Engineering Ir Atomic Configuration for Switching the Pathway of Formic Acid Electrooxidation Reaction

Abstract

Switching the formic acid oxidation reaction (FAOR) pathway from CO intermediate to direct CO 2 formation is essential for noble-metal electrocatalysts, but rare investigations on Ir-based materials. Herein, the atomic configurations of Ir are controlled to enhance the FAOR performance via Ir 3 V intermetallics (O-Ir 3 V). As the ordering degree of O-Ir 3 V increases, the Ir ensemble size decreases to trimer and dimer, leading to a 7.3 times promotion in mass normalized activity relative to Ir. Supported by electrochemical in situ attenuated total reflection infrared spectroscopy results, it shows that FAOR occurs via linear CO mediated pathway on Ir, but it is totally switched to a direct pathway on highly ordered O-Ir 3 V. The preserved ordered structure and V oxides on the surface during the durability test contribute to the enhanced stability. This study provides an idea to switch the FAOR pathway through tuning the Ir atom configuration by constructing ordered intermetallics.

Synergistic effect of PtNi alloy loading on TiB2 to construct SMSI catalysing formic acid dehydrogenation

“…The ordered alloys provide possibilities to ne-tune the structural conguration of noble metals by controlling stoichiometric ratios and long-range orderliness. 25 To further understand the physicochemical properties of the supported bimetallic catalysts, it is important to probe the distribution and chemical state of metals within each individual nanoparticle. The average metal particle size and dispersion of Pt 3 Ni 8 on TiB 2 were observed by HR-TEM (Fig.…”

“…The ordered alloys provide possibilities to fine-tune the structural configuration of noble metals by controlling stoichiometric ratios and long-range orderliness. 25…”

Recent Advances in Anode Electrocatalysts for Direct Formic Acid Fuel Cells – Part I – Fundamentals and Pd Based Catalysts

“…Therefore, with the long-range ordering degree increasing, and reduced the proportion of Ir atom in larger ensembles, the activity for FAO increase (Figure 9E). [240] Antimony is used to improve the stability of the electrocatalysts. studied the effect of addition of Sb on the deactivation of the Pd/C catalysts.…”

“…Figure 9. (A) Geometric area normalized CV curves for the catalysts in N 2 saturated 0/5 M H 2 SO 4 at a scan rate 50 mVs À 1 Noble metal mass normalized LSV curves(B) and geometric area normalized CVs (C) for the catalysts in N 2 saturated 0.5 M H 2 SO 4 + 0.5 M HCOOH at at a scan rate 50 mV s À 1 (D) Schematic diagram of (111) plane of Ir, partially ordered Ir 3 V and totally ordered Ir 3 V with different Ir atom ensembles[240] (Reproduced with permission from reference 240, John Wiley and Sons, 2022)…”

Recent Advances of Single‐Atom‐Alloy for Energy Electrocatalysis

“…[ 4 ] For example, core–shell structured Pt 3 Co@Pt, [ 5 ] PtFe@Pt, [ 6 ] and PtNi@Pt [ 7 ] nanoparticles have displayed enhanced electrocatalytic activity toward oxygen reduction reaction (ORR) compared with pure Pt nanoparticles. In another example, intermetallics featuring smaller Pt [ , 8 ] Pd, [ 9 ] and Ir [ 10 ] atomic ensembles displayed higher formic acid oxidation reaction (FAOR) activity compared with corresponding monometallic nanoparticles. Thus, alloying is a feasible strategy to promote electrocatalytic performances.…”