Chlorine evolution reaction electrocatalysis on RuO2(110) and IrO2(110) grown using molecular-beam epitaxy

Abstract

Chlorine evolution reaction electrocatalysis on RuO 2 (110) and IrO 2 (110) grown using molecularbeam epitaxy

Overpotential‐Dependent Volcano Plots to Assess Activity Trends in the Competing Chlorine and Oxygen Evolution Reactions

“…The descriptor analysis is based on an assessment of the CER or OER activity of RuO 2 (110) and IrO 2 (110) as both single-crystalline oxide surfaces have been widely studied by experiments. [49][50][51][52][53][54][55][56][57] In order to compile a consistent data set, the experimental measurements of Suntivich and co-workers for the CER and OER over RuO 2 (110) or IrO 2 (110) are evaluated. [52][53][54] A summary is given in Table 1.…”

“…In case of the CER, the current density at an applied electrode potential of U = 1.47 V vs. RHE in 100 mM KCl and 0.1 M H 2 SO 4 is approximately extracted from cyclic voltammetry measurements. [54] Relating to the OER, the current density at an applied electrode potential of U = 1.60 V vs. RHE (pH = 1.0) is compiled based on the analysis of experimental Tafel plots. [52,53] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 It shall be noted that an assessment of the CER vs. OER selectivity formally requires to assess activity trends at the same operational conditions, that is, at identical applied electrode potential and pH.…”

Activity‐Stability Volcano Plots for Material Optimization in Electrocatalysis

“…The free energy diagram along the reaction coordinate (cf. Figure c) provides deep mechanistic insights into electrocatalytic processes, in this case the Volmer‐Heyrovsky mechanism, which has been confirmed for the CER over RuO 2 (110) by various experimental and theoretical studies . While for small overpotentials, that is, η CER <0.125 V, the Heyrovsky step is kinetically limiting according to the highest transition state free energy, the rate‐determining reaction step switches to the Volmer step if the applied overpotential exceeds 0.125 V. Since the change in the rate‐determining reaction step was quantified in the overpotential regime between 0.10 V and 0.15 V, the affiliated error bars for the determination of the threshold overpotential (0.125 V) may not exceed 25 mV if other error sources, such as the determination of the reversible equilibrium potential, are neglected.…”

“…Figure 2c) provides deep mechanistic insights into electrocatalytic processes, in this case the Volmer-Heyrovsky mechanism, which has been confirmed for the CER over RuO 2 (110) by various experimental and theoretical studies. [18][19][20]27,46,[56][57][58][59] While for small overpotentials, that is, η CER < 0.125 V, the Heyrovsky step is kinetically limiting according to the highest transition state free energy, the rate-determining reaction step switches to the Volmer step if the applied overpotential exceeds 0.125 V. Since the change in the rate-determining reaction step was quantified in the overpotential regime between 0.10 V and 0.15 V, [57] the affiliated error bars for the determination of the threshold overpotential (0.125 V) may not exceed 25 mV if other error sources, such as the determination of the reversible equilibrium potential, are neglected. The construction of an activity-stability volcano plot enables to discuss how the performance of the RuO 2 (110) electrode material can be improved in dependence of the applied overpotential, which hitherto has been largely overlooked in the electrocatalytic literature, as outlined in the following.…”

Recent Advancements Towards Closing the Gap between Electrocatalysis and Battery Science Communities: The Computational Lithium Electrode and Activity–Stability Volcano Plots

“…From recent theoretical and experimental studies, [12,41,57,65,66,106] the reaction mechanism for the CER over RuO 2 (110) is considered to be settled. The CER proceeds through the Volmer-Heyrovsky mechanism, [107,108] in which the adsorption and discharge of ac hloride anioni nt he Volmer step [Eq.…”