Construction of Ordered Atomic Donor–Acceptor Architectures in bcc IrGa Intermetallic Compounds toward Highly Electroactive and Stable Overall Water Splitting

Abstract

Benefiting from ordered atomic structures and strong d‐orbital interactions, intermetallic compounds (IMCs) are promising electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, the body‐centered cubic IrGa IMCs with atomic donor–acceptor architectures are synthesized and anchored on the nitrogen‐doped reduced graphene oxide (i.e., IrGa/N‐rGO). Structural characterizations and theoretical calculations reveal that the electron‐rich Ir sites are atomically dispersed in IrGa/N‐rGO, facilitating the electron transfer between Ir atoms and adsorbed species, which can efficiently decrease the energy barriers of the potential determining step for both HER and OER. Impressively, the IrGa/N‐rGO||IrGa/N‐rGO exhibits excellent performance for overall water splitting in alkaline medium, requiring a low cell voltage of 1.51 V to achieve 10 mA cm−2, meanwhile, exhibiting no significant degradation for 100 h. This work demonstrates that the rational design of noble metal electrocatalysts with donor–acceptor architectures is beneficial for catalytic reactions in energy conversion applications.

Recent progress in intermetallic nanocrystals for electrocatalysis: From binary to ternary to high‐entropy intermetallics

“…The enhanced HER kinetics was ascribed to the charge redistribution on the ordered Ir 3 V surface with a maximized number of neighboring Ir/V sites compared to the disordered counterpart, thereby promoting water dissociation on the electron‐deficient V sites. bcc intermetallic IrGa nanoparticles on N‐doped rGO exhibited excellent performance toward both HER and OER, thus having a low cell voltage of 1.51 V to achieve 10 mA/cm 2 for the overall water splitting in alkaline condition 61 . DFT calculations suggested that the high performance could be ascribed to the creation of electron‐rich Ir via incorporating Ga with lower electronegativity, such that the electron transfer between Ir and the adsorbed species could be promoted, thereby decreasing the energy barriers of the potential determining steps.…”

“…High-surface-area substrates can enlarge the interparticle distance and provide a support for the migration and diffusion of metal atoms, such that particle aggregation can be mitigated to some extent during annealing. Various two-dimensional (2D) substrates have been used for this purpose, such as carbon black, 54,59 GO, 56,60,61 and metal oxides. 62 The annealing temperature and period are determinant parameters for manipulating the degree of ordering of intermetallic nanocrystals.…”

Laves phase Ir2Sm intermetallic nanoparticles as a highly active electrocatalyst for acidic oxygen evolution reaction

“…[20][21][22][23][24] Theoretically, constructing an intermetallic with an ordered atomic arrangement can enhance the electrocatalytic activity and durability, and reduce the use of noble metals. 25,26 Alloys modify the electronic state of catalytically active elements through electronic effects, and the degree of modication depends largely on the nature and composition of the second metal. 27 RE elements have a unique electronic structure of [Xe]4f n-1 5d 0-1 6s 2 (n = 1-15), which can provide an additional route for adjusting the electronic structure of catalytically active elements.…”

Atomically dispersed ruthenium sites with electron-rich environments in intermetallic compounds for high-current-density hydrogen evolution

“…[18][19][20][21] To enhance the HER performance and decrease the consumption of Ru, the fabrication of composition-dened and atomic ordered Ru-based intermetallic compounds (IMCs) is a promising strategy. [22][23][24][25][26] The insertion of a relatively lower electronegative metal (i.e., Ga) could create electron-rich environments for the Ru atoms, [27][28][29][30] which can modulate the electronic structure of Ru sites and improve the HER performance. In addition, the higher mixing enthalpy and stronger interactions between Ru and Ga atoms can rmly stabilize Ru atoms during the electrochemical measurements in both acidic and alkaline electrolytes.…”

“…22–26 The insertion of a relatively lower electronegative metal ( i.e. , Ga) could create electron-rich environments for the Ru atoms, 27–30 which can modulate the electronic structure of Ru sites and improve the HER performance. In addition, the higher mixing enthalpy and stronger interactions between Ru and Ga atoms can firmly stabilize Ru atoms during the electrochemical measurements in both acidic and alkaline electrolytes.…”