Design of a Single-Atom In-N3-S site to Modulate Exciton Behavior in Carbon Nitride for Enhanced Photocatalytic Performance.

Rational tailoring of the local coordination environment of single atoms has demonstrated a significant impact on the electronic state and catalytic performance, but the development of catalysts beyond noble/transition metals is profoundly significant and highly desired. Herein, the main-group metal indium (In) single atom is immobilized on sulfur-doped porous carbon nitride nanosheets (In@CNS) in the form of three nitrogen atoms coordinated with one sulfur atom (In-N3-S). Both theoretical calculations and advanced characterization investigations clearly elucidated that the single-atomic In-N3-S structures on In@CNS are powerful in promoting the dissociation of excitons into more free carriers as well as the charge separation, synergistically elevating electron concentration by 2.19 times with respect to pristine CNS. Meanwhile, the loading of In single atoms on CNS is responsible for altering electronic structure and lowering the Gibbs free energy for hydrogen adsorption. Consequently, the optimized In@CNS-5.0 exhibited remarkable photocatalytic performance, remarkable water-splitting and tetracycline hydrochloride degradation. The H2 production achieved to 10.11 mmol h-1g-1 with a notable apparent quantum yield of 19.70% at 400 nm and remained at 10.40% at 420 nm. These findings open a new perspective for in-depth comprehending the effect of the main-group metal single-atom coordination environment on promoting photocatalytic performance.

Characterization of microresonator-geometry-deformation for cavity optomechanics.

We have studied the effect of geometry deformation on the mechanical frequencies and quality factors for different modes in the Whispering Gallery Mode (WGM) microresonators, that is unavoidable in the practical fabrication. The subsidence of the sphere and a more general condition with fewer symmetries and complex deformation of eccentricity, subsidence, and offset are first modeled in this paper, which could tune the mechanical frequency in a much wider spectral range than the pillar-diameter-induced perturbation. we also show that the mechanical quality factors for the non-whispering-gallery mechanical mode could be increased in the order of 4 magnitudes at a specific subsidence, and form a mechanical bound state in the continuum (BIC) which is induced by the symmetry breaking and reveals new mechanisms to confine radiation. A much broader BIC window width with higher mechanical quality factor could be achieved, which is of great importance in both fundamental research and scientific applications.

Arbitrary function resonance tuner of the optical microcavity with sub-MHz resolution.

Tuning the resonance frequency of an optical whispering gallery mode microcavity is extremely important in its various applications. Here we report the design and implementation of a function resonance tuner of an optical microcavity with a resolution of about 650 kHz (7 pm at 1450 nm band). A piezoelectric nano-positioner is used to mechanically compress the microsphere in its axial direction. Furthermore, the resonance can be periodically tuned as an arbitrary function, such as the sine and sigmoid functions, with over 99% fitting accuracy. This Letter greatly expands the application of ultrahigh quality factor microresonators in a multi-mode coupling system or time-floquet system.

Synthesis of Rice-Husk-Carbon-Supported Nickel Ferrite Catalyst for Reduction of Nitrophenols.

In this paper, magnetic NiFe2O4-RHC (rice husk carbon) catalysts with different NiFe2O4 contents are prepared through a one-step hydrothermal method and employed as a catalyst for the reduction of nitrophenols. The resulting catalysts are characterized using various techniques. It is indicated that the NiFe2O4 nanoparticles are well dispersed on the RHC with the average size of 9.97 nm and 224.13 m²·g-1 BET surface area. NiFe2O4-RHC (0.75) has the highest activity for the reduction of nitrophenols (k = 0°8872 min-1). The combination of NiFe2O4 nanoparticles with RHC results in a dramatic conversion of the inert NiFe2O4 into a highly active catalyst for the reduction of nitrophenols at 25 °C employing NaBH4 as the reducing agent in aqueous medium. The excellent catalytic performance of NiFe2O4-RHC (0.75) may be attributed to the specific characteristics of the nanostructure and the synergistic effect between NiFe2O4 and RHC. The effect of the substituent and temperature are also investigated. The activation energy was reduced to 15.342 kJ mol-1, facilitating the reaction at lower temperature. Furthermore, the catalyst NiFe2O4-RHC (0.75) is very cheap when RHC is introduced as the support compared to other carbon materials. The catalyst also exhibits magnetic performance and good stability; it can be used for 10 successive experiments with a conversion of 96%.

Circuit-Depth Reduction of Unitary-Coupled-Cluster Ansatz by Energy Sorting.

Quantum computation represents a revolutionary approach to solving problems in quantum chemistry. However, due to the limited quantum resources in the current noisy intermediate-scale quantum (NISQ) devices, quantum algorithms for large chemical systems remain a major task. In this work, we demonstrate that the circuit depth of the unitary coupled cluster (UCC) and UCC-based ansatzes in the algorithm of the variational quantum eigensolver can be significantly reduced by an energy-sorting strategy. Specifically, subsets of excitation operators are first prescreened from the operator pool according to its contribution to the total energy. The quantum circuit ansatz is then iteratively constructed until convergence of the final energy to a typical accuracy. For demonstration, this method has been successfully applied to molecular and periodic systems. Particularly, a reduction of 50%-98% in the number of operators is observed while retaining the accuracy of the original UCCSD operator pools. This method can be straightforwardly extended to general parametric variational ansatzes.

Ternary Transition Metal Sulfide as High Real Energy Cathode for Lithium-Sulfur Pouch Cell Under Lean Electrolyte Conditions.

Fabrication of a highly porous sulfur host and using excess electrolyte is a common strategy to enhance sulfur utilization. However, flooded electrolyte limits the practical energy density of Li-S pouch cells. In this study, a novel Fe0.34 Co0.33 Ni0.33 S2 (FCN) is proposed as host for sulfur to realize Ah-level Li-S full cells demonstrating excellent electrochemical performances under 2 µL mg-1 lean electrolyte conditions. Moreover, Kelvin probe force microscopy shows that the FCN surface contains positive charge with a potential of ≈70 mV, improving the binding of polysulfides through Lewis acid base interaction. In particular, the FCN@S possesses inherent electrochemical activity of simultaneous anionic and cationic redox for lithium storage in the voltage window of 1.8-2.1 V, which additionally contributes to the specific capacity. Due to the low carbon content (≈10 wt%), the sulfur loading is as high as ≈6 mg cm-2 , approaching an outstanding energy density of 394.9 and 267.2 Wh kg-1 at the current density of 1.5 and 4 mA cm-2 , respectively. Moreover, after 60 cycles at 1.5 mA cm-2 , the pouch cell still retains an energy of 300.2 Wh kg-1 . This study represents a milestone in the practical applications of high-energy Li-S batteries.

Synthesis and effects of new caffeic acid derivatives on nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages.

In this study, 20 new derivatives of caffeic acid esters were synthesized and their inhibitory activities against the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages were determined. Compounds 3l, 3r, 3s and 3t were found to decrease nitrite levels in a dose-dependent manner in LPS-induced cells and showed potent inhibitory activities against the NO production in RAW264.7 macrophages with IC50 values of 7.4, 5.9, 3.3 and 2.2 µM, respectively. They could be selected as compromising compounds for the later pharmacological study.