Nickel–Platinum Double-Atom Catalysts for Real-Time Dopamine Detection in Sweat and Potential Applications in Flexible Zinc–Air Batteries

Dopamine plays an important function in the neurological system, and its detection in sweat has received interest due to its noninvasive nature. However, the low concentration of dopamine in sweat has hampered the development of current wearable sensors. To address this issue, we devised a novel detection approach based on nickel-platinum double-atom catalysts (Ni/Pt DACs), which exhibit exceptional oxidation properties. This approach extends the detection range (10 nM to 750 μM) and reduces the detection limit to 5.48 nM, covering the physiological range of dopamine concentrations in human sweat. Experimental results and density functional theory (DFT) simulations show that doping with platinum single atoms lowers the activation energy of the reaction rate-determining step (RDS), increasing the catalytic efficiency of Ni/Pt DACs for dopamine. Furthermore, using a hydrophilicity-modified four-inlet microfluidic device on volunteer skin, we were able to measure dopamine concentrations in human sweat in real time using cellphones. We also conducted a preliminary investigation into the application potential of Ni/Pt DACs in flexible zinc-air batteries (ZABs), including DFT theoretical analysis. This discovery not only increases dopamine detection technology in sweat, but also sheds fresh light on the use of diatomic catalysts in zinc-air batteries.