Mass-transport-limited oxidation of formic acid on a Pd ML Pt(100) electrode in perchloric acid

Abstract

In this communication, we study the electrocatalytic formic acid oxidation process on an epitaxially grown Pd monolayer on a Pt(100) single crystal in perchloric acid. The formic acid oxidation activity on this Pd ML Pt(100) electrode in perchloric acid is significantly enhanced compared to the same electrode in sulfuric acid and compared to unmodified Pt(100), with a low onset potential of around 0.14 V RHE . The absence of hysteresis between the positive and negative scan during formic acid oxidation indicates the remarkable resistance to CO poisoning of the Pd monolayer surface. Most importantly, we report, for the first time, a mass-transport-limited formic acid oxidation rate on the Pd ML Pt(100) rotating electrode in perchlorate acid, setting a catalytic benchmark for future electrocatalysts for formic acid oxidation.

How palladium inhibits CO poisoning during electrocatalytic formic acid oxidation and carbon dioxide reduction

“…We have attempted to test this model for the Pd ML Pt(100) electrode, which shows mass-transport-limited formic acid oxidation at a normal scan rate 20 . Figure S3 shows fast voltammetry results for the formic acid oxidation on Pd ML Pt(100) electrode.…”

“…However, Pd single crystals are difficult to prepare. Epitaxially grown Pd layers on a foreign metal are an interesting alternative, particularly Pt single-crystal surfaces modified by a Pd monolayer 10,11,[16][17][18][19][20] . The lattice parameters of both metals are close and it has been pointed out that the reactivity of Pd monolayer system is comparable to that of the corresponding Pd single crystal 21 .…”

Structure Sensitivity of Acetophenone Reduction on Palladium-Modified Platinum Single-Crystal Electrodes

“…The scan rate was 50 mV s –1 for both surfaces. For Pt(100), palladium deposition can also be carried out by cycling under similar conditions; however, it requires an annealing treatment using NO, which is toxic and rather avoidable. A novel method was recently exploited: underpotential deposition of palladium was carried out between 0.95 and 0.8 V in an electroplating bath containing 10 –4 M PdCl 2 , 3 × 10 –3 M HCl, and 0.1 M H 2 SO 4 at 0.1 mV·s –1 , followed by an electro-annealing process by cycling the potential between 0.4 and 0.06 at 10 mV·s –1 .…”

Tunable Periodically Ordered Mesoporosity in Palladium Membranes Enables Exceptional Enhancement of Intrinsic Electrocatalytic Activity for Formic Acid Oxidation

“…This phenomenon is expected considering the real scenario in FAO electrocatalysis systems, where the accessibility, transport efficiency and exchange kinetics of the species (e.g., HCOOH, CO 2 ) within the catalyst bulk are of vital importance for the electrocatalytic activity. [9,[16][17][18] If the majority of the pores are highly tortuous in shape and isolated from each other, resulting in sluggish mass transport, the palladium surface deep inside the pores will be shut off from fresh reagents and rapidly poisoned by product accumulation, leading to a large portion of electrocatalytically dead surfaces. [17,19,20] The issue of surface area waste could be alleviated if the mesoporosity in an electrocatalysis material is highly ordered and well interconnected, which can provide regularly oriented continuous mesochannels allowing facile diffusion of substances from the exterior region to the inner and vice versa.…”