Challenges associated with the cathode material of Lithium–oxygen (Li–O 2 ) battery, particularly the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction, as well as the accumulation of discharge product Li 2 O 2 , have hindered its further advancement. Here, an in-situ synthesis strategy was adopted to load a bimetallic Ni–Co metal–organic framework (Ni/Co-MOF) onto MXene (Ti 3 C 2 ) layers. Subsequently, a free-standing and flexible Ni/Co-MOF@Ti 3 C 2 hybrid membrane is prepared via a layer-by-layer self-assembly method, specifically designed for efficient ORR and as a cathode for Li–O 2 batteries. The Ni/Co-MOF@Ti 3 C 2 hybrid membrane integrates the high conductivity, unique two-dimensional layered structure, and excellent mechanical properties of Ti 3 C 2 with the bimetallic active sites of Ni/Co-MOF, exhibiting remarkable ORR catalytic activity in an O 2 -saturated 1 M LiTFSI electrolyte. The structural characteristics of the hybrid membrane provide smoother expansion pathways for Li + and O 2 , effectively promoting the deposition and decomposition of Li 2 O 2 . This not only enhances the electrochemical performance of the Li–O 2 battery but also overcomes the inherent limitations of traditional slurry-based cathode preparation methods. Experimental results demonstrate that Li–O 2 batteries utilizing the Ni/Co-MOF@Ti 3 C 2 hybrid membrane as the cathode achieve an ultra-high capacity of 36,125 mAh/g at a current density of 1000 mA/g, while exhibiting excellent cycle stability (271 cycles with a limited capacity of 1000 mAh/g at 1000 mA/g) and outstanding rate performance. The hybrid membrane’s capacity and cycle performance can be further optimized by controlling its thickness. These promising results offer novel insights into the innovative design of air cathodes for metal–air batteries, and the proposed method provides a new route for the manufacture of high-performance battery cathodes.
Plasma-assisted ammonia synthesis (PAAS) can produce ammonia using highly energetic, electronically excited nitrogen and Hydrogen radicals at low temperatures and atmospheric pressure, which has been regarded as a prospective alternative to the Haber − Bosch process. PAAS can exclusively use renewable power (solar, wind, etc.) to achieve green, decentralized and efficient ammonia synthesis. However, current catalysts for PAAS are suffering from low efficiency, poor stability and cyclability. Herein, we demonstrate a one-step hydrothermal synthesis of Ni-Co bimetallic metal–organic frameworks (MOFs) for PAAS. Attributed to the amplified gas transport capability and bimetallic coupling, the Ni-Co-MOF exhibits significantly improved PAAS performance: 88.21 μmol g −1 ·min −1 , above 30 % increase over 5 wt% Ni/Al 2 O 3 . The high stability of Ni-Co-MOF under the harsh electric field enables its durable performance (36 h) and excellent cyclability (24 cycles). Finally, to determine the viability of PAAS for industrial applications, we construct a hypothetical zero-carbon ammonia plant using only renewable energy sources, and the outcomes indicate that PAAS has significant competitiveness for future ammonia production.
Zhihao Xu,Qinzhi Wang,Hui Zhangsun,Shuang Zhao,Yijian Zhao,Li Wang
In this work, we propose a electrochemical enzyme-free glucose sensor by direct growth of conductive Ni/Co bimetal MOF on carbon cloth [Ni/Co(HHTP)MOF/CC] via a facile hydrothermal method. Due to excellent conductivity between Ni/Co(HHTP)MOF and CC, synergic catalytic effect of Ni and Co elements, the Ni/Co(HHTP)MOF/CC not only provides larger surface area and more effective active sites, but also boosts the charge transports and electro-catalytic performance. Under optimized conditions, the Ni/Co(HHTP)MOF/CC shows excellent activity with a linear range of 0.3 μM–2.312 mM, a low detection limit of 100 nM (S/N = 3), a fast response time of 2 s and a high sensitivity of 3250 μA mM −1 cm −2 . Furthermore, the Ni/Co(HHTP)MOF/CC was successfully applied for the detection of glucose in real serum and beverages with competitive performances. This facile and cost-effective method provides a novel strategy for monitoring of glucose in biological and food samples.
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