Resonance-Promoted Formic Acid Oxidation via Dynamic Electrocatalytic Modulation

Abstract

It is a truth universally acknowledged that faster catalysts enable more efficient transformation of molecules to useful products and enhance the utilization of natural resources. However, the limit of static catalyst performance defined by the Sabatier principle has motivated a dynamic approach to catalyst design, whereby catalysts oscillate between varying energetic states. In this work, the concept of dynamic catalytic resonance was experimentally demonstrated via the electrocatalytic oxidation of formic acid over Pt. Oscillation of the electrodynamic potential between 0 and 0.8 V NHE via a square waveform at varying frequency (10 −3 < f < 10 3 Hz) increased the turnover frequency to ∼20 s −1 at 100 Hz, over one order of magnitude (20×) faster than optimal potentiostatic conditions. We attribute the accelerated dynamic catalysis to nonfaradaic formic acid dehydration to surface-bound carbon monoxide at low potentials, followed by surface oxidation and desorption to carbon dioxide at high potentials.

The Catalytic Mechanics of Dynamic Surfaces: Stimulating Methods for Promoting Catalytic Resonance

“…(275) Other adsorbates such as CO, O, and OOH will be more sensitive to induced electric fields based on calculations for Pt(111); (276) this means that CATFETs show promise for a broad range of chemistries including the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), CO oxidation, formic acid oxidation or decomposition, and methanol oxidation or decomposition. (50,(277)(278)(279) 3.8 Dynamic Ferroelectrics. Ferroelectrics, such as niobates, titanates, and zirconates (for example, BaTiO 3 , PbTiO 3 , SrTiO 3 and LiNbO 3 ), are materials that have a macroscopic polarization (electric dipole moment per unit volume) that can be switched by an applied electric field.…”

“…Development of linear scaling relationships that characterize the nature of stimuli are direct methods for making comparisons, (52,276,311) and microkinetic modeling (MKM) based on these relationships across different potential dynamic catalyst technologies will ultimately be the tool to predict new catalysts. (50,52) Examples of the opportunity provided by different stimuli can already be found in the application of strain and electric fields to transition metals. As shown in Figure 17a, comparison of the periodic trends for the adsorption of NH 2 * and NH* with the application of electric fields on Pt (111) surface both indicate positive scaling of NH2 * /NH * of 0.49 and 1.37, respectively.…”

“…As an example, an electrocatalysis system oscillating between 0 V and 0.6 V should compare the dynamic apparent turnover frequency with the steady state electrocatalytic rate at both 0 V and 0.6 V. This is demonstrated in Figure 12c, when a volcano versus applied voltage is observed for formic acid electro-oxidation on Pt with dynamic rates observed above all fixed-voltage conditions. (50) To claim oscillatory rate enhancement, the observed time-averaged dynamic production rate needs to exceed the steady state rates obtained at either operating endpoint. Finally, we urge caution in interpreting apparent activation energies (E a,app ) under dynamic catalytic conditions.…”

“…The paradigm of a dynamic catalysis changes the philosophy for catalyst synthesis and discovery and the strategy for utilizing a new temporal dimension for catalyst design. It has already been experimentally demonstrated that oscillating catalysts break the limits of static catalysts in the rate acceleration of electro-oxidation of formic acid (50) . But it is also possible that dynamic catalysts can change the mechanism for selecting individual reactions in a network (51) , while also altering catalyst operation in equilibrium-controlled reactions (52) .…”

Structure–Reactivity Effects of Biomass‐based Hydroxyacids for Sustainable Electrochemical Hydrogen Production

“…This Pd oxide layer can be removed by electrochemical reduction inducing the regeneration of the catalyst surface (Pd active sites) recovering the initial response for LA oxidation. This surface reactivation process has been previously exploited to increase the reaction rate and stability of Pd‐based catalysts for LA oxidation [32] and other reactions [67] . Galvanostatic curves were recorded at higher current densities (75–200 mA cm −2 ) to study the time‐dependent GA oxidation which also took place at very low potentials (Figure 6b) and significantly lower than those obtained for the LA oxidation.…”