Photocatalytic hydrogen generation from water-splitting holds huge promise for resolving the current energy shortage and environmental issues.Nevertheless,it is still challenging so far to develop non-noble-metal phot...Photocatalytic hydrogen generation from water-splitting holds huge promise for resolving the current energy shortage and environmental issues.Nevertheless,it is still challenging so far to develop non-noble-metal photocatalysts which are efficient toward solar-powered hydrogen evolution reaction(HER).In this work,through an ultrasonic water-bath strategy combined with solvothermal and electrostatic assembly processes,we obtain homogeneous Cd_(1-x)Zn_(x)S–Ni_(2)P–MoS_(2) hybrid nano-spheres consisting of Cd_(1-x)Zn_(x)S solid solutions decorated by Ni_(2)P and 1 T/2 H MoS_(2) cocatalysts,which demonstrate excellent activity and stability for visible-light-responsive(λ>420 nm)H_(2) production.Specifically,the Cd_(1-x)Zn_(x)S-Ni_(2)P-MoS_(2) nano-spheres with 2 wt%Ni_(2)P and 0.2 wt%MoS_(2)(CZ_(0.7)S–2 N–0.2 M)exhibit the optimal HER activity of 55.77 mmol·g^(-1)·h^(-1),about 47 and 32 times more than that of CZ_(0.7)S and Pt–CZ_(0.7)S,respectively.The outstanding HER performance of Cd_(1-x)Zn_(x)S–Ni_(2)P–MoS_(2) can be ascribed to the presence of abundant HER active sites in Ni2 P nanoparticles and 1 T/2 H MoS_(2) nanosheets as well as the effective transfer and separation of charge carriers.Moreover,the coupling sequence of cocatalysts in Cd_(1-x)Zn_(x)S–Ni_(2)P–MoS_(2) is found to be critical in the regulation of charge transfer pathways and thus the resultant photocatalytic efficiency.The results displayed here could facilitate the engineering of high-performance photocatalysts employing multi-component cocatalysts for sustainable solar-to-fuel conversion.展开更多
The current study aims to investigate the particular case of two zeros in a Majorana neutrino mass matrix based on A_(4) symmetry,where charged lepton mass matrix is diagonal.The texture is M_(ν)^(S7) with(μ,μ)and(...The current study aims to investigate the particular case of two zeros in a Majorana neutrino mass matrix based on A_(4) symmetry,where charged lepton mass matrix is diagonal.The texture is M_(ν)^(S7) with(μ,μ)and(τ,τ)vanishing element of the neutrino mass matrix.The texture M_(ν)^(S7) has magic and μ−τsymmetry,with a tribimaximal form of the mixing matrix,which leads to θ_(13)=0 that it is not consistent with experimental data and at first,does not seem to be allowed.Since θ_(13) a small mixing angle compared to others neutrino mixing angles justifies the use of perturbation theory.We propose that,θ_(13),and the Dirac phase δ,and two Majorana phases ρ and σ could be generated by using a complex symmetric perturbation mass matrix in the mass basis and find that δm^(2)≡m_(2)^(2)-m_(1)^(2)≠0affect to the atmospheric mixing angle.We show that only the predictions of the case I,with Δ<0 and Re(α)<0,are consistent with the experimental data.Furthermore,the allowed range of our parameter space and complex elements of perturbation mass matrix are found,which led to finding the allowed region of the neutrino masses,the Majorana phases,the effective neutrino mass for the neutrinoless double beta decay,the allowed deviation of θ_(23) from 45°,and to predict the normal neutrino mass hierarchy.The predicted region of<m_(νββ)> and θ_(23) are in line with the current experimental data which indicate the accuracy of our model and its results.The results of the case II,with Δ>0 and Re(α)>0,are ruled out.展开更多
Spent UO2 fuel will rapidly be altered to U6+ phases in nuclear waste repositories. Be-cause most uranyl phases are based on sheet or chain structures and usually contain several mo-lecular water groups, site-mixing, ...Spent UO2 fuel will rapidly be altered to U6+ phases in nuclear waste repositories. Be-cause most uranyl phases are based on sheet or chain structures and usually contain several mo-lecular water groups, site-mixing, vacancies, as well as disorder in the orientation of hydrogen bonds may occur. A systematic survey of the published crystallographic data for uranates, uranyl oxide hydrates, phosphates, silicates, carbonates, and sulfates demonstrates that site-mixing ap-parently occurs in the structures of at least 31 uranyl phases. Calculations of the ideal site-mixing entropy indicate that the residual contribution that arises from substitution and vacancies to the third-law entropies of some uranyl phases is large. A brief examination of the crystal chemistry of water molecules in uranyl phases suggests that considerable residual entropy may be caused by the disorder of hydrogen bonds associated with interstitial H2O groups. In the geochemical envi-ronment that expected to occur in the near-field of nuclear waste repositories, the existence of structure-configurational entropy may reduce the uranium concentration of several log units in so-lutions equilibrated with some uranyl phases. Therefore, compositional analysis and structural de-terminations must be made on the samples used in calorimetric measurements, and the calorimet-ric data must be combined with solubility data to evaluate the thermodynamic stability of the inter-ested phases.展开更多
基金supported by the Foundation of State Key Laboratory of Structural Chemistry(20190021)the National Natural Science Foundation of China(51802170,21801150,51772162)+1 种基金the Natural Science Foundation of Shandong Province(ZR2018BEM014,ZR2019JQ14,ZR2019MB001)the Taishan Scholar Project of Shandong Province。
文摘Photocatalytic hydrogen generation from water-splitting holds huge promise for resolving the current energy shortage and environmental issues.Nevertheless,it is still challenging so far to develop non-noble-metal photocatalysts which are efficient toward solar-powered hydrogen evolution reaction(HER).In this work,through an ultrasonic water-bath strategy combined with solvothermal and electrostatic assembly processes,we obtain homogeneous Cd_(1-x)Zn_(x)S–Ni_(2)P–MoS_(2) hybrid nano-spheres consisting of Cd_(1-x)Zn_(x)S solid solutions decorated by Ni_(2)P and 1 T/2 H MoS_(2) cocatalysts,which demonstrate excellent activity and stability for visible-light-responsive(λ>420 nm)H_(2) production.Specifically,the Cd_(1-x)Zn_(x)S-Ni_(2)P-MoS_(2) nano-spheres with 2 wt%Ni_(2)P and 0.2 wt%MoS_(2)(CZ_(0.7)S–2 N–0.2 M)exhibit the optimal HER activity of 55.77 mmol·g^(-1)·h^(-1),about 47 and 32 times more than that of CZ_(0.7)S and Pt–CZ_(0.7)S,respectively.The outstanding HER performance of Cd_(1-x)Zn_(x)S–Ni_(2)P–MoS_(2) can be ascribed to the presence of abundant HER active sites in Ni2 P nanoparticles and 1 T/2 H MoS_(2) nanosheets as well as the effective transfer and separation of charge carriers.Moreover,the coupling sequence of cocatalysts in Cd_(1-x)Zn_(x)S–Ni_(2)P–MoS_(2) is found to be critical in the regulation of charge transfer pathways and thus the resultant photocatalytic efficiency.The results displayed here could facilitate the engineering of high-performance photocatalysts employing multi-component cocatalysts for sustainable solar-to-fuel conversion.
文摘The current study aims to investigate the particular case of two zeros in a Majorana neutrino mass matrix based on A_(4) symmetry,where charged lepton mass matrix is diagonal.The texture is M_(ν)^(S7) with(μ,μ)and(τ,τ)vanishing element of the neutrino mass matrix.The texture M_(ν)^(S7) has magic and μ−τsymmetry,with a tribimaximal form of the mixing matrix,which leads to θ_(13)=0 that it is not consistent with experimental data and at first,does not seem to be allowed.Since θ_(13) a small mixing angle compared to others neutrino mixing angles justifies the use of perturbation theory.We propose that,θ_(13),and the Dirac phase δ,and two Majorana phases ρ and σ could be generated by using a complex symmetric perturbation mass matrix in the mass basis and find that δm^(2)≡m_(2)^(2)-m_(1)^(2)≠0affect to the atmospheric mixing angle.We show that only the predictions of the case I,with Δ<0 and Re(α)<0,are consistent with the experimental data.Furthermore,the allowed range of our parameter space and complex elements of perturbation mass matrix are found,which led to finding the allowed region of the neutrino masses,the Majorana phases,the effective neutrino mass for the neutrinoless double beta decay,the allowed deviation of θ_(23) from 45°,and to predict the normal neutrino mass hierarchy.The predicted region of<m_(νββ)> and θ_(23) are in line with the current experimental data which indicate the accuracy of our model and its results.The results of the case II,with Δ>0 and Re(α)>0,are ruled out.
基金This work was supported by the National Natural Science Foundation of China(Grant No.40072095)the DOE/EMSP grant of USA(DE-FG07-97ER-14816,RCE).
文摘Spent UO2 fuel will rapidly be altered to U6+ phases in nuclear waste repositories. Be-cause most uranyl phases are based on sheet or chain structures and usually contain several mo-lecular water groups, site-mixing, vacancies, as well as disorder in the orientation of hydrogen bonds may occur. A systematic survey of the published crystallographic data for uranates, uranyl oxide hydrates, phosphates, silicates, carbonates, and sulfates demonstrates that site-mixing ap-parently occurs in the structures of at least 31 uranyl phases. Calculations of the ideal site-mixing entropy indicate that the residual contribution that arises from substitution and vacancies to the third-law entropies of some uranyl phases is large. A brief examination of the crystal chemistry of water molecules in uranyl phases suggests that considerable residual entropy may be caused by the disorder of hydrogen bonds associated with interstitial H2O groups. In the geochemical envi-ronment that expected to occur in the near-field of nuclear waste repositories, the existence of structure-configurational entropy may reduce the uranium concentration of several log units in so-lutions equilibrated with some uranyl phases. Therefore, compositional analysis and structural de-terminations must be made on the samples used in calorimetric measurements, and the calorimet-ric data must be combined with solubility data to evaluate the thermodynamic stability of the inter-ested phases.
