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

Abstract

A new hybrid of the nanostructured RuIr alloys on highly porous and N-rich carbon skeleton (RuIr@NrC), prepared by a facile one-pot pyrolysis route, performs well for the hydrogen evolution reaction in both alkaline and acidic electrolytes, which is comparable to and even exceeds that of documented representative electrocatalysts, including the benchmark Pt/C. • The RuIr@NrC is prepared by a simple and scalable one-pot pyrolysis method. • RuIr@NrC with RuIr alloys (~3.87 nm) on highly porous and N-rich carbon matrix. • RuIr@NrC showed high HER catalytic activity and stability. • A high mass activity is attainable, largely outperforming that of Pt/C. • The structural advantages and component synergy cause the high activity. The production of green energy, in this case, hydrogen (H 2 ), 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 mg noble 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.