Dendritic Cell-Inspired Designed Architectures toward Highly Efficient Electrocatalysts for Nitrate Reduction Reaction.

Electrocatalysis for nitrate reduction reaction (NRR) has recently been recognized as a promising technology to convert nitrate to nitrogen. Catalyst support plays an important role in electrocatalytic process. Although porous carbon and metal oxides are considered as common supports for metal-based catalysts, fabrication of such architecture with high electric conductivity, uniform dispersion of nanoparticles, and long-term catalytic stability through a simple and feasible approach still remains a significant challenge. Herein, inspired by the signal transfer mode of dendritic cell, an all-carbon dendritic cell-like (DCL) architecture comprising mesoporous carbon spheres (MCS) connected by tethered carbon nanotubes (CNTs) with CuPd nanoparticles dispersed throughout (CuPd@DCL-MCS/CNTs) is reported. An impressive removal capacity as high as 22 500 mg N g-1 CuPd (≈12 times superior to Fe-based catalysts), high nitrate conversion (>95%) and nitrogen selectivity (>95%) are achieved under a low initial concentration of nitrate (100 mg L-1 ) when using an optimized-NRR electrocatalyst (4CuPd@DCL-MCS/CNTs). Remarkably, nitrate conversion and nitrogen selectivity are both close to 100% in an ultralow concentration of 10 mg L-1 , meeting drinking water standard. The present work not only provides high electrocatalytic performance for NRR but also introduces new inspiration for the preparation of other DCL-based architectures.