The novel α-TiO2@g-C3N4 heterostructure for ultra rapid ionic pumping and effective capacitive deionization

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Anatase titanium dioxide (α-TiO2) has been widely identified as an efficient electrode material for capacitive deionization (CDI). However, this material usually suffers from limited exposure of active sites, poor electrical conductivity and significant obstacles in ion movement due to its tendency to severely aggregate during its preparation. A novel approach to fabricate α-TiO2@g-C3N4 composite materials was proposed in this work. In detail, the 2D material g-C3N4 serves as a high-speed electron-conducting scaffold, allowing uniform loading of nanoscale α-TiO2 and exposing abundant active sites. Furthermore, g-C3N4 facilitates electron transport to nanoscale α-TiO2, enhancing charge transfer and activating previously underutilized electrochemical centers. As a result, α-TiO2@g-C3N4 composites were synthesized for the first time. Through these improvements, the prepared α-TiO2@g-C3N4 exhibits excellent desalination performance, with a high degree of efficiency in water purification. It shows an improved salt adsorption capacity (SAC) of 50.4 mg g-1 and a salt adsorption rate (SAR) of 2.7 mg g-1 min−1 in a 1.2 V, 1 mm electrode spacing, and 500 mg L-1 NaCl solution. This outstanding CDI performance surpasses most recently reported electrode materials. More importantly, this electrode showed remarkable removal efficiencies for various heavy metal ions (Ni2+, Cr3+, Cu2+, Pb2+, Fe3+ and Cd2+), indicating its significant potential for wastewater purification. The superior CDI performance of the α-TiO2@g-C3N4 composite material endows it with practical application in future.