Exclusive Strain Effect Boosts Overall Water Splitting in PdCu/Ir Core/Shell Nanocrystals

Abstract

Core/shell nanocatalysts are ac lass of promising materials,w hicha chieve the enhanced catalytic activities through the synergy between ligand effect and strain effect. However,i th as been challenging to disentangle the contributions from the two effects,whichhinders the rational design of superior core/shell nanocatalysts.H erein, we report precise synthesis of PdCu/Ir core/shell nanocrystals,w hichc an significantly boost oxygen evolution reaction (OER) via the exclusive strain effect. The heteroepitaxial coating of four Ir atomic layers onto PdCu nanoparticle gives arelatively thickIr shell eliminating the ligand effect, but creates ac ompressive strain of ca. 3.60%. The strained PdCu/Ir catalysts can deliver al ow OER overpotential and ah igh mass activity.D ensity functional theory (DFT) calculations reveal that the compressive strain in Ir shell downshifts the d-band center and weakens the binding of the intermediates,c ausing the enhanced OER activity.The compressive strain also boosts hydrogen evolution reaction (HER) activity and the strained nanocrystals can be served as excellent catalysts for both anode and cathode in overall water-splitting electrocatalysis.

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

“…S3 †). 23,[41][42][43][44][45] As shown in Fig. 4b, the intermetallic Ir 2 Sm NPs exhibit lower Tafel slopes (72.9 mV dec −1 for Ir 2 Sm-S/G and 81.3 mV dec −1 for Ir 2 Sm-L/G), indicating that the Sm element effectively modulates the reaction kinetics of Ir in the acidic OER.…”

“…Compared with other Ir-based alloy materials, including Ir-Cu, Ir-Ni, and Ir-Rh, Ir 2 Sm-S/G could work at much lower overpotentials (Table S3†). 23,41–45 As shown in Fig. 4b, the intermetallic Ir 2 Sm NPs exhibit lower Tafel slopes (72.9 mV dec −1 for Ir 2 Sm-S/G and 81.3 mV dec −1 for Ir 2 Sm-L/G), indicating that the Sm element effectively modulates the reaction kinetics of Ir in the acidic OER.…”

“…It can be observed that the overpotentials at a current density of 10 mA cm −2 are 275 mV (Ir 2 Sm-S/G) and 310 mV (Ir 2 Sm-L/G), which are much lower than those for Ir/G (389 mV) and Ir/C (379 mV), respectively, indicating that the alloying of Sm and Ir effectively enhances the OER activity in acidic medium. Compared with other Ir-based alloy materials, including Ir-Cu, Ir-Ni, and Ir-Rh, Ir 2 Sm-S/G could work at much lower overpotentials (TableS3†) 23,[41][42][43][44][45]. As shown in Fig.4b, the intermetallic Ir 2 Sm NPs exhibit lower Tafel slopes (72.9 mV dec −1 for Ir 2 Sm-S/G and 81.3 mV dec −1 for Ir 2 Sm-L/G), indicating that the Sm element effectively modulates the reaction kinetics of Ir in the acidic OER.The double-layer capacitance (C dl ) of the catalysts derived from the cyclic voltammetry (CV) curves (ESI, Fig.S8 †) was used to calculate the electrochemically active surface area (ECSA) [46][47][48][49].…”

Ultrasmall PdCuMo Nanoparticle Assemblies for Hydrogen Evolution

“…Such a strong peak shift suggests that the surface electronic state of PdCuMo assemblies has changed, and the electron transfer occurs in the Pd-d band, which originates from the atomic rearrangement due to the introduction of Cu and Mo. As a result, the adsorption of reaction intermediates on the surface of amorphous-dominated PdCuMo assemblies is weakened, leading to an enhanced HER performance . The charge transfer can also be corroborated by electrochemical impedance spectroscopy (EIS) tests, and the correlation results are presented in the form of Nyquist plots (Figure D).…”

Ir–Ru Electrocatalysts Embedded in N‐Doped Carbon Matrix for Proton Exchange Membrane Water Electrolysis

“…f) Amounts of Ir and Ru dissolved during two degradation tests. g) Potential-time profiles of Ir 75 Ru 25 @CM and Ir 88 Ru 12 @CM at 10 mA cm −2 for 120 h. h) Summary of OER overpotential at 10 mA cm −2 for previously reported Ir-based electrocatalysts [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] and Ir 88 Ru 12 @CM.…”