Enhancing Water Oxidation of Ru Single Atoms via Oxygen-Coordination Bonding with NiFe Layered Double Hydroxide

Abstract

Designing and synthesizing a highly active single atom catalyst, especially monodispersed noble-metal atoms fixed in two-dimensional layered double hydroxide (LDH) nanostructures, is crucial in accelerating the slow oxygen evolution reaction (OER). Here, Ru single atoms (SAs) are stabilized on NiFe LDH (SARu/NiFe LDH) via an oxygen-coordinated bond after a facile solution reduction procedure. The OER activity evaluation at similar mass loading on glassy carbon reveals that SARu/NiFe LDH shows more activity than pure NiFe LDH in basic media, possessing 99.3% of Faradaic efficiency based on rotating ring-disk electrode measurement. This is mainly due to a strong synergy between Ru SAs and NiFe LDH support. Furthermore, these supported catalysts are developed to an integrative 3D electrode in situ of the nickel foam with a higher specific surface area, which needs only an ultralow overpotential of 196 mV at 10 mA cm–2. This is one of the most efficient electrode containing monoatomic components to date. Theoretical calculations suggests that active sites of Ru can facilitate the rearrangement of electrons and optimize the binding energy both SARu/NiFe LDH catalyst and intermediates during the OER, thereby improving the intrinsic OER activity. This study provides a general avenue to developing efficiently monoatomic and even multiatomic catalysts in the future.

Ordering‐Dependent Hydrogen Evolution and Oxygen Reduction Electrocatalysis of High‐Entropy Intermetallic Pt4FeCoCuNi

“…However, the Fe2p peaks were not assignable because of their overlap with both the Co LMM Auger peak (713 eV) and Ni LMM Auger peak (713.7 eV) (Figure S18, Supporting Information). [ 54,71–74 ]…”

“…However, the Fe2p peaks were not assignable because of their overlap with both the Co LMM Auger peak (713 eV) and Ni LMM Auger peak (713.7 eV) (Figure S18, Supporting Information). [54,[71][72][73][74] The surface area and pore distribution of carbon matrix encapsulating nanoparticles were investigated using Brunauer-Emmett-Teller (BET) analysis (Figure S19 and Table S4, Supporting Information). The sulfur-carbon matrix has a large surface of 690.8 m 2 g −1 and abundant mesopores (pore volume: 0.85 cm 3 g −1 ) with an average pore size of 58.2 Å.…”

Atomic Modulation of Single Dispersed Ir Species on Self-Supported NiFe Layered Double Hydroxides for Efficient Electrocatalytic Overall Water Splitting

“…For OER, we used the conventical absorbate evolution mechanism to simulate the oxygen evolution process, which has been widely regarded as the main mechanism for NiFe-LDH. , The most possible adsorption site of Ir SAC -NiFe-LDH was calculated to be the Ni site that neighbored Ir with the lowest adsorption energy of −1.367 eV (Table S11), and the optimal adsorption site of NiIr SAA -NiFe-LDH was the Ni of the NiIr SAA that is adjacent to Ir (−1.658 eV, Table S12). Therefore, the OER processes were favored to be conducted at the Ni site for both Ir SAC -NiFe-LDH and NiIr SAA -NiFe-LDH, where the *OH intermediates were first adsorbed and then evolved sequentially to *O, *OOH, and O 2 (Figures S17 and S18).…”

Unveiling the Oxygen Evolution Mechanism with FeNi (Hydr)oxide under Neutral Conditions

“…OER is a bottleneck and results in a surplus of cell voltage. Ir , and Ru , compounds are effective OER catalysts but are too scarce and precious to be used on a large scale.…”