Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the ma...Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the main catalyst,while Ti_(3)C_(2) MXene served as the co-catalyst.Experimental and theoretical results revealed that Ti_(3)C_(2) MXene introduced electron-rich unsaturated Ti sites,serving as highly active sites for both the adsorption and activation of N_(2) on the Ti_(3)C_(2)/TiO_(2) heterojunction.Furthermore,the 2D/2D Ti_(3)C_(2)/TiO_(2) heterostructure greatly promoted the directional separation and transfer of charge carriers,facilitated by the internal electric field.This structural feature enabled the spatial separation of the N_(2) reduction and H2 O oxidation half-reactions on the distinct surfaces of Ti_(3)C_(2)(001)and TiO_(2)(001),con-sequently reducing the reaction energy barrier for each respective process.The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photo-catalytic NRR activity.As a result,the optimized Ti_(3)C_(2)/TiO_(2) heterojunction exhibited a high NH_(3) produc-tion rate of 24.4μmol g−1 h−1 in the absence of sacrificial agents,representing a remarkable 12.8-fold increase compared to individual TiO_(2) Ns.This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism under-lying surface active sites in the photocatalytic NRR process.展开更多
Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas s...Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas sensing at room temperature.The distinctive advantages of 2D Ti_(3)C_(2)MXene,including high electrical conductivity,ample surface area,surface termination groups,and layer structure have garnered significant attention towards NO_(2)gas adsorption.Further,the compatible regularity of Ti_(3)C_(2)MXene at the interface of various semiconductors directed the development of potential room-temperature NO_(2)gas sensing devices.Further,the leveraging gas sensing(selectivity,response,and recovery)characteristics be-come increasing attention on Ti_(3)C_(2)MXene/semiconductor interfaces than pure Ti_(3)C_(2)MXene.Elaborative control on the depletion layer through the Schottky barrier formation distinguished the room tempera-ture NO_(2)gas sensing and led to the evolution of electrophilic NO_(2)gas molecule interaction.Remarkably,the great processability of Ti_(3)C_(2)MXene/semiconductor interface is sensitive to the low detection limit(LOD)of NO_(2)gas at parts per billion(ppb)conditions.On the other hand,this review demonstrates the room temperature optoelectronic NO_(2)gas sensing capabilities of Ti_(3)C_(2)-based composites for emphasiz-ing selectivity and recovery.Interestingly,the Ti_(3)C_(2)MXene/semiconductor composite builds immunity against the atmosphere humidity and achieves stable NO_(2)gas sensing.Finally,we have provided conclu-sions and key points to advance the research on room temperature NO_(2)gas sensing of Ti_(3)C_(2)integrated semiconductors.展开更多
As a substitute for synthetic ammonia under mild condition, electrocatalytic nitrogen reduction reaction(NRR) provides a hopeful approach for the development of ammonia. Nevertheless, the current development of NRR el...As a substitute for synthetic ammonia under mild condition, electrocatalytic nitrogen reduction reaction(NRR) provides a hopeful approach for the development of ammonia. Nevertheless, the current development of NRR electrocatalysts is far from enough and a systematic research is needed to gain a better improvement. This article presents that 2 D C_(3)N_(4)-NV with a large specific surface area and abundant nitrogen vacancies is prepared by a simple and feasible method, and used as a metal-free catalyst for electrocatalytic NRR. Experiment result and density functional theory(DFT) calculation reveal that nitrogen vacancies in 2 D C_(3)N_(4)-NV can act as an efficient active site for catalytic NRR, which is conducive to capturing and activating N_(2), lowering Gibbs free energy(DG) in reaction and inhibiting hydrogen evolution reaction(HER) at the same time. In addition, the larger specific surface area also makes more active site exposed, which is good for the contact between the electrolyte and the active site, thus enhancing its NRR activity. The electrocatalyst shows an excellent catalytic activity for NRR in 0.1 M HCl, including Faradaic efficiency of 10.96%, NH_(3) yields of 17.85 lg h^(-1) mg_(cat)^(-1)., and good stability(over 20 h).展开更多
基金supported by the National Natural Science Foundation of China(No.21773089)the Henan Center for Outstanding Overseas Scientist(No.GZS2024004).
文摘Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the main catalyst,while Ti_(3)C_(2) MXene served as the co-catalyst.Experimental and theoretical results revealed that Ti_(3)C_(2) MXene introduced electron-rich unsaturated Ti sites,serving as highly active sites for both the adsorption and activation of N_(2) on the Ti_(3)C_(2)/TiO_(2) heterojunction.Furthermore,the 2D/2D Ti_(3)C_(2)/TiO_(2) heterostructure greatly promoted the directional separation and transfer of charge carriers,facilitated by the internal electric field.This structural feature enabled the spatial separation of the N_(2) reduction and H2 O oxidation half-reactions on the distinct surfaces of Ti_(3)C_(2)(001)and TiO_(2)(001),con-sequently reducing the reaction energy barrier for each respective process.The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photo-catalytic NRR activity.As a result,the optimized Ti_(3)C_(2)/TiO_(2) heterojunction exhibited a high NH_(3) produc-tion rate of 24.4μmol g−1 h−1 in the absence of sacrificial agents,representing a remarkable 12.8-fold increase compared to individual TiO_(2) Ns.This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism under-lying surface active sites in the photocatalytic NRR process.
基金supported by the National Research Foundation of Korea(NRF)Grant funded by the Korea government(MSIT)(No.2019R1A2C1008746).
文摘Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas sensing at room temperature.The distinctive advantages of 2D Ti_(3)C_(2)MXene,including high electrical conductivity,ample surface area,surface termination groups,and layer structure have garnered significant attention towards NO_(2)gas adsorption.Further,the compatible regularity of Ti_(3)C_(2)MXene at the interface of various semiconductors directed the development of potential room-temperature NO_(2)gas sensing devices.Further,the leveraging gas sensing(selectivity,response,and recovery)characteristics be-come increasing attention on Ti_(3)C_(2)MXene/semiconductor interfaces than pure Ti_(3)C_(2)MXene.Elaborative control on the depletion layer through the Schottky barrier formation distinguished the room tempera-ture NO_(2)gas sensing and led to the evolution of electrophilic NO_(2)gas molecule interaction.Remarkably,the great processability of Ti_(3)C_(2)MXene/semiconductor interface is sensitive to the low detection limit(LOD)of NO_(2)gas at parts per billion(ppb)conditions.On the other hand,this review demonstrates the room temperature optoelectronic NO_(2)gas sensing capabilities of Ti_(3)C_(2)-based composites for emphasiz-ing selectivity and recovery.Interestingly,the Ti_(3)C_(2)MXene/semiconductor composite builds immunity against the atmosphere humidity and achieves stable NO_(2)gas sensing.Finally,we have provided conclu-sions and key points to advance the research on room temperature NO_(2)gas sensing of Ti_(3)C_(2)integrated semiconductors.
基金funded by the National Natural Science Foundation of China (21802058 and 21872066)the Fundamental Research Funds for the Central Universities (China, lzujbky-2020-42)the Natural Science Foundation of Gansu Province (20JR5RA225)。
文摘As a substitute for synthetic ammonia under mild condition, electrocatalytic nitrogen reduction reaction(NRR) provides a hopeful approach for the development of ammonia. Nevertheless, the current development of NRR electrocatalysts is far from enough and a systematic research is needed to gain a better improvement. This article presents that 2 D C_(3)N_(4)-NV with a large specific surface area and abundant nitrogen vacancies is prepared by a simple and feasible method, and used as a metal-free catalyst for electrocatalytic NRR. Experiment result and density functional theory(DFT) calculation reveal that nitrogen vacancies in 2 D C_(3)N_(4)-NV can act as an efficient active site for catalytic NRR, which is conducive to capturing and activating N_(2), lowering Gibbs free energy(DG) in reaction and inhibiting hydrogen evolution reaction(HER) at the same time. In addition, the larger specific surface area also makes more active site exposed, which is good for the contact between the electrolyte and the active site, thus enhancing its NRR activity. The electrocatalyst shows an excellent catalytic activity for NRR in 0.1 M HCl, including Faradaic efficiency of 10.96%, NH_(3) yields of 17.85 lg h^(-1) mg_(cat)^(-1)., and good stability(over 20 h).
