Chemically Bonded α‐Fe₂O₃/Bi₄MO₈Cl Dot‐on‐Plate Z‐Scheme Junction with Strong Internal Electric Field for Selective Photo‐oxidation of Aromatic Alcohols

Abstract

Inferior contact interface and low charge transfer efficiency seriously restrict the performance of heterojunctions. Herein, chemically bonded α-Fe 2 O 3 / Bi 4 MO 8 Cl (M = Nb, Ta) dot-on-plate Z-scheme junctions with strong internal electric field are crafted by an in situ growth route. Experimental and theoretical results demonstrate that the internal electric field provides a powerful driving force for vectorial migration of photocharges between Bi 4 MO 8 Cl and α-Fe 2 O 3 , and the interfacial FeÀ O bond not only serves as an atomiclevel charge flow highway but also lowers the charge transfer energy barrier, thereby accelerating Z-scheme charge transfer and realizing effective spatial charge separation. Impressively, α-Fe 2 O 3 /Bi 4 MO 8 Cl manifests a significantly improved photocatalytic activity for selective oxidation of aromatic alcohols into aldehydes (Con. � 92 %, Sel. � 96 %), with a performance improvement of one to two orders of magnitude. This work presents atomic-level insight into interfacial charge flow steering.

Improving Interface Matching in MOF-on-MOF S-Scheme Heterojunction through π–π Conjugation for Boosting Photoelectric Response

“…Therefore, enhancing interfacial interaction to establish a distinct charge transport channel can be an effective solution to this bottleneck. Recent studies have shown that the formation of interfacial chemical bonds can serve as an atomic-level charge transport channel, but it is subject to elemental composition in the utilized semiconductors. − In comparison with chemical bond construction, enhancing intermolecular interaction through π–π conjugation , is well acknowledged to modulate the interfacial properties of organic semiconductors. , Owing to the unique electronic properties, the delocalized π-electrons are beneficial to carrier migration with small interface resistance. − In addition, the driving force induced by the interfacial built-in electric field also plays a key role in carrier diffusion, which is determined by the asymmetric charge distribution due to the rearrangement of Fermi levels ( E F ). − Advanced S-scheme carrier migration path exhibits superior interface dynamics to conventional type-II heterojunction. , However, the requirements of matched band structure and E F difference make the construction of S-scheme heterojunction challenging. Therefore, constructing superb 2D/2D S-scheme heterostructures with strong π–π conjugation and a giant built-in electric field at the interface is of great significance for boosting photoelectric response.…”

“…The surface potential of the heterojunctions was imaged using in situ Kelvin-probe force microscopy (KPFM) to further investigate the reason for the striking improvement in photoelectric performance through the construction of heterojunctions. ,, As presented in Figure a–c, the heterojunction exhibits a more pronounced three-dimensional (3D) surface potential distribution in darkness compared to CuTCPP­(Cu) and CuTCPP­(Fe). As indicated by the line-scanning curves, the surface potentials of CuTCPP­(Cu), CuTCPP­(Fe), and the heterojunction were 33 mV, 29 mV, and 62 mV, respectively.…”

Versatile synthesis of nano-icosapods via cation exchange for effective photocatalytic conversion of biomass-relevant alcohols

“…It is widely reported that the ˙CH(OH)Ph radical, which can be induced by the interaction between BA and h + , is often considered the key intermediate for selective photo-oxidation of alcohol into aldehyde. 58,59 Therefore, butylated hydroxytoluene (BHT), a commonly used carbon-centered free radical trapping reagent, was added to verify whether ˙CH(OH)Ph radicals are involved in the photocatalytic process. 59 Clearly, both the conversion of BA and H 2 evolution remain, suggesting the simultaneous participation of electrons and holes for BZD and H 2 production instead of ˙CH(OH)Ph radicals.…”

“…58,59 Therefore, butylated hydroxytoluene (BHT), a commonly used carbon-centered free radical trapping reagent, was added to verify whether ˙CH(OH)Ph radicals are involved in the photocatalytic process. 59 Clearly, both the conversion of BA and H 2 evolution remain, suggesting the simultaneous participation of electrons and holes for BZD and H 2 production instead of ˙CH(OH)Ph radicals. Furthermore, the carbon-centered free radicals have been further explored by the in situ EPR measurements with 5,5-dimethyl-1-pyrroline N -oxide (DMPO) as the spin-trapping regent to gain more information on the radical intermediate mechanism of the reaction (Fig.…”

“…Otherwise, the ˙CH(OH)Ph radical is gradually evolved over CdS icosapods with illumination and eventually trapped by DMPO, as evidenced by the characteristic signal peaks belonging to the DMPO-CH(OH)Ph adduct. 58,59…”