Incorporation of edge-N into La-doped hierarchical carbon framework enables high-efficiency phosphate electrosorption: Boosting accessible active centers and bridging charge transfer paths

[Display omitted] •Novel edge-N doped hierarchical carbons were firstly reported for P electrosorption.•The edge-N strategy endowed more accessible active centers and conductive efficiency.•The LNPC900 electrode showed a superior phosphate removal capacity of 533.06 mg g−1.•The system performed well in natural water purification with low P concentration.•The coupling of electrical capacitance and chemical interactions were achieved. Achieving high-efficiency removal of phosphate has been an urgent issue to combat eutrophication and meet ever-stricter emission standards. Electro-assisted adsorption, a mild electrochemical technology, demonstrated great potential for wastewater treatment owing to the merits of considerable removal performance, facile operation, and energy efficiency. Exploring and boosting the properties of electrode materials is exceedingly vital for technological advancement. In this study, the novel edge-N decorated La-doped hierarchical carbon composites (LNPCs) were developed via in-situ nucleation and one-pot pyrolysis strategy as phosphate capture electrodes. The LNPC900 electrode exhibited an ultrahigh phosphate removal capability of 533.06 mg PO43- g−1 at 1.2 V, surpassing most of the reported electrode materials. Furthermore, this electrochemical system also performed well in the purification of natural river water with low phosphate concentration, where the treated concentration was below the first-class emission standard in China (0.5 mg P L−1). Comprehensive analysis and theoretical calculations indicate that the synergistic property of edge-N and small graphitic carbon nanodomains ensured more accessible active centers and conductive efficiency. The superb phosphate removal capability mainly originated from the coupling contribution of the electrical double layer capacitance, ligand exchange, and electrostatic attraction. This study possesses insight into the theoretical basis for the practical application of phosphate electrosorption and provides a new level of the technology.