The n-π^(*) electronic transition in polymeric carbon nitride(PCN)can remarkably harvest visible light,which thus potentially promotes the photocatalytic hydrogen H2 generation.However,awaking the n-π^(*) lectronic ...The n-π^(*) electronic transition in polymeric carbon nitride(PCN)can remarkably harvest visible light,which thus potentially promotes the photocatalytic hydrogen H2 generation.However,awaking the n-π^(*) lectronic transition has proven to be a grand challenge.Herein,we reported on the awakening of n-π^(*) electronic transition by microwave thermolysis of urea pellet,which yielded the PCN with absorption edge of 600 nm,near 140 nm red-shift from 460 nm of pristine PCN.The n-π^(*) electronic transition endows PCN with an increased photocata lytic H_(2) generation,with a highest H_(2) rate of 61.7μmol h^(-1) under visible light exposure,which is near 6 times higher than that by using the PCN from the thermolysis of urea pellets in an electric furnace(10.6μmol h^(-1)).Furthermore,the n-π^(*) transition in PCN leads to the longest wavelength of 535 nm that can initiate H2 generation,remarkably longer than the absorption edge of pristine PCN(460 nm).This work manifests the advantages of microwave sintering route to awaken the n-π^(*) electronic transition in PCN for an increased photocata lytic performance.展开更多
Increasing the availability ofπ-electron in graphitic carbon nitride(g-C_(3)N_(4))can reduce the band gap and thus enhance the photocatalytic hydrogen(H_(2))generation activity upon exposure to visible light,However,...Increasing the availability ofπ-electron in graphitic carbon nitride(g-C_(3)N_(4))can reduce the band gap and thus enhance the photocatalytic hydrogen(H_(2))generation activity upon exposure to visible light,However,such strategy has not yet been largely applied to increase the H_(2)generation of g-C_(3)N_(4).Herein,we succes s fully increased the amount ofπ-electron in g-C_(3)N_(4)by incorporatingπ-electron-rich benzene rings through copolymerization of melamine and trimesic acid in air.The incorporation of benzene rings not only extends the light absorption of g-C_(3)N_(4)to 650 nm,but also improves the electrical conductivity due to delocalization ofπelectrons in benzene rings.As a result,a 3.4 times enhancement of photocatalytic H_(2)generation was achieved from the g-C_(3)N_(4)with benzene ring incorporation in comparing with that of pristine g-C_(3)N_(4).More interestingly,H_(2)generation still occurs under irradiation of the light ofλ≥490 nm,above the absorption edge of pristine g-C_(3)N_(4)(~460 nm),illustrating the positive effectiveness of incorporated benzene rings on enhancing the H_(2)generation capacity of g-C_(3)N_(4).The present work manifests the advantages of increasingπ-conjugated electrons on designing highly active g-C_(3)N_(4)photocatalysts.展开更多
Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photocatalytic hydrogen generation. However, the effective preparation of...Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photocatalytic hydrogen generation. However, the effective preparation of such photocatalysts has proven challenging.Herein, we report the facile synthesis of a novel noblemetal-free CdS/MoS/CoPi ternary photocatalyst via a visible light-induced synthesis route, in which MoSreduction cocatalysts were precisely grown on the two terminals of CdS nanorods, while CoPi oxidation cocatalysts were preferentially anchored onto the sidewalls of CdS nanorods. Such spatially isolated MoSand CoPi redox cocatalysts endow CdS nanorods with a rapid charge separation, which enhances their hydrogen generation activity. The CdS/MoS/CoPi photocatalyst with optimized CoPi amount achieves the highest Hgeneration rate of 206 μmol/h, which is 21 and 2 times higher than that achieved by using CdS alone(9.7 μmol/h) and CdS/MoS(105 μmol/h), respectively. The present work highlights the effectiveness of the spatial isolation of reduction and oxidation sites for efficient charge separation and thereby provides a promising strategy for the preparation of highly active photocatalysts.展开更多
基金financially supported by the National Natural Science Foundation of China (52072001, 51872003, U1832148 and U1932218)the Anhui Provincial Natural Science Foundation (1908085J21 and 1908085QB83)。
文摘The n-π^(*) electronic transition in polymeric carbon nitride(PCN)can remarkably harvest visible light,which thus potentially promotes the photocatalytic hydrogen H2 generation.However,awaking the n-π^(*) lectronic transition has proven to be a grand challenge.Herein,we reported on the awakening of n-π^(*) electronic transition by microwave thermolysis of urea pellet,which yielded the PCN with absorption edge of 600 nm,near 140 nm red-shift from 460 nm of pristine PCN.The n-π^(*) electronic transition endows PCN with an increased photocata lytic H_(2) generation,with a highest H_(2) rate of 61.7μmol h^(-1) under visible light exposure,which is near 6 times higher than that by using the PCN from the thermolysis of urea pellets in an electric furnace(10.6μmol h^(-1)).Furthermore,the n-π^(*) transition in PCN leads to the longest wavelength of 535 nm that can initiate H2 generation,remarkably longer than the absorption edge of pristine PCN(460 nm).This work manifests the advantages of microwave sintering route to awaken the n-π^(*) electronic transition in PCN for an increased photocata lytic performance.
基金financially supported by the National Natural Science Foundation of China(Nos.51872003 and 51572003)the University Natural Science Research Project of Anhui Province(No.KJ2017A299)+1 种基金the Anhui Provincial Natural Science Foundation(Nos.1908085J21 and 1908085QB83)the Research Start-up Fund of Anhui University(No.S020118002/011)。
文摘Increasing the availability ofπ-electron in graphitic carbon nitride(g-C_(3)N_(4))can reduce the band gap and thus enhance the photocatalytic hydrogen(H_(2))generation activity upon exposure to visible light,However,such strategy has not yet been largely applied to increase the H_(2)generation of g-C_(3)N_(4).Herein,we succes s fully increased the amount ofπ-electron in g-C_(3)N_(4)by incorporatingπ-electron-rich benzene rings through copolymerization of melamine and trimesic acid in air.The incorporation of benzene rings not only extends the light absorption of g-C_(3)N_(4)to 650 nm,but also improves the electrical conductivity due to delocalization ofπelectrons in benzene rings.As a result,a 3.4 times enhancement of photocatalytic H_(2)generation was achieved from the g-C_(3)N_(4)with benzene ring incorporation in comparing with that of pristine g-C_(3)N_(4).More interestingly,H_(2)generation still occurs under irradiation of the light ofλ≥490 nm,above the absorption edge of pristine g-C_(3)N_(4)(~460 nm),illustrating the positive effectiveness of incorporated benzene rings on enhancing the H_(2)generation capacity of g-C_(3)N_(4).The present work manifests the advantages of increasingπ-conjugated electrons on designing highly active g-C_(3)N_(4)photocatalysts.
基金financially supported by National Natural Science Foundation of China(22102002,52072001,51872003)Natural Science Foundation of Anhui Province(2108085QE192)。
文摘Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photocatalytic hydrogen generation. However, the effective preparation of such photocatalysts has proven challenging.Herein, we report the facile synthesis of a novel noblemetal-free CdS/MoS/CoPi ternary photocatalyst via a visible light-induced synthesis route, in which MoSreduction cocatalysts were precisely grown on the two terminals of CdS nanorods, while CoPi oxidation cocatalysts were preferentially anchored onto the sidewalls of CdS nanorods. Such spatially isolated MoSand CoPi redox cocatalysts endow CdS nanorods with a rapid charge separation, which enhances their hydrogen generation activity. The CdS/MoS/CoPi photocatalyst with optimized CoPi amount achieves the highest Hgeneration rate of 206 μmol/h, which is 21 and 2 times higher than that achieved by using CdS alone(9.7 μmol/h) and CdS/MoS(105 μmol/h), respectively. The present work highlights the effectiveness of the spatial isolation of reduction and oxidation sites for efficient charge separation and thereby provides a promising strategy for the preparation of highly active photocatalysts.
