb 3d 5/2 ) and 209.7 eV (Nb 3d 3/2 ), respectively . However, these peaks deviate slightly from the analysis reported for pure Nb 2 O 5 , shifting toward the high binding energy by 0.4 eV.…”

“…The peaks at 718.9 and 733.7 eV are 41 The XPS of Nb 3d in Figure 3b exhibits two peaks at about 207 eV (Nb 3d 5/2 ) and 209.7 eV (Nb 3d 3/2 ), respectively. 42 However, these peaks deviate slightly from the analysis reported for pure Nb 2 O 5 , shifting toward the high binding energy by 0.4 eV. This implies that a strong chemical interaction exists between α-Fe 2 O 3 and Nb 2 O 5 to form a heterogeneous structure and that electron transfer from Nb 2 O 5 to α-Fe 2 O 3 makes Nb 2 O 5 hole-rich, which facilitates the oxidation reaction.…”

Light‐Emitting Diode Visible‐Light‐Driven Photocatalytic Redox Reactions in Nitrogen Oxide Removal Using β‐Bi2O3/Bi/g‐C3N4 Prepared by One‐Step In Situ Thermal Reduction Synthesis

“…The absorption peaks between 1242 and 1637 cm −1 were ascribed to the C–N heterocycle stretching vibration, and the absorption peak at 808 cm −1 was explained to the band breathing mode of the triazine units of g‐C 3 N 4 . [ 32 ] The peaks at 531 and 592 cm −1 were associated with the Bi–O vibration of BiO 6 units, while the band at 1391 cm −1 was assigned to the Bi–O stretching modes. [ 33,34 ] For BBC‐0.75, the peak intensities corresponding to g‐C 3 N 4 became weaker within 531–592 cm −1 at 808 and 1391 cm −1 because of the synergistic effect after the modification with β‐Bi 2 O 3 .…”

Sunlight-driven photocatalytic conversion of furfural and its derivatives

“…54,55 Li et al integrated Nb 2 O 5 to g-C 3 N 4 to obtain II-type Nb 2 O 5 /g-C 3 N 4 heterojunction. 56 The experimental results showed an improved separation efficiency of photogenerated e − and h + due to the existence of the built-in electric field in the heterojunction, thus boosting photocatalytic reaction performance. In addition, the energy band structure can be adjusted by the formation of the heterojunction.…”