Phosphidation of Cu²⁺ Ions Loaded HKUST-1 to Derive Cu₃P/C Nanomaterials for Electrocatalytic Carbon Dioxide Reduction

Developing effective electrocatalysts for the conversion of CO 2 to CO is essential for enhancing the global carbon cycle. In this article, we report the synthesis of Cu 3 P/C nanomaterials, derived from the copper-based MOF (HKUST-1), using a novel phosphidation method. To enhance the copper contents in the final material, HKUST-1 is impregnated in Cu 2+ solutions of various concentrations, followed by phosphidation. Cu 3 P nanoparticles fully embedded in hierarchical carbon have been confirmed by using transmission electron microscopy. These nanoparticles exhibit remarkable efficiency in the reduction of CO 2 to CO. Among the various synthesized electrocatalysts, the optimal electrocatalyst, i.e., (5 M) Cu 3 P/C demonstrates outstanding performance, which shows 88% Faradaic efficiency for CO production. It also demonstrates a low overpotential (η) of only 177 mV, a high current density (j) of 60 mA cm –2, and long-term stability over 20 h at various potentials in 0.1 M KHCO 3 medium, making it an excellent choice for CO 2 reduction applications. The catalyst’s exceptional selectivity for converting CO 2 to CO is further validated by qualitative detection of CO using the PdCl 2 strips method.