A free-standing and flexible phosphorus/nitrogen dual-doped three-dimensional reticular porous carbon frameworks encapsulated cobalt phosphide with superior performance for nitrite detection in drinking water and sausage samples

• Published in: Sensors and actuators. B, Chemical Chemical, 2020-10, Vol.321, p.128541, Article 128541
• Main Authors: Zhu, Di, Zhen, Qingfang, Xin, Jianjiao, Ma, Huiyuan, Tan, Lichao, Pang, Haijun, Wang, Xinming
• Format: Article
• Language: English
• Subjects: 3D porous carbons; Carbon; Cobalt; CoPx nanoparticles; Drinking water; Electrochemical analysis; Hydrothermal; Nanocomposites; Nanoparticles; Nitrite sensor; Nitrogen; Nitrogen dioxide; Phosphating (coating); Phosphidation treatment; Phosphides; Phosphorus; Polyacrylonitrile; Structural hierarchy
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2020.128541

The nanoparticles of CoPx anchoring to honeycomb-like P,N co-doped 3D reticular porous carbon framework was designed and fabricated by using PAN as nitrogen-containing carbon source and hypophosphite as P source. This electrocatalyst shows excellent sensing performance for nitrite, originating from the unique multi-level porosity and hierarchical connectivity of P,N co-doped carbon network, and superb electrocatalytic activity of uniformly dispersed CoPx NPs. [Display omitted] •Novel nanocomposite of CoPx embedded into 3D P,N doped carbon framework was proposed.•Encapsulating CoPx into porous carbon framework enhance electrocatalytic activity.•The nanocomposite has both unique 3D porous structure and hierarchical connectivity.•Well structural virtues and synergistic effect endow high nitrite sensing property.•Acceptable recovery in real sample indicated its real application value. An assembly and self-template strategy is presented for the synthesis of cobalt phosphide nanoparticles (CoPx, x = 1, 2) embedded into 3D phosphorus/nitrogen co-doped reticular porous carbon frameworks (denoted as CoPx@P,N–RPCs) utilizing polyacrylonitrile (PAN) as the in situ nitrogen doping carbon source and hypophosphite as phosphorus source via hydrothermal method and subsequent phosphorization. The obtained CoPx@P,N–RPCs nanocomposite possesses the inherent features of both unique 3D porous structure and hierarchical connectivity, providing highly efficient pathways for electron, ion, and mass transport. The unique P,N co-doped carbon network confines nanostructural CoPx into the microstructural carbon network, which prevents them from aggregating, improves the conductivity of CoPx, meanwhile alleviates large volume expansion/contraction effect, thus results in high electrochemical performance and cycling durability. Benefiting from its unique structural advantages, the CoPx@P,N–RPCs nanocomposite exhibits excellent electrochemical performance for nitrite (NO2–) detection with a wide linear range of 10 nM to 1.184 mM, a low detection limit of 5 nM, and a very high stability, which is better than most nitrite sensors reported previously. Importantly, the nitrite level can be determined by the resulting sensor in food and drinking water with excellent recoveries, implying its feasibility for realistic application.