The electrochemical transformation of carbon dioxide into valuable fuels represents a critical pathway for sustainable energy cycles. A principal obstacle in this field is the creation of affordable and effective electrocatalysts that combine high conversion rates with precise control over reaction products. To overcome these limitations, we have developed a composite in which copper sulfide nanoflowers are grown directly on a reduced graphene oxide (rGO) matrix via a one‐pot synthesis. Detailed material analysis indicates that the presence of rGO promotes a crystallographic shift from the covellite (CuS) structure to a metastable digenite (Cu 7.2 S 4 ) phase. Spectroscopic investigations verify substantial electron transfer at the Cu 7.2 S 4 /rGO interface, leading to a modified electronic configuration around the copper sites. In electrochemical tests, the hybrid materials display markedly improved CO 2 reduction performance. The optimized Cu 7.2 S 4 /rGO‐10 catalyst delivers a Faradaic efficiency (FE) of 82% for formate at −0.5 V versus reversible hydrogen electrode, a significant improvement over the pure CuS benchmark (64%). Furthermore, tuning the rGO loading redirects the catalytic selectivity, with the Cu 7.2 S 4 /rGO‐40 variant yielding a 75% combined FE for liquid products, predominantly ethanol. These composites also demonstrate minimal hydrogen evolution and superior long‐term stability. This work underscores the multifunctional contribution of rGO in stabilizing unconventional material phases, enhancing electrical conductivity, and directing reaction mechanisms, thereby establishing a generalizable approach for fabricating high‐performance electrocatalysts for carbon‐neutral technologies.
Khan et al. (Mon,) studied this question.