RESUMO
Next-generation communication systems demand the integration of sensing, communication, and power transfer (PT) capabilities, requiring high spectral efficiency, energy efficiency, and low cost while also necessitating robustness in high-speed scenarios. Integrated sensing and communication systems (ISACSs) exhibit the ability to simultaneously perform communication and sensing tasks using a single RF signal, while simultaneous wireless information and power transfer (SWIPT) systems can handle simultaneous information and energy transmission, and orthogonal time frequency space (OTFS) signals are adept at handling high Doppler scenarios. Combining the advantages of these three technologies, a novel cyclic prefix (CP) OTFS-based integrated simultaneous wireless sensing, communication, and power transfer system (ISWSCPTS) framework is proposed in this work. Within the ISWSCPTS, the CP-OTFS matched filter (MF)-based target detection and parameter estimation (MF-TDaPE) algorithm is proposed to endow the system with sensing capabilities. To enhance the system's sensing capability, a waveform design algorithm based on CP-OTFS ambiguity function shaping (AFS) is proposed, which is solved by an iterative method. Furthermore, to maximize the system's sensing performance under communication and PT quality of service (QoS) constraints, a semidefinite relaxation (SDR) beamforming design (SDR-BD) algorithm is proposed, which is solved using through the SDR technique. The simulation results demonstrate that the ISWSCPTS exhibits stronger parameter estimation performance in high-speed scenarios compared to orthogonal frequency division multiplexing (OFDM), the waveform designed by CP-OTFS AFS demonstrates superior interference resilience, and the beamforming designed by SDR-BD strikes a balance in the overall performance of the ISWSCPTS.
RESUMO
Combining molecular metal complexes into coordination polymers (CPs) is an effective strategy for developing photocatalysts for CO2 reduction; however, most such reported catalysts are noble metal-containing CPs. Herein, two novel Zr-containing bimetallic CPs, Co-Zr and Ni-Zr, were designed and successfully synthesized by connecting 2,2':6',2â³-terpyridine-based molecular earth-abundant metal (Co or Ni) complexes with ZrO8 nodes. Both CPs were applied as catalysts for CO2 photoreduction to selectively produce CO. The catalytic performance of Co-Zr is better than that of Ni-Zr with a yield of 3654 µmol (g of catalyst)-1 for CO in 6 h (TON = 18.2). The difference between these two catalysts was analyzed with respect to band structure and charge migration ability. This work provides an effective way to introduce molecular earth-abundant metal complexes into coordination polymers for the construction of efficient noble metal-free CO2 photocatalysts.
RESUMO
Nowadays, the clean production of bio-based products and fixation of carbon dioxide (CO2) are highly desirable. In this work, carbonated fatty acid methyl esters have been successfully prepared in 99% yield by cycloaddition of CO2 with bio-based epoxidized methyl soyates. This was accomplished with a simple and cheap catalyst system of polyethylene glycol 400 (PEG-400) and potassium iodide (KI) under solvent-free conditions. Experimental parameters such as the molar ratio of polyethylene glycol to metal halide, catalyst loading, reaction temperature, reaction time and CO2 pressure were systematically evaluated. The PEG-400 and KI co-catalysts (4 mol%) could significantly promote the cycloaddition of CO2 with internal epoxides (epoxidized methyl soyates) to produce carbonated fatty acid methyl esters. FT-IR and NMR analyses were used to confirm the product, and 99% yield of the five-membered cyclic carbonated methyl soyates was obtained at 120 °C with 3.0 MPa pressure of CO2 for 20 h. This method provides a cleaner approach for the production of bio-based products.
