Counterbalancing of electron and hole transfer in quantum dots for enhanced photocatalytic H_(2)evolution

In-depth understandings of charge carrier transfer dynamics in any artificial catalytic system are of critical importance for the future design of highly efficient photocatalysts.Herein,we synthesized sub-monolayer ZnSe partial-shell coated CdSe/CdS core/shell quantum dots in a controlled fashion.The ZnSe decorated quantum dots were employed as a model catalyst for photogeneration of H_(2)under light illumination.Both theoretical calculations and experimental results unravel that the growth of ZnSe partial-shell would retard the photogenerated electron transfer,and meanwhile,accelerate the corresponding hole migration process during the H_(2)photogeneration reaction in the artificial photocatalytic system.As such,the performance of the relevant photocatalytic system can be modulated and optimized,and accordingly,a plausible underlying mechanism is rationalized.

Performance and Mechanism Research of Au-HSTiO2 on Photocatalytic Hydrogen Production

In this paper,we report our attempts to raise the efficiency of liquid reduction method when using high specific surface area TiO2(HSTiO2)by doping Au.Characterization of Au-HSTiO2 was conducted via XRD,UV-vis,SEM,and photocurrent intensity.The experimental results show that Au-HSTiO2 exhibits prominently higher photocatalytic hydrogen production than TiO2 and HSTiO2.Enhanced photosynthetic hydrogen production ability of Au-HSTiO2 should be attributed to the presence of abundant surface active sites of HSTiO2,remarkably extending electronic holes in Au doping.This study provides a promising photosynthetic material for hydrogen production.

Porous current collector enables carbon superior electrochemical performance for K-ion capacitors

The current collector is an indispensable component in potassium-ion hybrid capacitors,which not only provides mechanical support to load electrode materials,but also collects and outputs the current generated.Herein,we investigate the effect of three different current collectors on the electrochemical properties of potassium ion capacitors using carbon black anode as a demonstration.Because of better adhesion and lower charge transfer resistance,the specific capacity of half-cells assembled using three-dimensional(3D)porous copper foil(PCu)and copper as current collector is better than that of Al foil,which stabilizes at 138.2 and 132.8 mAh·g^(-1)after 100 cycles at 0.05 A·g^(-1).The potassium-ion capacitor assembled using PCu exhibits an excellent energy/power density of 86.1 Wh·kg^(-1)and 4000 W·kg^(-1),respectively.This work will boost the rational design and provide an effective strategy to improve the performance of potassium-ion capacitors.

Defective TiO_(2)hollow nanospheres as photo-electrocatalysts for photo-assisted Li-O_(2)batteries

The large overpotential for conventional Li-O_(2) batteries is an enormous challenge,which impedes their practical application.Here,we prepare a defective TiO_(2)(Ov-TiO_(2)) hollow nanosphere as photoelectrocatalyst for photo-assisted Li-O_(2) batteries to reduce the overpotential.Under illumination,the oxygen vacancies as a charge separation center contribute to the separation of electrons and holes.The generated electrons could promote reducing O_(2) to Li_(2)O_(2) during oxygen reduction reaction(ORR)process,while the generated holes are beneficial to Li_(2)O_(2) decomposition during oxygen evolution reaction(OER)process.Additionally,the proper concentration of oxygen vacancies will decrease the recombination rate between electrons and holes.The photo-assisted Li-O_(2) batteries with Ov-TiO_(2)-650 exhibit advanced performances,such as the low overpotential(0.70 V),the fine rate capability,and the considerable reversibility accompanied with the formation/decomposition of Li_(2)O_(2).We expect that these results could open a new mind to design of highly efficient photo-electrocatalysts for photo-assisted Li-O_(2) battery.

B-doped SiO_(x) composite with three dimensional conductive network for high performance lithium-ion battery anode

Currently,the practical application of SiO_(x) still has a huge hindrance in the area of lithium ion battery,because it is unable to achieve an effective contact with surrounding conducting materials,resulting in failure to form lithium ion migration tunnels.In this work,we presented a facile method to synthesize the B-doped SiOx composite by adhering SiO_(x) particles with MWCNT(multi-walled carbon nanotube)under the assistance of lithium metaborate(LiBO_(2)).LiBO_(2),as a sintering aid,not only can react with SiO_(x) to form a compacted framework,but also build a three-dimensional(3D)conductive network for ions transportation.Furthermore,B-SiO_(x)@CNT@LBO anode delivers a remarkable lithium storage performance in terms of long cycles and high rate capability.A full cell coupled with NCM622 cathode achieves a high energy density of 429.5 Wh kg^(-1) based on the total mass of cathode.