Bismuth Nanoclusters/Porous Carbon Composite: A Facile Ratiometric Electrochemical Sensing Platform for Pb²⁺ Detection with High Sensitivity and Selectivity

Abstract

In this work, a ratiometric electrochemical sensor was constructed for the detection of Pb 2+ based on a bismuth nanocluster-anchored porous activated biochar (BiNCs@AB) composite. BiNCs with loose structure and AB with abundant oxygen-containing functional groups are favorable for Pb 2+ adsorption and preconcentration; meanwhile, porous AB provides more mass transfer pathways and increases electronic and ion diffusion coefficients, realizing high sensitivity for Pb 2+ detection. At the same time, BiNCs were proposed as an inner reference for ratiometric electrochemical detection, which could greatly enhance the determination accuracy. Under optimized experimental conditions, the anodic peak current ratio between Pb 2+ and BiNCs exhibited a good linear relationship with the concentration from 3.0 ng/L to 1.0 mg/L. The detection limit can be detected down to 1.0 ng/L. Furthermore, the proposed sensor demonstrated good reproducibility, stability, and interference resistance, as well as satisfactory recoveries for the detection of Pb 2+ in real samples.

Recent Advances of Biochar-Based Electrochemical Sensors and Biosensors

“…Summarizing the recent works about metallic nanoparticles/biochar composites, the key effect of biochar is that its porous structure can effectively disperse metallic nanoparticles, and thus make the nano-sized metal provide more activated sites and show enhanced catalytic, redox, or conductive capacities. Therefore, the preparation of metallic nanoparticles (bismuth [ 38 ], mercury [ 39 ], cobalt [ 40 ], and gold [ 11 ]) and biochar nanocomposite yields materials with an excellent analytical and electrochemical performance, combining biochar and metal features in the same device [ 41 ].…”

“…Another work concerning the detection of Pb 2+ was reported by Zou et al [ 38 ] Considering the low electrical conductivity and easy agglomeration of Bi particles, porous activated biochar (AB) with the merits of high electrical conductivity, large surface area, and good chemical stability was chosen as the support material. In summary, a ratiometric electrochemical platform based on the BiNCs@AB-modified electrode was constructed for the analysis of Pb 2+ in a linear range from 3.0 ng·L −1 to 1.0 mg·L −1 with an LOD of 1.0 ng·L −1 .…”

A facile ratiometric electrochemical sensing platform with in‐situ electropolymerized thionine on effective sensing of 5‐hydroxytryptamine

“…Because of their superior self-calibration ability, the development of ratiometric electrochemical sensors has caused the increasing interest to offer the possible application in complicated test conditions. Currently, few metal ions like Bi(III) [16,26] and some redox species as ferrocene (Fc) [27][28][29], thionine (Th) [30], and methylene blue (MB) [31][32][33], are mainly employed as electrochemical signal indicators. Niu et al developed a stable ratiometric electrochemical sensor with the nitrogen doped bimetallic CoNi nanomaterials and MB was used as the internal reference, which realized for detecting p-phenylenediamine in commercial hair dyes [34].…”

Dual Signal-Enhanced Electrochemiluminescence Strategy Based on Functionalized Biochar for Detecting Aflatoxin B1

“…Furthermore, based on our previous investigation and summarization [ 26 ], we found that porous activated biochar with the merits of good chemical stability and large surface area was appropriately chosen as the support material [ 27 ]. Essentially, the biochar obtained from renewable biomass through pyrolysis or carbonization processes under a low-concentration oxygen atmosphere is porous, eco-friendly, and low-cost [ 28 , 29 ].…”