Thiol-directed synthesis of high-loading Ag nanoparticles on carbon for efficient and stable CO2 electroreduction

Transitioning to a net-zero society requires efficient electrochemical technologies for converting carbon dioxide (CO 2 ) into valuable products powered by renewable energy. The commercial deployment of CO 2 electrolyzers requires catalysts that combine high activity, selectivity, and scalability. This study reports a novel and facile synthesis strategy for highly loaded, uniformly dispersed silver nanoparticles (AgNPs) on conductive carbon substrates using 1-dodecanethiol as a stabilizing ligand. This approach enables simultaneous control over particle size (<7 nm) and metal loading (up to 60 wt %) on Vulcan XC (low surface area) and Ketjen Black (high surface area). Using 1-dodecanethiol effectively prevents agglomeration, yielding highly dispersed AgNPs even at ultrahigh loading. We present a systematic investigation into the influence of carbon support surface area on Ag dispersion, loading efficiency, and electrocatalytic performance. Notably, Ag/KB-60 exhibits a faradaic efficiency of 90 % for CO at −0.81 V vs. RHE and remarkable operational stability over 24 h. This work presents a low-cost, thiol-based synthesis strategy that is readily scalable for industrial manufacturing of CO 2 electrolyzers, enabling the production of high-performance Ag/C catalysts with commercial relevance.