Solvent-Mediated Synthesis of Two-Dimensional Conductive Metal–Organic Framework Nanoarrays for Highly Sensitive Ascorbic Acid Sensing

The rational design of catalytic materials featuring high specific surface area, precise compositional control, and ordered porosity is crucial for enhancing the performance of electrochemical sensors. Two-dimensional conductive metal–organic frameworks (2D c-MOFs) have garnered significant attention as promising candidates for sensing applications due to their intrinsic electrical conductivity, crystalline structural uniformity, and robust chemical stability. In this study, we demonstrate precise morphological control of M3(HITP)2 (M = Co, Ni) arrays on carbon cloth (CC) via solvent polarity-modulated hydrothermal synthesis. By tailoring reaction conditions, we obtained distinct nanostructures: vertically aligned nanorod arrays (Ni3(HITP)2/CC-0.3) and interconnected nanosheet networks (Co3(HITP)2/CC-3). The Ni3(HITP)2/CC-0.3 sensor exhibited remarkable ascorbic acid (AA) detection capabilities, achieving an ultrawide linear range (0–4.0 mmol·L–1) and a submicromolar detection limit (0.25 μmol·L–1). Additionally, the sensor demonstrated rapid response, outstanding selectivity, and stable performance over 30 days. This work provides a versatile platform for engineering MOF-based electrochemical sensors in the ultrasensitive detection of biomolecules.