SitS NSF-UKRI: Real-time and Continuous Monitoring of Phosphates in the Soil with Graphene-Based Printed Sensor Arrays

Lead Research Organisation: University of Sheffield
Department Name: Chemistry


Phosphorus, one of the major three nutrients for plants, is required for plant growth, and it serves as an indicator for global environmental sustainability. It is important to understand the variations of phosphate in soils and soil-water systems in order to address a number of global challenges such as food production and regulating fertilizer applications for crops grown in various soil conditions and climate regimes. The goal of this research project is to use the latest graphene-based technology to develop a low-cost sensor capable of real-time monitoring of the phosphorus content in soil. This collaborative project between researchers at the U.S. institutions of Kansas State University and the University of Alabama at Huntsville, and the U.K. institution of the University of Sheffield, will be conducted by an interdisciplinary team with expertise in soil and water science, geology, electrical engineering, and the fundamental chemistry and physics of soil-graphene interactions. Development of such sensors will enable farmers to choose the right amount of fertilizer to apply to the fields.

This research project aims to develop an additively-manufactured graphene sensor array and a portable wireless system for continuous in-field monitoring of electrochemical signals. Such a system would be applied to the mapping of soil phosphates in diverse agricultural landscapes in the US Midwest (Kansas) and the UK East Midlands (Derbyshire Dales and Peak District). Structurally and chemically tailored graphene materials will be used to print graphene sensors with quasi-three-dimensional and porous graphene morphologies. The materials will be designed to achieve high electrical conductivity as well as reversible and high electron charge-transfer characteristics when exposed to soil phosphates. A fundamental understanding of phosphate ion binding with various graphene morphologies will be gained using state-of-the-art ultrafast laser spectroscopy and high-end computational modeling. A Bluetooth communication module with an Arduino platform will be constructed and interfaced with the sensor arrays for sensor data acquisition. Controlled environmental testing of spatial and temporal variations of phosphate ions over other interfering ions will be carried out at specific sites in Kansas and at Europe's largest controlled environment P3-facility housed at the University of Sheffield. The fundamental sensing characteristics and drift optimization with temperature, humidity, salinity, and soil pH will be identified and optimized for reliable data collection. Soils ranging from coarse calcareous to loamy montmorillonitic and silicate-rich soils in two countries will be utilized as testbeds to measure the sensing capabilities of the printed arrays. Furthermore, the project will explore the detection of phosphates over other interfering ions in soils, such as nitrates, silicates, and heavy metals, by using chemically-functionalized graphene sensors. This research will help to strengthen the national and economic security of both the U.S. and the U.K. and will strengthen the future workforce by bridging the gaps between science, technology, agriculture, and environmental disciplines through the training of graduate students, undergraduate students, and postdoctoral scientists.

Planned Impact

The project will generate new knowledge in multiple specialized areas (graphene-based sensor, phosphate sensing, soils monitoring). These outputs will be directly beneficial both for academia and for industry. Since the project involves development of novel graphene sensors and characterisation of graphene materials, the immediate intellectual output of the research will be of great interest to researchers in the field of graphene science and technology. Among the major stakeholders of the project are research communities working on graphene-based sensors, such as the Centre for Graphene Science at the University of Exeter and the National Graphene Institute at the University of Manchester. These groups will be contacted at the start of the project. The goal is to create links between the different centres to keep up-to-date with the latest development in this rapidly growing field as well as to inform them about the project outcomes. Our research results will be disseminated through publications in high-quality journals and presentations in leading conferences. The project also involves development of a functional device capable of acquiring, storing and sending the measurements data. This technology can be directly adopted in other research laboratories involved in small molecules/heavy metal sensing. In this aim, it is planned that informal demonstrations and workshops will be performed in research groups who use similar techniques. To this end, the team will benefit from existing collaborations and will develop further collaborations through interactions with research centres and hubs mentioned above. The team will endeavour to commercialise these technological innovations. Commercial opportunities will be assessed by both the University of Sheffield and Kansas State University and University of Alabama Commercialisation Teams, which work in close collaboration with startup companies specialised in commercialisation of university intellectual property.

Economy, health and society
This project is expected to be an integral part of a transition toward precision farming. In order to enable this transition, the team will work in close collaboration with the P3 institute and Grantham Centre for Sustainable Futures at the University of Sheffield. This collaboration will help translate the knowledge gained from the project into practical guidelines used to inform policy and guidelines for related industries. These policies and guidelines will in turn affect the wider society.
In terms of immediate societal impact, the University of Sheffield, and more specifically, the departments of Chemistry and Animal and Plant Sciences are involved in regular outreach activities such as school visits, open days, STEM activities, participation in charity events. Members of the team have a track record of participation in activities dedicated to popularization of science and, in particular, to schoolchildren. Because the project includes the fabrication of devices that are applied to real-life environments, it is ideally suited for outreach activities that are appealing to the public.

The people who will most immediately benefit from this project are postdoctoral research associates (PDRAs), as well as current and future PhD, master and undergraduate students who will work alongside the PDRAs on related projects. The PDRAs and students will be trained to use and develop some of the most sophisticated tools available today within a vibrant and interdisciplinary environment. The PDRAs have access to a wide range of transferable skills training at the University of Sheffield, such as problem solving, giving presentations, writing for publication, training in grant writing skills, industry engagement and policy making. The novelty of the materials, equipment and analytical tools, as well as the interdisciplinary nature of the project will provide the participants with a valuable set of technical and transferable skills.


10 25 50
Description We were able to characterise new graphene-based materials (aerosol gels), and found that the oxygen content was primarily affecting the materials electronic properties, while its 3D structure had little to no effect.
The findings are directly informing related project which uses carbon-based material for sensing (along with MONs) and catalysts (C-foam).
Exploitation Route Primary results will be published. One paper submitted to JPCC, and two more that are drafted.
Sectors Agriculture, Food and Drink,Chemicals,Environment

Description The findings are used for outreach purposes.
First Year Of Impact 2021
Sector Education
Impact Types Societal

Description NERC discipline hopping
Amount £9,000 (GBP)
Organisation University of Sheffield 
Sector Academic/University
Country United Kingdom
Start 02/2022 
End 03/2022
Description SitS ECR Placement
Amount £7,800 (GBP)
Organisation University of Sheffield 
Sector Academic/University
Country United Kingdom
Start 04/2021 
End 08/2021
Title Long-time TA 
Description In partnership with Dr. Jenny Clark, the PDRA helped develop a transient absorption spectroscopy setup with time window spanning the ns-ms range. 
Type Of Material Improvements to research infrastructure 
Year Produced 2020 
Provided To Others? No  
Impact Publications are to come 
Description Hadi Alqahtani: Irradiated thin film metal oxides 
Organisation King Saud University
Country Saudi Arabia 
Sector Academic/University 
PI Contribution We will provide with ultrafast characterisation of the films in order to correlate our result with their catalytic properties
Collaborator Contribution Will provided with thin films
Impact The collaboration just started; we will receive the first samples within the coming weeks.
Start Year 2020
Description Jona Foster: Functionalising graphene using MONs 
Organisation University of Sheffield
Country United Kingdom 
Sector Academic/University 
PI Contribution My research team will provide will electronic characterisation of the newly build materials.
Collaborator Contribution Together, we secured an EPSRC DTP studentship who will produce Metal Organic Nanosheet to functionalise the graphene substrate.
Impact First MONs have been synthetized, but not yet characterized.
Start Year 2020
Description Prof Craig Banks' electrodes 
Organisation Manchester Metropolitan University
Country United Kingdom 
Sector Academic/University 
PI Contribution We provided with novel MONs as well as characterisation of the final electrode.
Collaborator Contribution They provided with the graphene-base ink and access to printer to print electrodes.
Impact We have made a series of novel graphene-MON electrodes
Start Year 2021
Description Sami Rtimi: antibacterial thin film metal oxides 
Organisation Swiss Federal Institute of Technology in Lausanne (EPFL)
Country Switzerland 
Sector Public 
PI Contribution Provided with electron dynamic characterisation. While the collaboration started before this award, the award enabled the collaboration to develop further.
Collaborator Contribution Provided with samples
Impact One paper already published. And we have the data for two more publications.
Start Year 2015
Description I'm a Scientist, Get me out of here! 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Outreach online platform where (registered) students can ask science-related questions.
Year(s) Of Engagement Activity 2020
Description Tapton Secondary School 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Outreach talk
Year(s) Of Engagement Activity 2021