Electrocatalytic reactions play a central role in replacing a fossil fuel-based economy with systems based on renewable energy that provide green electricity and produce basic chemicals and fuels. Electrochemical splitting of water, for example, produces hydrogen at the cathode, which can be used as an energy carrier, fuel, or as a chemical in refining processes. Nevertheless, the slow kinetics of the oxygen evolution reaction (OER) at the anode and the need for scarce and expensive platinum group metals as highly active electrocatalyst materials hinder efficient water electrolysis on an industrially relevant scale. Therefore, the substitution of OER by the electrochemical alcohol oxidation reaction (AOR) using non-noble metal electrocatalysts could decrease the electrical energy and cost needed to produce hydrogen at the cathode, while also producing value-added chemicals at the anode.^[1-4] In particular, the electrooxidation of glycerol, a waste product of the biodiesel industry, is highly interesting since multiple products, all required in different industries, can be obtained.^[5] Still, controlling the reaction selectivity becomes a challenge. Suppressing the cleavage of the C-C bond over non-noble metal-based electrocatalysts is challenging. Often, only formate is reported as a major product, while C2 (e.g., oxalic acid) or C3 (e.g., glyceric acid) products are obtained in lower amounts.

In this communication, the electrocatalytic performance of several multi-metal-based catalysts based on Co, Cu, or Ni in the alcohol electrooxidation will be discussed. The first part of the talk will focus on understanding how tuning the Co:Cu ratio in a CoCu hydroxycarbonate impacts the activity and selectivity of different alcohols. In the presence of glycerol, in-situ leaching of Cu is observed, which leads to activation of the electrocatalyst. While the activity can be tuned, the selectivity remains unchanged, with formate being the only product.^[6]  Therefore, to suppress the C-C cleavage and increase the formation of C3 products, solketal, a mono alcohol obtained by acetal modification of glycerol, is electro-oxidized instead of glycerol.^[7] Using solketal, the stability of the Cu-based catalyst during the electrooxidation reaction is also modified. In the second part, ATR-IR spectroscopy and single-particle-on-the-nanoelectrode with identical-location transmission electron microscope provide additional insights into how the presence of solketal impacts the catalyst reconstruction and product formation, explaining the impact of Cu leaching on the GOR and SOR activity, in a CoNiFeCu multimetal electrocatalysts.