Understanding the interplay between electrocatalytic C(sp3)‒C(sp3) fragmentation and oxygenation reactions

Abstract

Achieving the selective electrocatalytic activation of C(sp3)–C(sp3) and C(sp3)−H bonds is key to enabling the electricity-driven synthesis of chemicals, the sustainable upgrading of plastics and the development of fuel cells operating on energy-dense liquid fuels. When exposed to electrodes under oxidative bias, hydrocarbons undergo both C–C bond fragmentation and oxygenation. Currently, we lack control over the bifurcation of these pathways. Here we provide insights into the complex network of alkyl transformation reactions, showing that under oxidizing potentials, adsorbed butane transforms to adsorbed CHx fragments, which can be desorbed as methane before oxidation to adsorbed CO. Identifying the branchpoint between C‒C fragmentation and oxygenation allowed us to steer selectivity by applying pulsed potentials tailored to the desorption potential of specific adsorbates and the kinetics of intermediate oxidation. Our findings provide design criteria for improved fuel cell catalysts and open the door to selective C‒C cleavage in electrosynthetic pathways. The electrochemical activation of alkanes on metal catalysts is a complex process that is not fully understood. Now an electrochemical protocol is put forward to isolate the adsorption, fragmentation and oxygenation potential-dependent steps of butane activation on a platinum electrode and derive its intricate reaction network.