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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]

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]

[Display omitted] • Novel Au/Ar-CN photocatalyst was designed for the photocatalytic CO 2 reduction. • Intramolecular modifications regulate the local π-electron distribution of CN. • The Schottky junctions modulate space charge transfer and provide CO 2 RR sites. • Au/Ar-CN performs high photocatalytic evolution CO rate of 32.03 μmol·g–1·h–1. Polymeric carbon nitride (CN) is one of the most prospective non-metallic catalysts at present, yet its photocatalytic activity is unsatisfactory mainly due to the poor intramolecular charge carrier separation efficiency originated form its special electronic structure. Herein, we demonstrate a synergistic strategy to improve the charge carriers transfer and separation efficiency of CN synchronously by extending the π-conjugated system via incorporation of O-containing aromatic ring in the CN skeleton (Ar-CN) and constructing a Schottky junction via decoration of Au nanoparticles (Au Nps). The introduced O-containing aromatic ring can create a local asymmetry, delocalize the π-conjugated system of CN, and thus promote the in-plane charge transport of CN, while the formed loading of Au Nps can further promote interlayer charge transfer efficiency of Ar-CN. The optimized 3 %Au/Ar-CN photocatalyst exhibits a high photocatalytic CO 2 activity with a CO yield of 32.03 μmol·g−1·h−1, which is higher than those of CN (2.38 μmol·g−1·h−1) and Ar-CN (6.42 μmol·g−1·h−1). This study provides a feasible co-modification strategy to enhance the charge transfer and photocatalytic activity of CN by extending the π-conjugation system and constructing Schottky junctions. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2D/2D MgAl LDO/N v -CN photocatalysts were designed for CO 2 RR. • The catalyst exhibits superior photocatalytic CO 2 RR activity. • The catalysts achieved the CO evolution rate of 20.47 µmol·g−1·h−1. • The synergistic of defects and Lewis sites promote CO 2 photoreduction activity. Conversion of CO 2 to CO from solar energy on semiconductors is a promising route to renewable energy, but their practicality is limited by the poor adsorption and activation of CO 2 on the semiconductor surface and the low utilization of photovoltaic carriers. Here, we construct a MgAl layered double oxide/nitrogen-deficient carbon nitride (MgAl LDO/N v -CN) nanosheets hybrid by in situ deposition of MgAl layered double hydroxide (MgAl LDH) on N v -CN nanosheets followed by subsequent calcination. The MgAl LDO serves as the surface-rich Lewis basic sites to effectively enhance adsorption of CO 2 and H 2 O, while the nitrogen defects can enhance the optical absorption of g-C 3 N 4 and improve the charge carrier separation. The optimal MgAl LDO/N v -CN has high photocatalytic activity for CO 2 reduction with a CO generation rate of 20.47 µmol·g−1·h−1 under visible light illumination, which is 6 times higher than that of bulk g-C 3 N 4. Our work highlights the significance of synergy of MgAl LDO Lewis base/acid sites and nitrogen vacancy defects in the design of efficient photocatalysts for CO 2 reduction. [ABSTRACT FROM AUTHOR]

• ZnIn 2 S 4 /KCa 2 Nb 3 O 10 nanosheet heterojunctions are constructed by in-situ solution-processed method. • The optimal sample shows significantly enhanced photocatalytic CO 2 reduction activity than bare ZnIn 2 S 4 and KCa 2 Nb 3 O 10. • The enhanced photocatalytic activity is ascribed to the improved charge separation efficiency of heterojunctions. ga1 Construction of heterojunctions with face-to-face contact is an excellent strategy for highly efficient photocatalytic CO 2 reduction system. Herein, ZnIn 2 S 4 /KCa 2 Nb 3 O 10 (ZnIn 2 S 4 /KCNO) 2D/2D nanosheet heterojunctions are fabricated via an in-situ solution-processed method, and the optimal 20%-ZnIn 2 S 4 /KCNO heterojunction shows a significantly enhanced photocatalytic activity with the CO production rate of 4.69 μmol g−1 h−1, which is about 12.31 and 1.95 times higher than that of bare ZnIn 2 S 4 and KCa 2 Nb 3 O 10 under simulated sunlight irradiation. The as-prepared ZnIn 2 S 4 /KCNO nanosheet heterojunctions exhibit tremendously improved charge transfer and separation efficiency. The ultrathin structure KCNO is conducive to the rapid transmission of photogenerated electrons, while the nanoflower-like structure ZnIn 2 S 4 is conducive to the full contact with the reactants to produce more protons, resulting in significantly boosted CO production performance. This work gives a new strategy to construct 2D/2D nanosheet heterojunctions for photocatalytic CO 2 conversion, which can offer significant inspirations for other 2D hybrid systems. [ABSTRACT FROM AUTHOR]