Electrodeposited Manganese Dioxide/Activated Carbon Composite As a High-Performance Electrode Material for Capacitive Deionization

Electrode materials are a crucial component for achieving high desalination performance via capacitive deionization (CDI). In the present work, we have successfully fabricated a manganese dioxide (MnO₂)/activated carbon (AC) composite electrode using an anodic electrodeposition technique. Surface characterization confirms the presence of electrodeposited MnO₂ on the AC surface with an amorphous structure and improved wetting behavior. Cyclic voltammetry and galvanostatic charge/discharge measurements indicate that the MnO₂/AC composite electrode exhibits a high specific capacitance (77.6 F g^–1 at 5 mV s^–1), rate capability, and excellent cycling reversibility for capacitive charge storage. Furthermore, the salt electrosorption capacity is investigated using batch mode experiments at a working voltage of 1.0 V in a 0.01 M NaCl solution. The MnO₂/AC composite electrode presents a superior electrosorption capacity of 9.3 mg g^–1, which is approximately 1.6-fold higher than that of the pure AC electrode (5.7 mg g^–1). This significant improvement can be attributed to the mixed capacitive-Faradaic process, corresponding to the combination of the double-layer charging of the high specific surface area (625 m² g^–1) and the pseudocapacitive redox reaction of MnO₂. Therefore, the electrodeposited MnO₂/AC composite is a potential electrode material for high-performance CDI

Cellulose Framework Directed Construction of Hierarchically Porous Carbons Offering High-Performance Capacitive Deionization of Brackish Water

We demonstrate a cellulose-templating method for synthesizing a hierarchically porous carbon electrode that is capable of high-performance capacitive deionization (CDI). Hierarchically porous carbons (denoted as HPC-<i>X</i>, <i>X</i> = 500–900 °C) of an exceptionally high surface area up to 2535 m² g^–1 and wide-range pore size distribution (macro-, meso-, and micropores) were obtained via the pyrolysis of macroporous cellulose fibrous-templated resorcinol-formaldehyde-triaminopyrimidine (RF-TPF) polymers. The improved electrosorption performance of HPC-800 electrode can be ascribed to the enhanced specific surface area, favorable hierarchical structure, and excellent capacitive electric double layer behaviors

Mesoporous TiO₂ Embedded with a Uniform Distribution of CuO Exhibit Enhanced Charge Separation and Photocatalytic Efficiency

Mixed metal oxide nanoparticles have interesting physical and chemical properties, but synthesizing them with colloidal methods is still challenging and often results in very heterogeneous structures. Here, we describe a simple method to synthesize mesoporous titania nanoparticles implanted with a uniform distribution of copper oxide nanocrystals (CuO@MTs). By calcining a titanium-based metal–organic framework (MIL-125) in the presence of Cu ions, we can trap the Cu in the TiO₂ matrix. Removal of the organic ligand creates mesoporosity and limits phase separation so that tiny CuO nanocrystals form in the interstices of the TiO₂. The CuO@MTs exhibits superior performance for photocatalytic hydrogen evolution (4760 μmol h^–1) that is >90 times larger than pristine titania