Synergistic promotion of industrial-grade water splitting by ruthenium clusters and phosphidated Fe-based MOF

Developing robust electrocatalysts capable of operating at ampere-grade current densities is imperative for practical water electrolysis. Herein, we report a bifunctional electrocatalyst with minimal Ru metal (0.78 wt%) anchored on the phosphidated Fe-based metal-organic framework (Ru@P-FeMOF). Experimental and theoretical analyses reveal that Ru nanoclusters, with a narrow size distribution of 1.6–2.8 nm, are uniformly deposited on the interwoven P-FeMOF nanosheets, which are vertically arranged on the substrate. Such a structure provides abundant active sites and facilitates interfacial charge transport due to the optimized d-band center and the lowest energy barrier of the rate-determining step, significantly boosting hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). It is proved that Ru nanoclusters are more conducive to HER, while the presence of Fe 2 P coupling with FeMOF contributes more to reducing O 2 desorption free energy. The fabricated catalyst exhibits superior electrochemical activity and high stability in alkaline water electrolysis. Only 20 and 184 mV of overpotentials are required for HER at 10 and 1000 mA cm −2 , respectively, while 171 mV @ 50 mA cm −2 and 258 mV @ 1000 mA cm −2 for OER in 1 M KOH. Moreover, Ru@P-FeMOF exhibits outstanding durability with negligible degradation after running 10,000 cycles or over 200 h. The cell voltage with Ru@P-FeMOF as both anode and cathode in overall water splitting is as low as 1.43/1.74 V at 10/1000 mA cm −2 , showing excellent performance at industrial-level current densities.