1 of 6

Molybdenum Coupled Electrochemical Sensing Systems

Andie R. Veeder (University of Arkansas, Chemical Engineering )

Elizabeth V. Schell (Electrical and Systems Engineering)

Mark G. Allen (Electrical and Systems Engineering)

​

1

This material is based upon work supported by the IoT4Ag Engineering Research Center funded by the National Science Foundation (NSF) under NSF Cooperative Agreement Number EEC-1941529.  Any opinions, findings and conclusions, or recommendations expressed in this material are those of the author(s), and do not necessarily reflect those of the NSF.

IoT4Ag

JULY 28, 2021

REU PRESENTATION

2 of 6

Introduction and Problem Statement

To improve the efficiency of crop production, we are developing devices to conduct widespread agricultural monitoring of nutrients and environmental factors. Electronics for this application must be low-cost, able to deliver easily accessible data directly to farmers, and disappear after their functional lifespan.

​

Overarching topics addressed this summer:

  • Electrochemical sensors and power sources
  • Transient materials
  • Energy output dependent on concentration of phosphate

​

2

Figure 1: Schematic of overall goal

IoT4Ag

JULY 28, 2021

REU PRESENTATION

3 of 6

Overview of the Technical Approach

  • Molybdenum has shown selectivity towards phosphate and is presently used in dissolvable electronics
  • Test the possibility of a phosphate sensor made out of transient materials that detects plant available phosphates (PAPs) found in soil
  • Two different approaches
    • potentiometric
    • amperometric

​

3

Figure 3: Experimental set-up

Figure 2: Electrochemical cell schematic

IoT4Ag

JULY 28, 2021

REU PRESENTATION

4 of 6

Results

​

Figure 4: Open circuit potential results

​

Figure 5: Cyclic voltammetry results after sweep from 0.5 V to 1.5 V

4

IoT4Ag

JULY 28, 2021

REU PRESENTATION

5 of 6

Results continued

Sensitivity:

  • 0.8179 dec/dec

​

Limit of detection:

  • 1e-4 M

​

5

Figure 6: Chronoamperometry results

Figure 4: Mo electrode in 1e-1 M PBS after voltage of 1.2 V applied

Figure 5: Au electrode in 1e-1 M PBS after voltage of 1.2 V applied

IoT4Ag

JULY 28, 2021

REU PRESENTATION

6 of 6

Summary

The feasibility of a phosphate sensor composed of transient materials has now been confirmed, and further research can be conducted in regard to:

​

  • miniaturizing the sensor
  • converting electric current into signals
  • constructing packaging out of biodegradable materials

6

IoT4Ag

JULY 28, 2021

REU PRESENTATION