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A novel bimetallic CoMoB-coupled carbon nitride with dual moiety defects (CN-TH 3/3) Schottky junction photocatalyst (CoMoB/CN-TH 3/3) was designed for photocatalytic nitrogen fixation. [Display omitted] • A novel CoMoB/(CN-TH 3/3) Schottky junction photocatalyst was designed for photocatalytic NRR. • Both of the intralayer exciton characteristics and the visible light adsorption capacity were altered. • The synergistic effect of CoMoB and CN-TH 3/3 accelerated charge transfer and enhanced the N 2 adsorption and activation. • The photocatalytic NRR performance of optimum CoMoB/CN-TH 3/3 is 6.2 times higher than CN. The sustainable generation of ammonia by photocatalytic nitrogen fixation under mild conditions is fascinating compared to conventional industrial processes. Nevertheless, owing to the low charge transfer efficiency, the insufficient light absorption capacity and limited active sites of the photocatalyst cause the difficult adsorption and activation of N 2 molecules, thereby resulting in a low photocatalytic conversion efficiency. Herein, a novel bimetallic CoMoB nanosheets (CoMoB) co-catalyst modified carbon nitride with dual moiety defects (CN-TH 3/3) Schottky junction photocatalyst is designed for photocatalytic nitrogen reduction reaction (NRR). The photocatalytic nitrogen reduction rate of the optimized CoMoB/CN-TH 3/3 photocatalyst is 4.81 mM·g−1·h−1, which is 6.2 and 2.2 times higher than carbon nitride (CN) (0.78 mM·g−1·h−1) and CN-TH 3/3 (2.21 mM·g−1·h−1), respectively. The excellent photocatalytic NRR performance is ascribed not only to the introduction of dual moiety defects (cyano and cyanamide groups) that extends the visible light absorption range and promotes exciton polarization dissociation, but also to the formation of interfacial electric field between CoMoB and CN-TH 3/3 , which effectively facilitates the interfacial charge transfer. Thus, the synergistic interaction between CN-TH 3/3 and CoMoB further increases the electron numble of CoMoB active sites, which effectively strengthens the adsorption and activation of N 2 and weakens the N N triple bond, thereby enhancing the photocatalytic NRR activity. This work highlights the introduced dual moiety defects and bimetallic CoMoB co-catalyst to synergistically enhance the photocatalytic nitrogen reduction performance. [ABSTRACT FROM AUTHOR]

[Display omitted] The inherent electron localized heptazine structure of carbon nitride (CN) derived from intrinsic tertiary N (N 3C) bridging structure makes the photogenerated charge separation rather difficult, which severely limits photocatalytic CO 2 activity of CN. Therefore, modulation of N 3C bridging structure of CN is highly desirable to enhance the charge separation efficiency of CN. Herein, we reported a novel thiophene-bridged CN (BTCN) with intramolecular donor-π-acceptor (D-π-A) systems synthesized by nucleophilic substitution and Schiff base reaction to improve the photogenerated charge separation efficiency. The experimental and density functional theory (DFT) results indicate that this BTCN exhibits a high π-electron delocalization range and enhanced photogenerated charge transfer efficiency, which mainly account for the enhanced photocatalytic activity. The optimal BTCN photocatalyst exhibits enhanced charge separation efficiency and higher photocatalytic CO 2 reduction activity with a CO yield of 23.02 μmol·g−1·h−1, which was higher than those of CN and edge-modified CN (ETCN) counterpart. This work highlights the importance of regulation of π-electron delocalization for the design of highly active CN photocatalysts via the rational substitution of N 3C bridging structure with π-spacer molecular linkages for photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] Photo-chemical conversion of CO 2 into solar fuels by photocatalysts is a promising and sustainable strategy in response to the ever-increasing environmental problems and imminent energy crisis. However, it is unavoidably impeded by the insufficient active site, undesirable inert charge transfer and fast recombination of photogenerated charge carriers on semiconductor photocatalysts. In this work, all these challenges are overcome by construction of a novel defect-engineered Z-scheme hybrid photocatalyst, which is comprised of three-dimensional (3D) BiOBr nanoflowers assembled by nanosheets with abundant oxygen vacancies (BiOBr-V O) and two-dimensional (2D) HNb 3 O 8 nanosheets (HNb 3 O 8 NS). The special 3D-2D architecture structure is beneficial to preventing photocatalyst stacking and providing more active sites, and the introduced oxygen vacancies not only broaden the light absorption range but also enhance the electrical conductivity. More importantly, the constructed Z-scheme photocatalytic system could accelerate the charge carriers transfer and separation. As a result, the optimal BiOBr-V O /HNb 3 O 8 NS (50%-BiOBr-V O /HNb 3 O 8 NS) shows a high CO production yield of 164.6 μmol·g−1 with the selectivity achieves to 98.7% in a mild gas-solid system using water as electron donors. Moreover, the BiOBr-V O /HNb 3 O 8 NS photocatalyst keeps high photocatalytic activity after five cycles under the identical experimental conditions, demonstrating its excellent long-term durability. This work provided an original strategy to design a new hybrid structure photocatalyst involved V O s, thus guiding a new way to further enhance CO 2 reduction activity of photocatalyst. [ABSTRACT FROM AUTHOR]

A Bi/HNb 3 O 8 -Vo hybrid photocatalyst was designed by a simple two-step method. Through the synergistic effect of oxygen vacancies and Bi nanoparticles on the catalyst surface, the electron-hole complexation rate was reduced, and the adsorption and activation of N 2 was enhanced. [Display omitted] Due to the high stability of the N 2 molecule and the low charge separation efficiency, the photocatalytic reduction of N 2 to high-value chemicals (NH 3) under mild conditions remains a great challenge. Herein, a composite photocatalyst (Bi/HNb 3 O 8 -Vo nanosheets) with Bi nanoparticles modified the HNb 3 O 8 -Vo nanosheets are designed for the conversion of N 2 into NH 3. In this design, the introduction of oxygen vacancies on the catalyst surface facilitates the formation of defective energy levels within the band gap of HNb 3 O 8 -Vo NS, which promotes the absorption of visible light, and enhances the charge carrier transport and separation. Bi nanoparticles co-catalyst not only facilitates the separation and migration of photogenerated charges, but also acts as reaction sites to adsorb and activate N 2 molecule. Consequently, the optimized 5 % Bi/HNb 3 O 8 -Vo photocatalysts show a NH 3 yield of 372.7 μmol/L g−1h−1 under full spectral irradiation without sacrificial agent, which is much higher than that of HNb 3 O 8 NS (92.2 μmol/L g−1h−1). This work provides a new way for the design of efficient N 2 reduction photocatalysts through the synergistic effect of surface vacancies and metal co-catalysts. [ABSTRACT FROM AUTHOR]

A Bi/HNb 3 O 8 -Vo hybrid photocatalyst was designed by a simple two-step method. Through the synergistic effect of oxygen vacancies and Bi nanoparticles on the catalyst surface, the electron-hole complexation rate was reduced, and the adsorption and activation of N 2 was enhanced. [Display omitted] Due to the high stability of the N 2 molecule and the low charge separation efficiency, the photocatalytic reduction of N 2 to high-value chemicals (NH 3) under mild conditions remains a great challenge. Herein, a composite photocatalyst (Bi/HNb 3 O 8 -Vo nanosheets) with Bi nanoparticles modified the HNb 3 O 8 -Vo nanosheets are designed for the conversion of N 2 into NH 3. In this design, the introduction of oxygen vacancies on the catalyst surface facilitates the formation of defective energy levels within the band gap of HNb 3 O 8 -Vo NS, which promotes the absorption of visible light, and enhances the charge carrier transport and separation. Bi nanoparticles co-catalyst not only facilitates the separation and migration of photogenerated charges, but also acts as reaction sites to adsorb and activate N 2 molecule. Consequently, the optimized 5 % Bi/HNb 3 O 8 -Vo photocatalysts show a NH 3 yield of 372.7 μmol/L g−1h−1 under full spectral irradiation without sacrificial agent, which is much higher than that of HNb 3 O 8 NS (92.2 μmol/L g−1h−1). This work provides a new way for the design of efficient N 2 reduction photocatalysts through the synergistic effect of surface vacancies and metal co-catalysts. [ABSTRACT FROM AUTHOR]

The artificially Z-scheme heterojunctions between WO 3 nanosheet and SnNb 2 O 6 nanosheet with strongly coupled heterointerfaces were successfully constructed via a simple hydrothermal coassembly method. Transmission electron microscopy (TEM) and high-resolution TEM proved that an intimate contact interface was formed. The synthesized heterojunctions exhibites enhanced photodegradation efficiency for Rhodamine B under irradiation of visible light, and the highest reaction rate over 30%-WO 3 /SnNb 2 O 6 nanosheet heterojunctions is about 4.7-fold and 2-fold higher than that of pristine WO 3 and SnNb 2 O 6 , respectively. Such a considerable improvement could be mainly attributed to the rapid migration of the photo-induced e − /h + pairs through the nanosheets-coupled heterojunction interfaces. A possible directly Z-scheme charge transfer mechanism was proposed for the elimination of organic contaminants under irradiation of visible light. This work may furnish new insights into development of novel 2D/2D nanosheet heterojunctions with the enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]