Owing to their safety and low cost, magnesium ion batteries (MIBs) have attracted much attention in recent years. However, the sluggish diffusion dynamics of magnesium ions hampers the search for appropriate cathode materials with excellent electrochemical performance. Herein, we design and synthesize a novel flexible three-dimensional-networked composite of iron vanadate nanosheet arrays/carbon cloths (3D FeVO/CC) as a binder-free cathode for MIBs. Relative to bare FeVO nanosheets, the 3D binder-free electrode with designed architecture enables a full range of electrochemical potential, including a high specific capacity of 270 mA h g⁻¹ and an increased life span (over 5000 cycles). Such achievable high-density energy originates from the synergistic optimization of electron and ion kinetics, while the durability benefits from the robust structure that prevents degradation in cycling. The single-phase reaction mechanism of FeVO in the magnesium ion storage process is also explored by in-situ X-ray diffraction and Raman technologies. Moreover, a flexible MIB pouch cell (3D FeVO/CC|MgNaTi₃O₇) is assembled and exhibits practical application potential. This work verifies that 3D FeVO/CC is a potential candidate cathode material that can satisfy the requirements of high-performance MIBs. It also opens a new avenue to improve the electrochemical performance of cathode materials for MIBs.

The CuO–Bi₂O₃/MgAl₂O₄ catalyst was synthesized via one-pot synthesis and used to catalyze formaldehyde (HCHO) ethynylation. Coprecipitation using Cu²⁺, Bi³⁺, Mg²⁺, and Al³⁺ nitrates and NaOH generated Cu and Bi oxides and spinel MgAl₂O₄ phase. The catalyst precursor was calcined at 450 °C. The catalytic performance of CuO–Bi₂O₃/MgAl₂O₄ in the synthesis of 1,4-butynediol via HCHO ethynylation was investigated. The presence of a new spinel phase enhanced the acid–base properties on the catalyst surface and prevented the aggregation of CuO particles. These properties resulted in improved CuO dispersion during calcination and CuO particle growth suppression, affording smaller CuO crystals. The MgAl₂O₄ support facilitated the reduction of Cu²⁺ to Cu⁺ and formation of abundant active species during the reaction. The catalyst exhibited abundant weakly basic, fewer strongly basic, and least acidic sites, which facilitated the adsorption of HCHO and acetylene. The catalytic performance of CuO–Bi₂O₃/MgAl₂O₄ demonstrated 97 % conversion and 80 % selectivity after the online monitoring of the ethynylation reaction for 6 h. The leaching of Cu during the reaction, as analyzed by inductively coupled plasma spectroscopy, was extremely low. Moreover, conversion and selectivity did not substantially change after eight cycles. In addition, the catalyst exhibited superior activity and long-term stability in the ethynylation reaction.

A spherical CuO-Bi₂O₃-MgO/SiO₂ catalyst was prepared using the coprecipitation-gel method. The study investigated the influence of the MgO/SiO₂ ratio on the catalyst structure and the activity of the catalyst in the preparation of 1,4-butanediol from formaldehyde acetylenation. The activity and filtration performance of the catalyst were compared with commercial samples. The study found that different MgO/SiO₂ ratios not only changed the size of CuO particles, the orientation of crystal faces, the specific surface area, and the pore distribution in the catalyst, but also adjusted the interaction between CuO and SiO₂. In addition, different MgO/SiO₂ ratios could significantly alter the structure of the catalyst and enhance its activity, with the highest activity achieved when the MgO/SiO₂ ratio was 1:3. Experimental results showed that the spherical CuO-Bi₂O₃-MgO/SiO₂ catalyst in this study achieved a selectivity of 96.3% and a conversion rate of 94.0% when reacting with formaldehyde at a concentration of 38 wt% for 12 h. The catalyst outperformed commercial samples in terms of activity and had the same strength level and better filtration separation performance as commercial samples.