Precise Structural Regulation of One-Dimensional Ni-BTC Metal–Organic Frameworks and Their Bifunctional Applications in Energy Storage and Electrocatalysis

Abstract

This study achieved the controllable synthesis of three one-dimensional Ni-BTC metal–organic framework (MOF) materials (Ni-BTC-S1, Ni-BTC-S2, and Ni-BTC-S3) by precisely regulating the hydrothermal synthesis temperature and the type of base. Through characterization techniques such as XRD, Raman, XPS, and BET, the influence laws of structural regulation on the crystallinity, coordination environment, surface chemical state, and pore structure of the materials were systematically clarified. Combined with electrochemical tests and density functional theory (DFT) calculations, the intrinsic structure-electronic property-energetic relationship among the microscopic structure, electronic properties, and energy storage/electrocatalytic performance was revealed. Experimental results showed that Ni-BTC-S3 prepared under optimized conditions had higher crystallinity, more active sites, and a larger specific surface area. It exhibited excellent rate performance and cycle stability in supercapacitors (with a specific capacity of 440 F/g at 1 A/g and a retention rate of approximately 90% after 10,000 cycles), and the assembled asymmetric supercapacitor (Ni-BTC-S3//AC) achieved a high energy density of 65 Wh/kg. At the same time, Ni-BTC-S3 exhibited excellent dual-function electrocatalytic activity for the overall water splitting, with significantly reduced overpotentials for OER and HER and Tafel slopes of 44.13 mV/dec and 91.79 mV/dec, respectively. DFT calculations confirmed that the strong surface electrostatic potential polarization, low ionic migration energy barrier, appropriate OH– adsorption strength, and position close to the Fermi level of the d-band center were the key electronic roots for the inherent electrochemical performance improvement of Ni-BTC-S3. This study, through the complete research chain of structure regulation–experimental verification–theoretical analysis, provides important references for the rational design of Ni-based MOF materials in the fields of energy storage and electrocatalysis.