Synergistic effect of iron phthalocyanine and ultrafine cobalt nanoparticles for efficient CO2 electroreduction to syngas

Abstract

Developing efficient electrocatalysts for CO2 electroreduction to syngas with a specific H2/CO ratio over a wide potential window is desperately required but still challenging. In this work, a series of dual-site catalysts composed of iron phthalocyanine (FePc) and ∼18 nm Cobalt nanoparticles (Co NPs) anchored on N-doped carbon matrix has been constructed from zeolitic imidazolate framework-67 (ZIF-67). Benefiting from the synergistic effect of FePc and Co NPs, the derived FePc/Co@N–C catalyst shows impressive capability for CO2 electrolysis to syngas. By varying the pyrolysis temperatures (600–800 °C) of ZIF-67 and the mass ratio of Co@N–C to FePc (1–3), an adjustable H2/CO ratio of 2–4 is obtained, and the value can be maintained stable within a potential window of −0.66 to −0.86 V vs. RHE in an H-type cell. Moreover, this electrocatalyst exhibits favorable stability without distinct performance decay. When conducted in a flow cell, an enhanced catalytic activity is demonstrated with an industrial current density (>100 mA cm−2) at −0.8 V vs. RHE and a steady H2/CO ratio of 2 from −0.4 to −0.6 V vs. RHE. This work provides a promising strategy of designing bifunctional electrocatalysts for syngas generation with stable H2/CO ratio across a wide potential range.