Dual Metal Synergy-Induced d-Band Modulation in ZIF-7 Nanosheets for Efficient pH-Universal Electrocatalytic Hydrogen...

The development of robust and cost-effective electrocatalysts for the hydrogen evolution reaction (HER) across universal pH remains a practical challenge due to sluggish kinetics, low electrical conductivity, and poor structural rigidity of pristine MOFs. Herein, an approach has been proposed to improve the electrocatalytic properties of ZIF materials by electronic modulation via systematic Fe doping, which serves as an active site for hydrogen adsorption and stabilizes HER intermediates within the 2D ZIF-7 framework. The optimized electrocatalyst preserves the pristine ZIF-7 (III) 2-D morphology upon Fe-doping, with a stacked layered nanosheet morphology that has been investigated for HER performance across universal pH conditions. The optimized 15% Fe-doped ZIF-7 (15Fe-ZIF-7) exhibits superior HER activity in both alkaline and acidic media compared to pristine ZIF-7 and 5Fe-ZIF-7, with overpotentials of 79.9 and 93.5 mV at -10 mA cm^-2, respectively. 15Fe-ZIF-7 also exhibits promising HER activity in neutral medium, with prolonged stability over 100 h of chronopotentiometry (CP) stability in all media. DFT calculations revealed that Fe doping induces dual-metal synergy via d-band modulation, facilitating faster charge transfer and hydrogen adsorption by lowering the energy barrier and providing sites with lower ΔG_H*. Thus, providing material for a pH-universal HER electrocatalyst.