A new approach to enhance photocatalytic nitrogen fixation performance via phosphate-bridge: a case study of SiW12/K-C3N4

Formation of BNC Coordination to Stabilize the Exposed Active Nitrogen Atoms in g‐C3N4 for Dramatically Enhanced Photocatalytic Ammonia Synthesis Performance

“…To date, varieties of catalysts, including BiOBr nanosheets, MXene‐derived TiO 2 @C/g‐C 3 N 4 , gold nanoparticles/black Si/Cr and other catalysts,3,9–12 have been developed and investigated for photo(electro)catalytic nitrogen reduction reaction (NRR), indicating high catalytic performance. As a class of metal‐free polymer semiconductor photocatalyst, graphitic carbon nitride (g‐C 3 N 4 ) possesses many advantages,13 such as low cost, abundance, superior visible‐light activity and high chemical/photochemical stability, exhibiting great potential for photocatalytic NRR 5,14. However, several issues are still existent associated with the NRR using the g‐C 3 N 4 ‐based photocatalyst: i) If the exposed active N atoms (e.g., edge or amino N atoms) in g‐C 3 N 4 will participate in the hydrogenation reaction during photocatalytic NRR, thus contributing the NH 3 formation?15 ii) If these N atoms can participate in the NH 3 formation during photocatalytic NRR, are there effective ways to stabilize them, and concurrently endow new catalytic active sites for N 2 adsorption, activation, and hydrogenation?…”

Mg−O‐Bridged Polypyrrole/g‐C3N4 Nanocomposites as Efficient Visible‐Light Catalysts for Hydrogen Evolution

“…[31,32] In addition, there is often a certain number of surfaceh ydroxyl groups on g-C 3 N 4 nanosheets,w hich may be unfavorable for its connections with another polymer.U nfortunately,t his is often neglected. In terms of this issue, it is feasible to introduce electronic bridges with multi-hydroxyl groups such as H 3 PO 4 (PÀOb ridges) [33] and Al(OH)n (AlÀObridges), [34] to effectively connectg-C 3 N 4 and another conductive polymer throughh ydrogen bonding. Therefore, it is very meaningfult of abricate closely contacted g-C 3 N 4 -based polymer nano-heterojunctions with proper electronic bridges for efficient visible-light-drivenH 2 evolution by promoting the charge transfer and separation.…”

Photocatalytic Fixation of Molecular Nitrogen in Systems Based on Graphite-Like Carbon Nitride: a Review

“…The maximum rate of NH 4 + formation holes was 0.78 mg/h×g PC (Table 3) under the action of visible light on this photocatalyst when using ethanol as an acceptor, which is almost an order of magnitude higher than in the presence of the individual components due to more efficient separation and transport of photogenerated charges promoted by the formation of the Bi 2 MoO 6 /g-C 3 N 4 heterojunction. The SiW 12 /K-g-C 3 N 4 composite, obtained by combining 12-silico-tungstic acid (SiW 12 ) and phosphated, potassium-modified GCN, containing a significant number of nitrogen vacancies and cyano groups, proved to be an active photocatalyst for nitrogen fixation in aqueous solutions in the absence of any sacrificial donor [134]. Ammonium ions were formed with the participation of SiW 12 /K-g-C 3 N 4 under the action of light at a rate of 6.35 mg/h×g PC (Table 4), which is 12 times faster than for K-g-C 3 N 4 .…”