Scalable Solid‐State Synthesis of Highly Dispersed Uncapped Metal (Rh, Ru, Ir) Nanoparticles for Efficient Hydrogen Evolution

Abstract

Green and scalable syntheses of highly dispersed supported metal nanocatalysts (SMNCs) are of significant importance for heterogeneous catalysis in industry. In order to achieve nanosized SMNCs and prevent metal nanoparticles (NPs) from aggregation, the traditional liquid syntheses commonly require organic capping agents and low metal loading, which are unfavorable for practical production of SMNCs. Herein, a green and facile solid‐state approach is reported for a general synthesis of Rh, Ru, and Ir NPs highly dispersed on different carbon supports via a room‐temperature mortar grinding. The synthesis is easy to scale up and no organic solvent is needed. Metal NPs are free of capping agents and in a couple of nanometers with a uniform size distribution. Benefiting from the above features and high intrinsic activity, Rh NP/C shows the superior activity for hydrogen evolution reaction (HER) in terms of an ultralow overpotential of 7 mV at 10 mA cm−2, outperforming the state‐of‐the‐art HER electrocatalysts. The cell voltage to output a stable current density of 10 mA cm−2 is only 1.53 V for the electrolyzer with Rh NP/C cathode. These results indicate that the present scalable solid‐state synthetic strategy paves a new avenue for mass production of highly efficient SMNCs for diverse applications.

Ruthenium Nanoparticles for Catalytic Water Splitting

“…In terms of scalable and cost‐effective methods for the production of active Ru‐based NP systems for the HER, Hu and co‐workers recently reported the solid‐state synthesis of Ru NPs . These NPs were simply prepared by mixing RuCl 3 , NaOH, NaBH 4 , and a C source in an agate mortar at room temperature.…”

“…In terms of scalablea nd cost-effective methods for the productiono fa ctiveRu-based NP systemsf or the HER, Hu and coworkers recently reported the solid-state synthesis of Ru NPs. [76] These NPs weres imply prepared by mixing RuCl 3 , NaOH, NaBH 4 ,a nd aCsource in an agate mortar at room temperature. Thisl ed to very active, stable, and homogeneous in size (1.7 nm) Ru NPs deposited onto C( Ru/C)w ith values of h 10 = 24 mV and b = 33 mV dec À1 at pH 14 (Table 4, entry 27); thus improving again on the performance of commercial Pt/C in alkaline solution.…”

Mechanochemically Assisted Synthesis of Ruthenium Clusters Embedded in Mesoporous Carbon for an Efficient Hydrogen Evolution Reaction

“…Figure a displayed linear sweep voltammetry (LSV) curves of electrocatalysts at a sweep rate of 5 mV s −1 with iR correction. Remarkably, Ru‐CN/MC presented an extremely low HER overpotential of 17 mV at a current density of 10 mA cm −2 in 1 M KOH, which was obviously outperformed benchmark Pt/C (31 mV@10 mA cm −2 ) and many previously reported Ru‐based HER electrocatalysts such as Ru@N‐doped graphite carbon (29 mV@10 mA cm −2 ), Ru nanoparticles on carbon support (Ru NP/C, 25 mV@10 mA cm −2 ), RuP 2 nanoparticles encapsulated in a N,P dual‐doped carbon framework (RuP 2 @NPC, 52 mV@10 mA cm −2 ) and Ru‐doped NiFe‐layered double hydroxide nanosheets (NiFeRu‐LDH, 29 mV@10 mA cm −2 ) . A detailed comparison of various HER electrocatalysts is shown in Table S3 in the Supporting Information, further confirming the remarkable catalytic performance of Ru‐CN/MC.…”

Synthesis and Cytotoxicity Studies on Ru and Rh Nanoparticles as Potential X-Ray Fluorescence Computed Tomography (XFCT) Contrast Agents

“…From the TEM micrographs, Ru-2 was observed to have an average particle size of 2.5 nm while Rh-4 has 8.7 nm. The observed difference in the size of Ru and Rh NPs prepared under the same conditions is related to their standard reduction potential, where a higher reduction potential corresponds to a larger particle size [22]. The difference in size between Ru and Rh series, therefore, can be ascribed to the lower reduction potential of Ru 3+ (0.60 mV), as compared to that of Rh 3+ (0.76 mV).…”