Ultrafine ruthenium-iridium alloy nanoparticles well-dispersed on N-rich carbon frameworks as efficient hydrogen-generation electrocatalysts

Abstract

The production of green energy, in this case, hydrogen (H2), from water electrolysis highly depends on the rational design of highly efficient yet cost-effective electrocatalysts for the hydrogen evolution reaction (HER). Precious-metal-based materials offer particularly prominent catalytic activities but suffer from the high cost. Thus, it is strongly desirable to develop low-metal-content composites as catalysts. In addition, fabricating an alloyed structure can greatly enhance the performance through synergy. Here, a novel nanohybrid of nanostructured RuIr alloys (~3.87 nm) with a low loading uniformly decorated on a highly porous and N-rich carbon matrix (RuIr@NrC) is constructed through a one-pot pyrolysis route. Taking advantage of the Ru/Ir single atoms, ultrafine RuIr nanostructure, high-porosity carbon substrate, and abundantly doped N, as well as their synergy, the as-formed composite demonstrates outstanding electrocatalytic performance for the HER under both basic and acidic conditions, with overpotentials of only 28 and 9 mV at 10 mA cm−2, respectively. Furthermore, the as-prepared RuIr@NrC exhibits robust durability for 2000 cycles. This structure outperforms its corresponding monometallic counterparts and many typical catalytic materials and is even comparable to commercial Pt/C. Notably, a high mass activity of 6.97 A mgnoble metal−1 is obtained, which is nearly ten times that of 20% Pt/C. This result shows the outstanding potential of RuIr@NrC for application in commercial water-splitting electrolyzers.