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 CH_x 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.

实现C( sp ³ )–C( sp ³ )和C( sp ³ )−H键的选择性电催化活化是实现电驱动化学品合成、塑料可持续升级和燃料电池发展的关键能源密集型液体燃料。当在氧化偏压下暴露于电极时，碳氢化合物会发生 C-C 键断裂和氧化。目前，我们缺乏对这些途径的分叉的控制。在这里，我们深入了解了烷基转化反应的复杂网络，表明在氧化电位下，吸附的丁烷转化为吸附的 CH _x碎片，这些碎片可以在氧化为吸附的 CO 之前解吸为甲烷。识别 C-C 碎片和氧化之间的分支点使我们能够通过应用根据特定吸附物的解吸电位和中间氧化动力学定制的脉冲电位来控制选择性。我们的研究结果为改进燃料电池催化剂提供了设计标准，并为电合成途径中选择性 C-C 裂解打开了大门。