Amperometric Formaldehyde Sensor Based on a Pd Nanocrystal Modified C/Co₂P Electrode

Abstract

Ultrafine Pd nanocrystals were grown on the cobalt phosphide (Co 2 P) decorated Vulcan XC-72 carbon (C/Co 2 P), which is realized by first implementing the corresponding metal precursor and then the further chemical reduction process. The as-synthesized C/Co 2 P/Pd composite was further constructed to form a gas permeable electrode. This electrode can be applied for formaldehyde (HCHO) detection. The results demonstrate that the Co 2 P nanocrystal can significantly improve the sensing performance of the C/Co 2 P/Pd electrode for catalytic oxidation of HCHO, which is considered to be attributed to the effective electron transfer from Co 2 P to Pd in the C/Co 2 P/Pd composites. Furthermore, the assembled C/Co 2 P/Pd sensor exhibits high sensitivity of 617 nA/ppm and good selectivity toward various interfering gases such as NO 2 , NO, SO 2 , CO 2 , and CO. It also shows the excellent linear response that the correlation coefficient is 0.994 in the concentration range of 1-10 ppm. Therefore, the proposed cost-effective C/Co 2 P/Pd nanocomposite, which owns advantages such as high activity and good stability, has the potential to be applied as an effective electrocatalyst for amperometric HCHO detection.

Electrochemical sensors for environmental gas analysis

“…Recent academic literature has discussed methods for preparing electrodes with high sensitivity by exploring different types of nanoporous support, and methods for measurement of gases that are not electroactive. Recent reports on different supports directed towards measurements of different gases include composites of PTFE/Pt/multiwall carbon nanotubes (H2) [17], carbon/Co2P/Pd (formaldehyde) [18], Ir-decorated hollow graphene (NH3) [19], Co3O4/reduced graphene oxide/carbon nanotubes (NO2) [20]. Electrodes formed by pyrolysis of metal-organic-framework (MOF) structures to give metals, metal phosphides or metal carbides supported on high-porosity N-or P-doped graphitised material are being explored [21].…”

Flow Injection Amperometric Measurement of Formalin in Seafood

“…The plot between the anodic current response and the square root of the scan rate provided good linearity with a linear regression equation of I pa (μA) = (7.23 ± 0.22)­v 1/2 (mV s –1 ) – (17.4 ± 2.0) (μA) ( r = 0.9977) (Figure D). The good linear relationship demonstrates that the oxidation of formalin at the PdPs-CMs/GCE was a diffusion-controlled process. , …”

“…The good linear relationship demonstrates that the oxidation of formalin at the PdPs-CMs/GCE was a diffusion-controlled process. 27 , 41 …”

“…The good linear relationship demonstrates that the oxidation of formalin at the PdPs-CMs/GCE was a diffusion-controlled process. 27,41 Formalin Sensor Optimization. In order to obtain the best electrocatalytic detection of formalin at the PdPs-CMs/ GCE in the FI-Amp system, we optimized the amount of PdPs-CMs on the electrode surface, the potential applied at the working electrode, NaOH concentration, flow rate, and sample volume.…”