Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3...Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3)N_(4)(N,S-g-C_(3)N_(4))is elaborately designed on the basis of theoretical predictions of first-principle density functional theory(DFT).The calculated Gibbs free energy of adsorbed hydrogen(ΔGH∗)for N,S-g-C_(3)N_(4) at the N-doping active sites is extremely close to zero(0.01 eV).Inspired by the theoretical predictions,the N,S-g-C_(3)N_(4) is successfully fabricated through ammonia-rich pyrolysis synthesis strategy,in which ammonia is in-situ obtained by pyrolyzing melamine.Subsequent characterizations indicate that the N,S-g-C_(3)N_(4) possesses high specific surface area,outstanding light utilization,good hydrophilicity,and efficient carrier transfer efficiency.Consequently,the N,S-g-C_(3)N_(4) displays an extremely high H2 evolution rate of 8269.9μmol g−1 h−1,achieves an apparent quantum efficiency(AQE)of 3.24%,and also possesses outsatnding durability.Theoretical calculations further demonstrate that N and S dopants can not only introduce doping energy level to reduce the band gap,but also induce charge redistribution to facilitate hydrogen adsorption,thus promoting the photocatalytic HER process.Moreover,femtosecond transient absorption(fs-TA)spectroscopy further corroborates the efficient photogenerated carrier transport of N,S-g-C_(3)N_(4).This research highlights a promising and reliable strategy to achieve superior photocatalytic activity,and exhibits significant guidance for precise designing high-efficiency photocatalysts.展开更多
The development of catalysts that can efficiently separate both bulk and interface charges is crucial for conversion and utilization of solar energy.In this study,a homo-heterojunction was fabricated by combin-ing twi...The development of catalysts that can efficiently separate both bulk and interface charges is crucial for conversion and utilization of solar energy.In this study,a homo-heterojunction was fabricated by combin-ing twinned-Cd_(0.5)Zn_(0.5)S(T-CZS)and Ni_(3)(PO_(4))_(2)with crystalline water(NiPO)using a solvent evaporation strategy for efficient photocatalytic H_(2)evolution in water containing degradable plastics.The bulk phase of T-CZS consists of wurtzite Cd_(0.5)Zn_(0.5)S(WZ-CZS)and zinc blende Cd_(0.5)Zn_(0.5)S(ZB-CZS),they exhibit a slight difference in energy range and can form S-scheme homojunction,while NiPO and T-CZS constitute the S-scheme heterojunction,they work together to promote the separation of bulk and interface charges.This double S-scheme homo-heterojunction achieves a hydrogen evolution rate(rH_(2))of 73.2 mmol h−1 g−1 over 8%NiPO/T-CZS in a solution mainly composed of polylactic acid(PLA),which exhibits an in-crease by factors of 243.0 and 4.5 compared to NiPO and T-CZS individually.Meanwhile,PLA plastics are degraded into organic chemicals including formic acid,acetic acid,and pyruvic acid.Moreover,NiPO ex-hibits(localized surface plasmon resonance)LSPR effect,which can broaden the light absorption range of the system,reduce the H_(2)evolution overpotential,and enhance electron utilization efficiency.Based on electron capture experiments and band theory analysis,the introducing of plastic as an electron donor further accelerates the evolution process of H_(2),while alkaline sodium hydroxide(NaOH)solution pro-motes the PLA dissociation and enhances oxidation driving force,indirectly promoting the H_(2)evolution kinetics of this system.The present research offers prospective solutions for engineering solar-powered H_(2)evolution to tackle energy challenges.展开更多
The construction of crystalline/amorphous g-C_(3)N_(4)homojunctions presents a versatile strategy to obtain all-organic homojunction photocatalysts with better interface matching and lower interface charge carrier mov...The construction of crystalline/amorphous g-C_(3)N_(4)homojunctions presents a versatile strategy to obtain all-organic homojunction photocatalysts with better interface matching and lower interface charge carrier movement resistance for optimized photocatalytic activity.However,the process entails a complex multi-step workup,which compromises its feasibility.To overcome this challenge,this work provided an innovative Na_(2)CO_(3)-induced crystallinity modulation strategy to construct a Na-doped crystalline/amorphous g-C_(3)N_(4)S-scheme homojunction photocatalyst in a single step.The approach involves the initial pre-assembling of melamine and cyanuric acid molecules,and subsequent introduction of Na_(2)CO_(3)before the calcination.Na_(2)CO_(3)plays key roles to induce in-situ crystallinity modulation during the calcination and as a source for Na-doping.The prepared g-C_(3)N_(4)S-scheme homojunction photocatalyst demonstrated a prominent H_(2)O_(2)-production rate of 444.6μmol·L^(-1)·h^(-1),which is 6.1-fold higher than that of bulk g-C_(3)N_(4).The enhanced activity was attributed to the synergistic effect of charge carrier separation induced by the S-scheme homojunction system,and the optimized interfacial H_(2)O_(2)generation kinetics.The latter was fostered by the Na-doping.This study provides an innovative approach for the one-step construction of g-C_(3)N_(4)S-scheme homojunction and its integration in photocatalytic applications.展开更多
A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acid...A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.展开更多
基金supported by the National Natural Science Foun-dation of China(No.62004143)the Key R&D Program of Hubei Province(No.2022BAA084)the Natural Science Foundation of Hubei Province(No.2021CFB133).
文摘Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3)N_(4)(N,S-g-C_(3)N_(4))is elaborately designed on the basis of theoretical predictions of first-principle density functional theory(DFT).The calculated Gibbs free energy of adsorbed hydrogen(ΔGH∗)for N,S-g-C_(3)N_(4) at the N-doping active sites is extremely close to zero(0.01 eV).Inspired by the theoretical predictions,the N,S-g-C_(3)N_(4) is successfully fabricated through ammonia-rich pyrolysis synthesis strategy,in which ammonia is in-situ obtained by pyrolyzing melamine.Subsequent characterizations indicate that the N,S-g-C_(3)N_(4) possesses high specific surface area,outstanding light utilization,good hydrophilicity,and efficient carrier transfer efficiency.Consequently,the N,S-g-C_(3)N_(4) displays an extremely high H2 evolution rate of 8269.9μmol g−1 h−1,achieves an apparent quantum efficiency(AQE)of 3.24%,and also possesses outsatnding durability.Theoretical calculations further demonstrate that N and S dopants can not only introduce doping energy level to reduce the band gap,but also induce charge redistribution to facilitate hydrogen adsorption,thus promoting the photocatalytic HER process.Moreover,femtosecond transient absorption(fs-TA)spectroscopy further corroborates the efficient photogenerated carrier transport of N,S-g-C_(3)N_(4).This research highlights a promising and reliable strategy to achieve superior photocatalytic activity,and exhibits significant guidance for precise designing high-efficiency photocatalysts.
基金financially supported by The Local Science and Development Fund Project Guided by the Central Govern-ment(No.24ZYQM001)the National Natural Science Foundation of China(Nos.22378326,11974276,and22078261)+6 种基金the Natural Science Basic Research Program of Shaanxi Province(No.2023-JC-YB-115)the Shaanxi Key Science and Technology Innovation Team Project(No.2022TD-33)the Qin Chuangyuan project of Shaanxi Province(No.QCYRCXM2022-213)the Basic Science Re-search Program of Shaanxi Basic Sciences Institute(Chemistry,Bi-ology,No.23JHQ081)the Key Research and Development Program of Shaanxi Province(No.2024GX-YBXM-449)the Initial Scientific Research Fund of Northwest University(S.Tao),Excellent Doctoral Dissertation Cultivation Program at Northwestern University(No.YB2024012)the Program of China Scholarship Council(No.202406970056)。
文摘The development of catalysts that can efficiently separate both bulk and interface charges is crucial for conversion and utilization of solar energy.In this study,a homo-heterojunction was fabricated by combin-ing twinned-Cd_(0.5)Zn_(0.5)S(T-CZS)and Ni_(3)(PO_(4))_(2)with crystalline water(NiPO)using a solvent evaporation strategy for efficient photocatalytic H_(2)evolution in water containing degradable plastics.The bulk phase of T-CZS consists of wurtzite Cd_(0.5)Zn_(0.5)S(WZ-CZS)and zinc blende Cd_(0.5)Zn_(0.5)S(ZB-CZS),they exhibit a slight difference in energy range and can form S-scheme homojunction,while NiPO and T-CZS constitute the S-scheme heterojunction,they work together to promote the separation of bulk and interface charges.This double S-scheme homo-heterojunction achieves a hydrogen evolution rate(rH_(2))of 73.2 mmol h−1 g−1 over 8%NiPO/T-CZS in a solution mainly composed of polylactic acid(PLA),which exhibits an in-crease by factors of 243.0 and 4.5 compared to NiPO and T-CZS individually.Meanwhile,PLA plastics are degraded into organic chemicals including formic acid,acetic acid,and pyruvic acid.Moreover,NiPO ex-hibits(localized surface plasmon resonance)LSPR effect,which can broaden the light absorption range of the system,reduce the H_(2)evolution overpotential,and enhance electron utilization efficiency.Based on electron capture experiments and band theory analysis,the introducing of plastic as an electron donor further accelerates the evolution process of H_(2),while alkaline sodium hydroxide(NaOH)solution pro-motes the PLA dissociation and enhances oxidation driving force,indirectly promoting the H_(2)evolution kinetics of this system.The present research offers prospective solutions for engineering solar-powered H_(2)evolution to tackle energy challenges.
文摘The construction of crystalline/amorphous g-C_(3)N_(4)homojunctions presents a versatile strategy to obtain all-organic homojunction photocatalysts with better interface matching and lower interface charge carrier movement resistance for optimized photocatalytic activity.However,the process entails a complex multi-step workup,which compromises its feasibility.To overcome this challenge,this work provided an innovative Na_(2)CO_(3)-induced crystallinity modulation strategy to construct a Na-doped crystalline/amorphous g-C_(3)N_(4)S-scheme homojunction photocatalyst in a single step.The approach involves the initial pre-assembling of melamine and cyanuric acid molecules,and subsequent introduction of Na_(2)CO_(3)before the calcination.Na_(2)CO_(3)plays key roles to induce in-situ crystallinity modulation during the calcination and as a source for Na-doping.The prepared g-C_(3)N_(4)S-scheme homojunction photocatalyst demonstrated a prominent H_(2)O_(2)-production rate of 444.6μmol·L^(-1)·h^(-1),which is 6.1-fold higher than that of bulk g-C_(3)N_(4).The enhanced activity was attributed to the synergistic effect of charge carrier separation induced by the S-scheme homojunction system,and the optimized interfacial H_(2)O_(2)generation kinetics.The latter was fostered by the Na-doping.This study provides an innovative approach for the one-step construction of g-C_(3)N_(4)S-scheme homojunction and its integration in photocatalytic applications.
文摘A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.
