Reagent-free electrochemical sensor for reactive chlorine species detection on laser-induced graphene
A bioinspired copper-sulfide catalyst on 3D porous laser-induced graphene enables reagent-free, in-line electrochemical detection of reactive chlorine species (RCS) such as hypochlorite. The technology targets low-cost, small-footprint, low-power sensors for water quality monitoring, industrial process control, and environmental safety applications.
Overview
This technology offers a reagent-free electrochemical sensing platform for the selective and sensitive detection of reactive chlorine species (RCS), including hypochlorite, in aqueous environments. Inspired by chlorine-responsive biological mechanisms in bacteria, the approach uses copper sulfide (Cu₂S) catalyst layers deposited on three-dimensional porous laser-induced graphene (LIG) electrodes fabricated directly on flexible polyimide substrates. The result is a low-cost, compact, low-power sensor capable of detecting RCS without the need for added reagents, supporting continuous in-line monitoring for water treatment, industrial disinfection processes, and environmental safety applications.
Technical specifications
Core sensing principle:
- Sulfur-based catalyst layers drive redox reactions of RCS at the electrode surface
- Copper sulfide (Cu₂S) provides selectivity toward chlorine species through a Fenton-like reaction mechanism
- Detection is achievable at zero applied voltage, minimizing power requirements
Electrode design and fabrication:
- Laser-induced graphene (LIG) is patterned directly on polyimide film, creating a porous 3D carbon network
- Copper is deposited onto the LIG and sulfurized in place to form Cu₂S catalyst sites
- The porous LIG structure increases active surface area, supporting high sensitivity
- Plastic-substrate construction enables low-cost, flexible device formats
Performance demonstrated to date:
- Detection of 1 ppm sodium hypochlorite (NaOCl) in phosphate-buffered saline at pH 7.4 on planar graphene ink electrodes
- Zero-applied-voltage operation confirmed in proof-of-concept testing
Planned validation and development:
- Optimization of deposition and sulfurization conditions for sensitivity, selectivity, and material stability
- Flow-cell testing under continuous operation
- Multi-modal signal acquisition including current-voltage and impedance measurements
- Advanced data analytics to maximize detection accuracy
Technology readiness level
The technology is at an early-to-mid stage of development. A proof of concept has been demonstrated on planar graphene ink substrates, showing detection of 1 ppm NaOCl at zero applied voltage. The next phase focuses on translating the approach to laser-induced graphene on polyimide substrates, optimizing the Cu₂S catalyst, and validating sensor performance under flow conditions with multi-modal readouts and data analytics. The technology is not yet commercially available and requires further development and field validation before deployment.
About Penn State University
Penn State University is a comprehensive public land‑grant research university with a large multi‑campus footprint across Pennsylvania. Industry engages through a research and technology park adjacent to the flagship campus that houses corporate R&D, co‑located labs, and flexible collaboration space, as well as a statewide extension network that enables field testing, demonstration, and workforce reach. Integration with a major hospital system supports clinical translation, and an applied research laboratory fosters mission‑driven partnerships with government and industry sponsors. Research is supported by competitive federal funding from agencies such as NSF, NIH, DOE, USDA, DoD, and NASA. A dedicated technology transfer office manages IP, licensing, and startup formation to accelerate commercialization.
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