Abstract
1,3-Butadiene (C(4)H(6)), the main raw material for producing important chemicals (nylon, synthetic resin, rubber), relies on petroleum cracking with intensive carbon emissions. The electrocatalytic dimeric hydrogenation of natural gas/coal-derived C(2)H(2) to C(4)H(6) provides a nonpetroleum pathway. However, C(4)H(6), as a byproduct of C(2)H(2) hydrogenation, is usually neglected because of its very low Faradaic efficiency. Here, we theoretically and experimentally report a mechanism comprising acetylene dimerization and subsequent hydrogenation. The first dimerization process can be accelerated under appropriate coverage of acetylene and water. A ligand-modifying strategy is subsequently proposed to regulate the wettability of Cu nanoarrays to enable suitable coverages. The optimized 1-dodecanethiol-modified Cu nanoarrays deliver a 65.3% C(4)H(6) Faradaic efficiency at 100 mA cm(-2). The C(4)H(6) formation kinetics become sluggish at the two ends of the surface C(2)H(2)/H(2)O ratios, and moderate C(2)H(2)/H(2)O coverage accelerates the C‒C coupling process to promote C(4)H(6) production. Moreover, life cycle assessment demonstrates its sustainability.