Photocatalysis offers a sustainable solution to two pressing global issues:greenhouse gas mitigation and clean energy generation.By harnessing light energy,photocatalytic processes enable water splitting for hydrogen ...Photocatalysis offers a sustainable solution to two pressing global issues:greenhouse gas mitigation and clean energy generation.By harnessing light energy,photocatalytic processes enable water splitting for hydrogen production and CO_(2) conversion into value-added products.Among the materials explored for photocatalysis,nickel-based photocatalysts have emerged as highly promising due to their low cost,abundance,stability,and efficiency.This review summarizes recent advancements in Ni-based photocatalysts,highlighting their role in improving photocatalytic performance by enhancing light absorption,charge separation,and reducing charge recombination.Key challenges and future directions for optimizing these materials are also discussed,offering insights into their potential for advancing clean energy technologies.展开更多
Since the past few years,Pu(V)has gained much attention due to its potential contribution to the environmental migration of actinides.However,the preparation of concentrated(up to mM)and pure Pu(V)solutions is quite d...Since the past few years,Pu(V)has gained much attention due to its potential contribution to the environmental migration of actinides.However,the preparation of concentrated(up to mM)and pure Pu(V)solutions is quite difficult and often hindered by its great instability towards disproportionation,thus limiting the accessibility to physical and chemical property data.This work describes the rapid and facile sonochemical preparation of relatively stable Pu(V)solutions in the millimolar range free from the admixtures of the other oxidation states of plutonium.The mechanism deals with the sonochemical reduction of Pu(VI)in weakly acidic perchloric solutions by using the in situ generated H_(2)O_(2),where the kinetics can be dramatically enhanced under high frequency ultrasound and an Ar/O_(2) atmosphere.The quasi-exclusive presence of the Pu(V)aqua ion in solution was evidenced by UV-vis absorption spectroscopy.The prepared solutions were found to be stable for more than one month which allowed the accurate XAFS and NMR investigations of Pu(V).EXAFS spectra revealed the presence of two trans dioxo PuvO bonds at 1.81Åand 4-6 equatorial Pu-Oeq interactions at 2.47Åcharacteristic of coordinated water molecules.The exact number of water molecules(N[Oeq(H_(2)O)]=4)was determined by simulating the EXAFS spectra of the PuO_(2)+aqua complexes using DFT calculations(geometry and the Debye-Waller factor)and comparing them with experimental signals.For the first time,the magnetic susceptibility of the pentavalent state of plutonium in aqueous solutions was also determined(χM=16.3×10^(-9) m^(3) mol^(-1) at 25℃)and the related Curie constant was estimated(C=6.896×10^(-6 )m^(3) K mol^(-1)).展开更多
文摘Photocatalysis offers a sustainable solution to two pressing global issues:greenhouse gas mitigation and clean energy generation.By harnessing light energy,photocatalytic processes enable water splitting for hydrogen production and CO_(2) conversion into value-added products.Among the materials explored for photocatalysis,nickel-based photocatalysts have emerged as highly promising due to their low cost,abundance,stability,and efficiency.This review summarizes recent advancements in Ni-based photocatalysts,highlighting their role in improving photocatalytic performance by enhancing light absorption,charge separation,and reducing charge recombination.Key challenges and future directions for optimizing these materials are also discussed,offering insights into their potential for advancing clean energy technologies.
文摘Since the past few years,Pu(V)has gained much attention due to its potential contribution to the environmental migration of actinides.However,the preparation of concentrated(up to mM)and pure Pu(V)solutions is quite difficult and often hindered by its great instability towards disproportionation,thus limiting the accessibility to physical and chemical property data.This work describes the rapid and facile sonochemical preparation of relatively stable Pu(V)solutions in the millimolar range free from the admixtures of the other oxidation states of plutonium.The mechanism deals with the sonochemical reduction of Pu(VI)in weakly acidic perchloric solutions by using the in situ generated H_(2)O_(2),where the kinetics can be dramatically enhanced under high frequency ultrasound and an Ar/O_(2) atmosphere.The quasi-exclusive presence of the Pu(V)aqua ion in solution was evidenced by UV-vis absorption spectroscopy.The prepared solutions were found to be stable for more than one month which allowed the accurate XAFS and NMR investigations of Pu(V).EXAFS spectra revealed the presence of two trans dioxo PuvO bonds at 1.81Åand 4-6 equatorial Pu-Oeq interactions at 2.47Åcharacteristic of coordinated water molecules.The exact number of water molecules(N[Oeq(H_(2)O)]=4)was determined by simulating the EXAFS spectra of the PuO_(2)+aqua complexes using DFT calculations(geometry and the Debye-Waller factor)and comparing them with experimental signals.For the first time,the magnetic susceptibility of the pentavalent state of plutonium in aqueous solutions was also determined(χM=16.3×10^(-9) m^(3) mol^(-1) at 25℃)and the related Curie constant was estimated(C=6.896×10^(-6 )m^(3) K mol^(-1)).
