Engineering ultrafine PtIr alloy nanoparticles into porous nanobowls via a reactive template-engaged assembly strategy for high-performance electrocatalytic hydrogen production

Abstract

The delicate maneuver of geometric arrangement, overall nano-architecture and chemical component of noble metal-based electrocatalysts is greatly imperative for the advancement of various industrial technologies, yet still remaining severely challenging....

Electrochemical fabrication of multi-crystalline-amorphous heterogeneous single-atom electrocatalysts for alkaline oxygen evolution reaction

“…The results state that the Tafel slopes tend to become smaller after the electrodeposition of Ir atoms, indicating that the fixation of Ir atoms on the matrix effectively improves the electron transport rate. 46 Simultaneously, the Tafel slope of CoP 2 @CN–Ir(200) is also much lower than that of CoP 2 @CN, CoP 2 @CN–Ir(100), CoP 2 @CN–Ir(300) and commercial IrO 2 (68 mV dec −1 ), indicating that CoP 2 @CN–Ir(200) has the fastest OER kinetics. 47 The variation of Tafel slopes means the shift of the rate-determining step (RDS) of the OER process, as shown by the following four reactions (* is the adsorption site).…”

“…The semicircles in the high-frequency range of the Nyquist plot indicate the charge-transfer resistance R ct , which is related to the electrocatalytic kinetics. 17,46 The Nyquist plots indicate that CoP 2 @CN–Ir(200) shows a smaller semicircle diameter ( R ct ≈ 0.9 Ω) than CoP 2 @CN (3.2 Ω), CoP 2 @CN–Ir(100) (1.7 Ω), CoP 2 @CN–Ir(300) (1.5 Ω) and IrO 2 (3.7 Ω), delivering a faster charge transfer rate. The CN matrix and the crystalline CoP 2 with good electronic conductivity, the multiple intrinsic electric fields induced by the complex heterogeneous structure, and close interactions between Ir SAs and the variant CoP 2 @CN matrix through Ir–O bonds contribute a lot to the fast charge transfer for accelerating the OER kinetics.…”