N and P co-doped MXenes nanoribbons for electrodeposition-free stripping analysis of Cu(II) and Hg(II).

The present electrochemical stripping analysis (ESA) for multiple heavy metal ions (HMI) generally requires an electrodeposition process at a very low potential below -1.0 V, which inevitably makes the sensing procedures more complex, inefficient and power-wasting. Meanwhile, the emerging MXenes rising-star materials have been studied in various fields recently. While there are only few reports focusing on the heteroatom doping of MXenes, especially no doping-MXenes for electroanalysis. Based on these issues, a novel multifunctional heteroatoms-doped MXenes nanomaterial, N and P co-doped Ti3C2Tx MXenes nanoribbons (N,P-Ti3C2TxR), was prepared herein for the first time, and then N,P-Ti3C2TxR was used as electrode material to propose an electrodeposition-free ESA strategy for multiple HMI (Cu2+, Hg2+). Owing to the unique spontaneous adsorption and reducing capacities of N,P-Ti3C2TxR towards Cu2+ and Hg2+ coupled with the excellent sensing performances, Cu2+ and Hg2+ can undergo self-reduction to be preconcentrated on N,P-Ti3C2TxR surface with the form of Cu0 and Hg0, thus a simple and ultrasensitive electrodeposition-free ESA platform was developed successfully for the simultaneous detection of Cu2+and Hg2+. This work opened a new pathway for the detection for multiple HMI and the preparation/application of heteroatoms doping MXenes.