Indirect carbonation as an efficient CO 2 sequestration strategy has received extensive attention in recent years. This study proposes a two-step leaching indirect carbonation process using NH 4 Cl and CH 3 COOH in order to combine the advantages of the two leaching agents to obtain a better experimental outcome. The experimental results show that NH 4 Cl has a high pH buffering capacity, which can increase the pH of the mixed leachate to an alkaline level. Among the 21 groups of mixed leachate, 17 were alkaline (pH > 7). The mixed leachate has a high Ca 2+ ions carbonation rate under low CH 3 COOH concentration conditions, and the carbonation rate of steel slag with a particle size of < 38 μm can reach 60% when the CH 3 COOH concentration is 0.1 M. SEM imaging showed that the CaCO 3 formed by the reaction exists in a hexagonal calcite crystal form.
Selective photocatalytic reduction of CO2 to CH3COOH is highly desirable but hindered by poor intermediate stabilization and sluggish C–C coupling. Here we report a coordination-environment engineering strategy to construct asymmetric Co active sites and induce intrinsic spin polarization by nitrogen incorporation into Co3O4. Nitrogen substitution and oxygen vacancy formation generate Co sites with distinct coordination and charge distributions, stabilizing *CO intermediates and lowering the C–C coupling barrier. Concurrently, spin polarization enhances charge carrier separation, further intensified by an external magnetic field. In situ spectroscopy and theoretical calculations confirm the synergistic role of asymmetry and spin effects in facilitating intermediate formation and CH3COOH production. The optimized N–Co3O4–X catalyst achieves a CH3COOH yield of 41.4 μmol g–1 h–1 with 95% electron selectivity under external magnetic field. This work presents a dual-modulation strategy for efficient CO2-to-C2 conversion.
Qi Guodong,Davies Thomas E.,Nasrallah Ali,Sainna Mala A.,Howe Alexander G. R.,Lewis Richard J.,Quesne Matthew,Catlow C. Richard A.,Willock David J.,He Qian,Bethell Donald,Howard Mark J.,Murrer Barry A.,Harrison Brian,Kiely Christopher J.,Zhao Xingling,Deng Feng,Xu Jun,Hutchings Graham J.
The oxidation of methane, the main component of natural gas, to selectively form oxygenated chemical feedstocks using molecular oxygen has been a long-standing grand challenge in catalysis. Here, using gold nanoparticles supported on the zeolite ZSM-5, we introduce a method to oxidize methane to methanol and acetic acid in water at temperatures between 120 and 240 °C using molecular oxygen in the absence of any added coreductant. Electron microscopy reveals that the catalyst does not contain gold atoms or clusters, but rather gold nanoparticles are the active component, while a mechanism involving surface adsorbed species is proposed in which methanol and acetic acid are formed via parallel pathways.
危险品化学品经营许可证（带存储）