Spatial Decoupling of Redox Chemistry for Efficient and Highly Selective Amine Photoconversion to Imines

Abstract

Light-driven primary amine oxidation to imines integrated with H 2 production presents a promising means to simultaneous production of high-valueadded fine chemicals and clean fuels. Yet, the effectiveness of this strategy is generally limited by the poor charge separation of photocatalysts and uncontrolled hydrogenation of imines to secondary amines. Herein, a spatial decoupling strategy is proposed to isolate redox chemistry at distinct sites of photocatalysts, and CoP core−ZnIn 2 S 4 shell (CoP@ZnIn 2 S 4 ) coaxial nanorods are assembled as the proofof-concept photocatalyst. Directional and ultrafast carrier separation occurs between the CoP core and the ZnIn 2 S 4 shell, as confirmed by in situ X-ray photoelectron spectroscopy, surface photovoltage spectroscopy, and transient absorption spectroscopy analyses. Toward the photoconversion of model substrate benzylamine to N-benzylbenzaldimine, CoP@ZnIn 2 S 4 exhibits a 48-time higher production rate and >99% selectivity when compared to ZnIn 2 S 4 (ca. 20% selectivity), and the detailed reaction mechanism has been verified by in situ diffuse reflectance infrared Fourier transform spectroscopy.

Locally Asymmetric BiOBr for Efficient Exciton Dissociation and Selective O2 Activation toward Oxidative Coupling of Amines

“…The EPR signal of the DMPO-C 6 H 5 CH 2 ·NH adduct might have been masked by the stronger EPR signal of the DMPO-C 6 H 5 ·CHNH 2 adduct and thus could not be resolved. As the reaction proceeded, a new IR peak at 1668 cm –1 assigned to ν­(CN) of the benzyl imine intermediate emerged and subsequently evolved into 1677 cm –1 attributed to the ν­(CN) of BNI. , Meanwhile, the appearance of the N–H stretching vibration of NH 3 at 3448 cm –1 indicated the formation of ammonia along with NBI production. Notably, no characteristic IR peaks of CO vibrations were observed, suggesting this reaction did not involve a benzaldehyde intermediate …”

Atomically Dispersed Pt on CdS Nanosheets for Photocatalytic Evolution of H2 and 1,1-Diethoxyethane from Ethanol

“…In addition, it can be identified from biexponential function fits to the time-resolved PL that the average lifetime (84.69 ns) of Pt SS -CdS is shorter than that of CdS (95.50 ns; Figure d). The rather different lifetimes arise from both fast and slow contributions, indicating that Pt single atoms produce obvious trapping ability for photoexcited electrons. , On the other hand, the calculated charge separation rate ( k = 1/τ ave ) of Pt SS -CdS (1.18 × 10 7 s –1 ) is also larger than that of pristine CdS (1.05 × 10 7 s –1 ), verifying the positive role of Pt single atoms in retarding the charge recombination . The transient photocurrent response exhibits a 6.6-fold enhanced photocurrent intensity compared to that of CdS (Figure e).…”

“…49,50 On the other hand, the calculated charge separation rate (k = 1/τ ave ) of Pt SS -CdS (1.18 × 10 7 s −1 ) is also larger than that of pristine CdS (1.05 × 10 7 s −1 ), verifying the positive role of Pt single atoms in retarding the charge recombination. 51 The transient photocurrent response exhibits a 6.6-fold enhanced photocurrent intensity compared to that of CdS (Figure 5e). The electrochemical impedance spectra (EIS) measurements also depict that the semiarc radius is significantly decreased after photodepositing Pt single atoms, and the smaller fitted R ct for Pt SS -CdS (26.9 kΩ) in comparison to that for CdS (59.1 kΩ) corresponds to less charge transfer resistance (Table S6).…”

Photothermal Effect- and Interfacial Chemical Bond-Modulated NiOx/Ta3N5 Heterojunction for Efficient CO2 Photoreduction

“…These shifts suggest the likelihood of electron transfer from Ta 3 N 5 to NiO x . 33,34 Furthermore, the presence of an additional peak at 398.3 eV in the N 1s spectrum and an additional peak at 28.8 eV in the Ta 4f spectrum (Figure 2f) can be attributed to the N 1s sites of Ni− N species 35 and Ta 4f sites of Ta−O species, 36 respectively. This confirms the formation of Ni−N and Ta−O bonds in the catalyst.…”

“…Furthermore, upon analyzing the high-resolution XPS spectra of the N 1s and Ta 4p signals observed in the NiO x /Ta 3 N 5 heterostructure, positive shifts of 0.6 and 0.4 eV are evident in the binding energies of the N 1s and Ta 4p peaks within NiO x /Ta 3 N 5 , respectively, compared to those in Ta 3 N 5 (Figure e). These shifts suggest the likelihood of electron transfer from Ta 3 N 5 to NiO x . , Furthermore, the presence of an additional peak at 398.3 eV in the N 1s spectrum and an additional peak at 28.8 eV in the Ta 4f spectrum (Figure f) can be attributed to the N 1s sites of Ni–N species and Ta 4f sites of Ta–O species, respectively. This confirms the formation of Ni–N and Ta–O bonds in the catalyst.…”