Rational construction of CuFe_(2)O_(4)@C/Cd_(0.9)Zn_(0.1)S S-scheme heterojunction photocatalyst for extraordinary photothermal-assisted photocatalytic H_(2) evolution

Rational design of photocatalyst to maximize the use of sunlight is one of the issues to be solved in photocatalysis technology.In this study,the CuFe_(2)O_(4)@C/Cd_(0.9)Zn_(0.1)S(CFO@C/CZS)S-scheme photocatalyst with photothermal effect was synthesized by ultrasonic self-assembly combined with calcination.The dark CFO@C absorbed visible light and partly converted into heat to promote the hydrogen evolution reaction.The presence of heterojunctions inhibited the photogenerated electron-hole recombination.The graphite-carbon layer provided a stable channel for electron transfer,and the presence of magnetic CFO made recycle easier.Under the action of photothermal assistance and heterojunction,the hydrogen evolution rate of the optimal CFO@C/CZS was 80.79 mmol g^(-1) h^(-1),which was 2.55 times and 260.61 times of that of pure CZS and CFO@C,respectively.Notably,the composite samples also exhibit excellent stability and a wide range of environmental adaptability.Through experimental tests and first-principles simulation calculation methods,the plausible mechanism of photoactivity enhancement was proposed.This work provided a feasible strategy of photothermal assistance for the development of heterojunction photocatalysts with distinctive hydrogen evolution.

Valence modulated nickel oxynitride network as integrated bifunctional electrodes for enhanced energy storage

As promising electrode materials,transition metal oxides have attracted considerable attention owing to their excellent performance in electrochemical energy storage.However,their poor conductivity and fragile structure limit their practical application.In this study,a binder-free nickel oxide/oxynitride network(NiON WS)bifunctional electrodes with cation multivalent states that exhibit high energy storage performance were synthesized for the first time.The massive active sites,high specific surface areas,and multiple cation valence states of NiON WS were advantageous for electrochemical redox reaction during its application in supercapacitors(1283.5 mF cm^(-2))and lithium-ion batteries(1345.0 mA h g^(-1)).Particularly,the NiON WS based flexible asymmetric SCs exhibit excellent capacitance and energy densities.First-principle calculations were employed to study the mechanism of the electrochemical performance improvement of NiON WS.This study demonstrates the potential of transition metal oxides electrode with high capacity and activity for electrochemical energy storage and conversion.

One stone,three birds:up-conversion,photothermal and p-n heterojunction to boost BiOBr:Yb^(3+),Er^(3+)/Cu_(3)Mo_(2)O_(9) full spectrum photodegradation

Broadening spectral response range to realize the full spectrum photocatalysis is crucial to develop photocatalysts with satisfactory light-energy conversion ability.A full-spectrum driven p-n heterojunction photocatalytic system was rationally designed through introducing the Er^(3+)/Yb^(3+)co-doped BiOBr with up-conversion effect as the collector of near infrared light and photocatalysts substrate.Meanwhile,Cu_(3)Mo_(2)O_(9) with the photothermal effect as a heat source to accelerate the reaction at the surface through absorbing the near infrared light.The photocatalytic activity of BiOBr:Yb^(3+),Er^(3+)/Cu3Mo2O9 composite was markedly strengthened under visible and near infrared light irradiation,and the BiOBr:Yb^(3+),Er^(3+)/Cu_(3)Mo_(2)O_(9)-5 composite displayed the optimal photodegradation activities for 0.03372 min^(-1) and 0.058 h^(-1),being 2.3-folds and 2.4-folds than that of pure BiOBr:Yb^(3+),Er^(3+)under the visible and near infrared light,respectively.The position of doped ions(Yb^(3+)and Er^(3+))in BiOBr:Yb^(3+),Er^(3+)was determined from the X-ray absorption fine structure spectra.And the reasonable mechanism of p-n heterojunction was proposed base on the results of experimental and density functional theory calculation.This work provides a rational strategy for the design and development of full-spectrum heterojunction photocatalysts with the up-conversion and photothermal effects to increase the photocatalytic performance.