s a promising alternative to sluggish Li2CO3-based Li-CO2 electrochemistry, Li2C2O4 offers a favorable 2e− discharge pathway, yet its selective formation and reversible decomposition remain debated. Herein, we propose a nonmetal-metal synergistic catalyst—B-Ti coregulated layered transition metal boride Ti18B18O9/graphene (B-Ti/TiBOG)—to enable efficient CO2-to-Li2C2O4 conversion via frontier orbital engineering (FOE). Density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations reveal that the low electronegativity of B (O > N > C > B) induces asymmetric Ti coordination, driving strong B 2p and Ti 3d orbital hybridization near the Fermi level, and better structural stability, outperforming C/N/O-Ti analogs. Interestingly, this unique FO alignment activates CO2 by populating its antibonding orbitals through a bidirectional “acceptance-feedback” mechanism to enhance CO2 adsorption (from −0.19 to −1.05 eV). The B-Ti synergy selectively stabilizes Li2C2O4 nucleation while kinetically suppressing its conversion to Li2CO3 (barrier > 0.68 eV). Consequently, the hybrid B-Ti/TiBOG catalyst achieves exceptional bifunctionality, yielding a minimal total overpotential (0.75 V) for CO2-to-Li2C2O4 cycling—maintained in the tetraethylene glycol dimethyl ether (TEGDME) solvent environments. This work highlights electronegativity-driven FOE in B-Ti diatomic synergy as key for rechargeable Li-CO2 batteries.

Cortisol is a critical stress hormone.Its dysregulation is closely linked to various pathologies.Accurate and convenient monitoring of cortisol in biological fluids,like sweat and saliva,is essential for diagnostics and health management.Although conventional liquid chromatography tandem mass spectrometry offers high accuracy,it requires sophisticated instrumentation and specialized expertise.These factors restrict its use in point-of-care testing and wearable monitoring.In contrast,electrochemical sensor technology has emerged as a promising alternative.It allows for non-invasive,real-time,and dynamic cortisol monitoring due to easy fabrication,rapid response,miniaturization,and low cost.This method relies on recognition elements designed to bind trace cortisol molecules in complex biofluids.This review systematically summarizes recent advances in electrochemical sensors for cortisol determination,focusing on recognition elements such as antibodies(Abs),aptamers(Apts),and molecularly imprinted polymers(MIPs).It highlights innovative strategies and performance of recognition elements to improve specificity,anti-interference ability,and stability of the sensor.The review also discusses existing challenges and future trends,including developing novel recognition materials,integrating multiple functions,and combining sensing with artificial intelligence.It finally envisions the significant potential of electrochemical cortisol sensors based on various recognition elements for portable and wearable monitoring devices.

The cathode plate made of Ti has gradually become the main cathode of high-purity gold electrolysis because of the advantages of being lightweight,easy to peel off with the electrolysis Au,reusable,and low cost.So,it is necessary to investigate the electrodeposition mechanism for Au on Ti cathode.The electrodeposition process and mechanism of Au on Ti cathode were investigated in NaCl-HAuCl₄aqueous solution.Cyclic voltammetry(CV)was used to examine the reduction process and kinetics of[AuCl₄]on Ti electrode,and the transfer coefficients and diffusion coefficients of[AuCl₄]-on the surface of Ti electrode were calculated.Chronoamperometry(CA)was used to examine the nucleation mechanism of Au on Ti electrode surface.The three-electrode system was used for all electrochemical experiments.Ti electrode of 3 mm diameter was used as the working electrode,Pt sheet electrode(2 cm×2 cm)was used as the auxiliary electrode,and a saturated calomel electrode(SCE)was used as the reference electrode.The temperature of the electrolytic cell was maintained at 25℃during the experiment.To examine the electrochemical behavior of Au deposition on Ti electrode,CV tests were carried out in 0.1 mol·L^-1NaCl+5 mmol·L^-1HAuCl₄aqueous solution with a potential scanning range of^-1.5~1.5 V and a potential scanning rate of 50 mV·s^-1.Furthermore,the control tests were performed in 0.1 mol·L^-1NaCl and 0.1 mol·L^-1NaCl+5 mmol·L^-1HCl aqueous solutions with the same conditions in order to discuss the effects of NaCl and H+on CV curves of NaCl-HAuCl₄aqueous solution,respectively.The results of the control experiments showed that there was no reduction wave on CV curves in NaCl aqueous solution,while a reduction wave occurs on CV curves obtained in NaCl-HCl aqueous solution at^-1.3V,which was attributed to hydrogen evolution on the surface of Ti electrode due to H+addition.This also demonstrated that hydrogen evolution would occur at Ti electrode in aqueous solution containing 5 mmol·L^-1H+in the potential range of^-1.5~1.5 V and lead to the corresponding reduction wave on CV curve.Two reduction waves appeared on CV curve in 0.1 mol·L^-1NaCl+5 mmol·L^-1HAuCl₄solution at-0.56 and-0.92 V,respectively.Moreover,the positive scanning curve intersected with the negative scanning curve at-0.37 V during the back-scanning,and the positive scanning current started to be greater than the negative scanning current,which proved that there was Au deposited on the surface of Ti electrode.As the sweepback potential continued to increase,a corresponding oxidation wave appeared on the sweepback curve,which was attributed to the oxidation of Au deposited.These results indicated that an Au deposition reaction and a hydrogen evolution reaction would occur at Ti electrode in NaCl-HAuCl₄aqueous solution in the potential interval of^-1.5~1.5 V.Consequently,the two reduction waves appearing on CV curve in NaCl-HAuCl₄aqueous solution corresponded to the reduction of[AuCl₄]-and H+,respectively.An additional CV test was performed in NaCl-HAuCl₄aqueous solution to investigate the deposition mechanism of Au on Ti electrode further.The endpoint potential in the negative direction of this scan was adjusted to-0.7 V,while the other conditions were kept constant.There was only one reduction wave and the corresponding oxidation wave on CV curve,which indicated that the deposition reaction of Au on Ti electrode occurred before-0.7 V,i.e.,the first reduction wave appearing on CV curve in NaCl-HAuCl₄aqueous solution corresponded to the deposition reaction of Au,the second reduction wave corresponded to the hydrogen evolution reaction,and the deposition of Au was a one-step reduction process of[AuCl₄]-→Au.CV tests were carried out to investigate the reduction kinetics of[AuCl₄]-on the surface of Ti electrode in 0.1 mol·L^-1NaCl+5 mmol·L^-1HAuCl₄aqueous solution at different scan rates.The reduction wave potential Ep at different scan rates was linearly related to lgv,and the value of Ep became more negative as the scan rate increased.Concurrently,the reduction wave current density jp was linearly related to v1/2.These results indicated that the deposition of Au was an irreversible process controlled by diffusion.The transfer and diffusion coefficients of[AuCl₄]-on Ti surface were calculated to be 0.157 and 1.16×10^-4cm²·s^-1,respectively,based on the data of CV curve obtained at different scan rates.Chronoamperometry tests were carried out at different potentials to investigate the nucleation mechanism of Au on Ti electrode.With the fall of the step potential,the time-current curves start to peak,and the current dropped rapidly after reaching the peak Im and eventually stabilized.This phenomenon indicated that the nucleation process of Au on Ti surface belonged to three-dimensional nucleation.Comparing the actual nucleation curves with the theoretical nucleation curves,it was determined that the nucleation of Au on Ti surface was three-dimensional and follows the Scharifer-Hills transient nucleation theory.

This study examines the feasibility of integrating advanced battery technologies into electrified propulsion systems for aviation as a pathway toward carbon emission reduction. While the successful deployment of battery-powered electric vehicles (EVs) has demonstrated the potential of electrification in sustainable mobility, the aviation sector presents distinct technical and operational challenges that require specialized engineering solutions. This work provides a comprehensive review of recent industrial developments and scholarly literature to evaluate the technological, environmental, and economic viability of electrified aircraft. Key performance limitations and energy density constraints associated with current lithium-based batteries are analyzed, along with their safety considerations and life cycle sustainability. In addition, the operational costs of battery-powered and hybrid-electric aircraft concepts are compared with those of conventional jet fuel-based systems. Recent progress in hybrid-electric propulsion architectures, emerging battery chemistries such as lithium-metal and lithium-sulfur, and future directions for propulsion system integration are also discussed. Overall, this study offers insights into sustainable aviation strategies and identifies critical research directions to accelerate the transition toward carbon-neutral flight.