Prompt Description

Multilayer graphene was dispersed in 50 ml of deionized water and sonicated until uniformly dispersed. Urea was added and magnetically stirred until completely dissolved. The mixed solution was sealed in a 100 mL Teflon-lined autoclave and hydrothermally reacted at 160°C for 3 hours. The product was then centrifuged, washed, and vacuum-dried overnight. Nickel nitrate hexahydrate and manganese nitrate tetrahydrate were weighed, added to deionized water, and magnetically stirred. NaOH was added dropwise to the beaker until the solution pH was adjusted to 9-10, followed by magnetic stirring for 30 min. The N-MLG was placed in 10 ml of DI water and magnetically stirred for 30 min. The N-MLG suspension was poured into the above homogeneous solution, and the mixture was transferred to a Teflon reactor. The mixture was heated at 180°C for 16 hours, and repeatedly washed to remove residual reagents and impurities. The washed product was dried in a vacuum drying oven (60°C, 12 h). The N-MLG@Ni-Mn LDH dispersion (5 μL, 5 mg/mL) was drop-casted onto the surface of a pretreated SPE working electrode and dried at room temperature to obtain N-MLG@Ni-Mn LDH/SPCE. 0.121 g of L-cysteine (10 mM) was weighed and dissolved in 10 mL of 0.1 M ABS buffer (pH=5) by sonication for 10 min. The modified electrode was immersed in the above solution and incubated at 4°C in the dark. The electrode was removed, rinsed with deionized water to remove unbound L-cysteine, and labeled as N-MLG/Ni-Mn LDH/L-Cys/SPCE.