Multi-objective global optimization approach predicted quasi-layered ternary TiOS crystals with promising photocatalytic properties

Titanium dioxide(TiO_(2))has attracted considerable research attentions for its promising applications in solar cells and photocatalytic devices.However,the intrinsic challenge lies in the relatively low energy conversion efficiency of TiO_(2),primarily attributed to the substantial band gaps(exceeding 3.0 eV)associated with its rutile and anatase phases.Leveraging multi-objective global optimization,we have identified two quasi-layered ternary Ti-O-S crystals,composed of titanium,oxygen,and sulfur.The calculations of formation energy,phonon dispersions,and thermal stability confirm the chemical,dynamical and thermal stability of these newly discovered phases.Employing the state-of-art hybrid density functional approach and many-body perturbation theory(quasiparticle GW approach and Bethe-Salpeter equation),we calculate the optical properties of both the TiOS phases.Significantly,both phases show favorable photocatalytic characteristics,featuring band gaps suitable for visible optical absorption and appropriate band alignments with water for effective charge carrier separation.Therefore,ternary compound TiOS holds the potential for achieving high-efficiency photochemical conversion,showing our multi-objective global optimization provides a new approach for novel environmental and energy materials design with multicomponent compounds.

C9N4 as excellent dual electrocatalyst:A first principles study

We perform first principles calculations to investigate the catalytic behavior of C_(9)N_(4)nanosheet for water splitting.For the pristine C_(9)N_(4),we find that,at different hydrogen coverages,two H atoms adsorbed on the 12-membered ring and one H atom adsorbed on the 9-membered ring show excellent performance of hydrogen evolution reaction(HER).Tensile strain could improve the catalytic ability of C_(9)N_(4)and strain can be practically introduced by building C_(9)N_(4)/BiN,and C_(9)N_(4)/GaAs heterojunctions.We demonstrate that the HER performance of heterojunctions is indeed improved compared with that of C_(9)N_(4)nanosheet.Anchoring transition metal atoms on C_(9)N_(4)is another strategy to apply strain.It shows that Rh@C_(9)N_(4)exhibits superior HER property with very low Gibbs free energy change of-30 meV.Under tensile strain within~2%,Rh@C_(9)N_(4)could catalyze HER readily.Moreover,the catalyst Rh@C_(9)N_(4)works well for oxygen evolution reaction(OER)with an overpotential of 0.58 V.Our results suggest that Rh@C_(9)N_(4)is favorable for both HER and OER because of its metallic conductivity,close-zero Gibbs free energy change,and low oneset overpotential.The outstanding performance of C_(9)N_(4)nanosheet could be attributed to the tunable porous structure and electronic structure compatibility.

Optomechanical state transfer between two distant membranes in the presence of non-Markovian environments

The quantum state transfer between two membranes in coupled cavities is studied when the system is surrounded by non-Markovian environments. An analytical approach for describing non-Markovian memory effects that impact on the state transfer between distant membranes is presented. We show that quantum state transfer can be implemented with high efficiency by utilizing the experimental spectral density, and the performance of state transfer in non-Markovian environments is much better than that in Markovian environments, especially when the tunneling strength between the two cavities is not very large.

Two-dimensional PC_(3) as a promising anode material for potassium-ion batteries:First-principles calculations

With the diversified development of the battery industry,potassium-ion batteries(PIBs)have aroused widespread interest due to their safety and high potassium reserves on earth.However,the lack of suitable anode materials limits their development and application to a certain extent.Based on first-principles calculations,we investigate the possibility of using PC_(3) monolayer as the anode material for PIBs.PC_(3)sheet has excellent electrical properties and meets the prerequisite of anode materials.The storage capacity of potassium is as high as 1200 mAh·g^(-1),which is better than many other reported potassium-ion anode materials.In addition,the outstanding advantages of PC_(3)sheet,such as low diffusion barrier and moderate open-circuit voltage,make it a potential anode candidate for PIBs.