Tungsten Carbide Nanotubes Supported Platinum Nanoparticles as a Potential Sensing Platform for Oxalic Acid

Supported tungsten carbide is an efficient and
vital nanomaterial for the development of high-performance,
sensitive, and selective electrochemical sensors. In this work,
tungsten carbide with tube-like nanostructures (WC NTs)
supported platinum nanoparticles (PtNPs) are synthesized and
explored as an efficient catalyst toward electrochemical
oxidation of oxalic acid for the first the time. The WC NTs
supported PtNPs modified glassy carbon (GC) electrode is
highly sensitive toward the electrochemical oxidation of oxalic
acid. A large decrease in the oxidation overpotential (220 mV)
and significant enhancement in the peak current compared to
unmodified and Pt/C modified GC electrodes have been
observed without using any redox mediator. Moreover, WC NTs supported PtNPs modified electrode possessed wide linear
concentration ranges from 0 to 125 nM and a higher sensitivity toward the oxidation of oxalic acid (80 nA/nM) achieved by the
amperometry method. The present modified electrode showed an experimentally determined lowest detection limit (LOD) of 12
nM (S/N = 3). Further, WC NTs supported PtNPs electrode can be demonstrated to have an excellent selectivity toward the
detection of oxalic acid in the presence of a 200-fold excess of major important interferents. The practical application of WC NTs
supported PtNPs has also been demonstrated in the detection of oxalic acid in tomato fruit sample, by differential pulse
voltammetry under optimized conditions.

负载型碳化钨（Supported tungsten carbide）是用于开发高性能、高灵敏且高选择性电化学传感器的高效关键纳米材料。本研究首次合成了负载铂纳米颗粒（PtNPs）的管状纳米结构碳化钨（WC NTs），并将其作为高效催化剂用于草酸的电化学氧化反应。研究发现，负载WC NTs的PtNPs修饰玻碳（glassy carbon, GC）电极对草酸的电化学氧化具有极高的灵敏度：相较于未修饰玻碳电极与Pt/C修饰玻碳电极，该修饰电极可使氧化过电位大幅降低220 mV，且峰电流显著提升，全程无需使用任何氧化还原媒介体。此外，采用安培法检测时，该修饰电极的草酸氧化检测线性浓度范围宽达0~125 nM，灵敏度高达80 nA/nM，实验测得的最低检出限（limit of detection, LOD）为12 nM（信噪比S/N=3）。进一步实验表明，即便存在200倍过量的主要常见干扰物，该负载WC NTs的PtNPs修饰电极仍可对草酸实现优异的选择性检测。最后，本研究在优化条件下采用差分脉冲伏安法，将该材料成功应用于番茄果实样品中草酸的实际检测。