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We report electrocatalytic decarboxylation (ECDX) of valeric acid into paraffins, olefins, and alcohols via (non-)Kolbe electrolysis on electrodes with RuO 2 and Pt nanoparticles (NPs) as a greener alternative to thermocatalytic decarboxylation. The turnover frequency of ECDX increases, while the specific activity peaks as RuO 2 NP size increases. These opposing trends make the particle size of ∼ 12 nm the optimum size for ECDX on RuO 2. Bulk Pt was active for ECDX, while Pt NPs were only active for the oxygen evolution reaction under our conditions. ECDX current efficiency remained constant in the studied potential range on RuO 2 NPs. Esterification was the favored reaction at 2.5 V vs. RHE; however, Kolbe electrolysis was the favored reaction at the expense of the esterification at 4.5 V vs. RHE. This work highlights the performance of nanostructured materials as an alternative to bulk materials as anodes for oxidative upgrading of carboxylic acids. [Display omitted] • RuO 2 nanoparticles (NPs) are a great alternative to bulk Pt for electrocatalytic decarboxylation (ECDX). • As RuO 2 NPs size increases, the turnover frequency of ECDX increases, while the specific activity reaches a maximum. • Bulk Pt is active for ECDX, while Pt NPs are only active for the oxygen evolution reaction due to surface oxidation. • Increasing potential shifts the product selectivity of ECDX from esters to paraffin production over RuO 2 NPs. [ABSTRACT FROM AUTHOR]

• Pt foil and thin films (TFs) of RuO 2 and IrO 2 are active for electrocatalytic decarboxylation (ECDX) of valeric acid at ambient conditions. • Rates of ECDX and O 2 evolution increase with potential, while the ECDX selectivity depends also on anode composition. • RuO 2 -TF is selective toward non-Kolbe products while Pt is selective toward Kolbe products. • The ECDX activity of RuO 2 -TF is similar to that of Pt foil per geometric area but is one order of magnitude more active per gram of metal. • Turnover frequencies of ECDX were at least one order of magnitude higher than thermocatalytic decarboxylation at 300 °C. The electrocatalytic upgrading of carboxylic acids, abundant biomass-derived molecules, remains a challenging task. Herein, we report an electrocatalytic decarboxylation (ECDX) approach for the conversion of carboxylic acids into paraffins, olefins, and alcohols via (non-)Kolbe electrolysis on thin films (TFs). The ECDX rate, product selectivity, and current efficiency were potential and electrode dependent. For example, the ECDX activity of RuO 2 -TF was similar to that of Pt foil, but the selectivity to Kolbe products was lower on the former. RuO 2 -TF showed about five times higher rates for the oxygen evolution reaction than Pt foil, which resulted in lower current efficiency. The ECDX and O 2 evolution activities of IrO 2 -TF were potential dependent, but this electrode was selective to non-Kolbe products with low current efficiency (<10 %). This work highlights the performance of thin films as an alternative to bulk metals as anodes for oxidative upgrading of carboxylic acids. [ABSTRACT FROM AUTHOR]