MOF-templated tubular Ni_(1−x)Co_(x)S_(2)-CdS heterojunction with intensified direct Z-scheme charge transmission for highly promoted visible-light photocatalysis

Hollow semiconductor nanostructures with direct Z-scheme heterojunction have significant advantages for photocatalytic reactions,and optimizing the interfacial charge transmission of Z-scheme heterojunction is the hinge to achieve excellent solar conversion efficiency.In this work,tubular Ni_(1−x)Co_(x)S_(2)-CdS heterostructures with reinforced Z-scheme charge transmission were constructed through an In-metal-organic framework(MOF)templated strategy.The Z-scheme charge transfer mechanism was sufficiently confirmed by combining density functional theory(DFT)calculation,X-ray photoelectron spectroscopy(XPS),surface photovoltage spectroscopy(SPV),and radical testing results.Crucially,the use of sodium citrate complexant contributes to the formation of intimate heterointerface,and the Fermi level gap between CdS and NiS_(2)is enlarged through Co doping into NiS_(2),which enhances the built-in electric field and photo-carriers transmission driving force for Ni_(1−x)Co_(x)S_(2)-CdS heterojunction,resulting in an evidently promoted activity toward H2 evolution reaction(HER).Under visible-light(λ>400 nm)irradiation,the Ni_(1−x)Co_(x)S_(2)-CdS composite with 10 mol%Co doping and 80 wt.%CdS(NC_(0.10)S-80%CdS)achieved an outstanding HER rate up to 35.94 mmol·g^(−1)·h^(−1)(corresponding to the apparent quantum efficiency of 34.7%at 420 nm),approximately 76.4 times that of 3 wt.%Pt-loaded CdS and it is much superior to that of most CdS-based photocatalysts ever reported.Moreover,the good photocatalytic durability of Ni_(1−x)Co_(x)S_(2)-CdS heterostructures was validated by cycling and long-term HER tests.This work could inspire the development of high-performance Z-scheme heterojunction via optimizing the morphology and interfacial charge transmission.

Transmission Use of System Charging for Differentiating Long-term Impacts from Various Generation Technologies

This paper proposes a novel transmission use of system(TUoS)charging method,which is able to 1)acknowledge the trade-offs between short-run congestion cost and long-run investment cost when justifying economic network investment,2)identify the impacts of different generation technologies on congestion cost and network investment,and 3)translate these impacts into economically efficient TUoS tariffs that differentiate generation technologies.An incremental capacity change from a generator will impact the congestion costs at each branch,which is then translated into the impacts on investment time horizons.The difference in the present values with and without the incremental change for a branch is its long-run incremental cost(LRIC).The final TUoS tariff for this generator is the sum of all LRIC triggered by its capacity increment.The proposed method is demonstrated on a modified IEEE 14-bus system to show its effectiveness over the traditional approach.Results show that it can provide cost-reflective TUoS tariffs for different generation technologies at the same sites by examining their respective impacts on congestion and investment.It thus can incentivize appropriate generation expansion to reduce congestion costs and ultimately network investment cost.