Efficient and durable capacitive recovery of heavy metal ions over the atomically dispersed nickel- and nitrogen-doped carbon-coupled titanium nitride

The green and sustainable capacitive deionization (CDI) gains enormous promise as a robust energy technology for harnessing abundant heavy metal wastewater contaminants to provide renewable freshwater resources. Although the transition metal nitrides with tunable and diverse derivatives are potential Faradaic-active CDI electrode materials, their inadequate removal efficiency and cyclic durability still hinder the practical heavy metal capture application. Herein, a novel highly dispersed single Ni atom-embedded N-doped nanocarbon encapsulated TiN nanorod-assembled 3D flower-like network integrated with the flexible carbon cloth substrate to construct a self-supported and flexible Ni SAs/N-C@TiN electrode material is designed for the lowconcentration heavy metal ion removal. Profiting from the synergy of specific microstructure textures (open framework, high porosity, and hierarchical pore alignment), enhanced charge density distribution in the active adsorption sites), and superior electrochemical conductivity, the Ni SAs/N-C@TiN electrode realizes the exceptional removal capability and remarkable cycling lifespan, and the ex-situ XPS analysis combined with the CV techniques illustrate the predominantly pseudocapacitive capture mechanism. It delivers an average removal efficiency attains around 97 % towards the simulated low-concentration wastewater systems along with the high saline feature along with the excellent capacitance durability over 20,000 GCD cycles, certifying its great prospects for practical wastewater purification.