NiO as a Bifunctional Promoter for RuO₂ toward Superior Overall Water Splitting

Abstract

Conventional development of nanomaterials for efficient electrocatalysis is largely based on performance-oriented trial-and-error/iterative approaches, while a rational design approach at the atomic/molecular level is yet to be found. Here, inspired by a fundamental understanding of the mechanism for both oxygen and hydrogen evolution half reactions (OER/HER), a unique strategy is presented to engineer RuO for superior alkaline water electrolysis through coupling with NiO as an efficient bifunctional promoter. Benefitting from desired potential-induced interfacial synergies, NiO-derived NiOOH improves the oxygen binding energy of RuO for enhanced OER, and NiO also promotes water dissociation for enhanced HER on RuO -derived Ru. The resulting hybrid material exhibits remarkable bifunctional activities, affording 2.6 times higher OER activity than that of RuO and an HER activity comparable to Pt/C. As a result, the simple system requires only 1.5 V to deliver 10 mA cm for overall alkaline water splitting, outperforming the benchmark PtC/NF||IrO /NF couple with high mass loading. Comprehensive electrochemical investigation reveals the unique and critical role of NiO on the optimized RuO /NiO interface for synergistically enhanced activities, which may be extended to broader (electro)catalytic systems.

Hollow Multivoid Nanocuboids Derived from Ternary Ni–Co–Fe Prussian Blue Analog for Dual‐Electrocatalysis of Oxygen and Hydrogen Evolution Reactions

“…Rapidly increasing international development of renewable and green energy sources has drawn widespread attention of researchers to water‐splitting oxygen and hydrogen production via the electrochemical oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively . To enhance these reactions to commercially viable rates, however, high‐performance electrocatalysts are required to overcome the activation energies associated with OER and HER .…”

Channel‐Rich RuCu Nanosheets for pH‐Universal Overall Water Splitting Electrocatalysis

“…[11][12][13][14] Ruthenium, owing to the advantages of the cheapest among platinum group metals and excellent performance in many applications such as N 2 electrochemical reduction and selective hydrogenation, has attracted much attention. [17][18][19][20] Forinstance, Su and co-workers have obtained Cu-doped RuO 2 hollow porous polyhedra through one-step annealing of Ru-exchanged Cu-BTC derivatives,w hich showed remarkable OER performance in 0.5 m H 2 SO 4 . [17][18][19][20] Forinstance, Su and co-workers have obtained Cu-doped RuO 2 hollow porous polyhedra through one-step annealing of Ru-exchanged Cu-BTC derivatives,w hich showed remarkable OER performance in 0.5 m H 2 SO 4 .…”

“…[15,16] Significantly,i th as also been shown that Ru-based electrocatalysts are active in both HER and OER. [17][18][19][20] Forinstance, Su and co-workers have obtained Cu-doped RuO 2 hollow porous polyhedra through one-step annealing of Ru-exchanged Cu-BTC derivatives,w hich showed remarkable OER performance in 0.5 m H 2 SO 4 . [21] Liu and colleagues have synthesized multi-heterogeneous Ni@Ni 2 P-Ru nanorods showing excellent electrocatalytic HER performance.…”

Double Perovskite LaFexNi1−xO3 Nanorods Enable Efficient Oxygen Evolution Electrocatalysis

“…As the energy crisis becomes more and more prominent because of the rapidly growing energy demand, the design of efficient and cost‐effective catalysts for electrochemical energy conversions to meet the high demands of renewable energies becomes highly urgent . The oxygen evolution reaction (OER, 4 OH − → 2 H 2 O + O 2 + 4 e − in base) is the vital step for many renewable‐energy technologies . However, the kinetics of OER is sluggish due to the multistep proton‐coupled electron transfer, which requires large overpotential to reach desirable current density .…”