A Hybrid Co Quaterpyridine Complex/Carbon Nanotube Catalytic Material for CO2 Reduction in Water

Abstract Associating a metal‐based catalyst to a carbon‐based nanomaterial is a promising approach for the production of solar fuels from CO 2 . Upon appending a Co II quaterpyridine complex Co(qpy) 2+ at the surface of multi‐walled carbon nanotubes, CO 2 conversion into CO was realized in water at pH 7.3 with 100 % catalytic selectivity and 100 % Faradaic efficiency, at low catalyst loading and reduced overpotential. A current density of 0.94 mA cm −2 was reached at −0.35 V vs. RHE (240 mV overpotential), and 9.3 mA cm −2 could be sustained for hours at only 340 mV overpotential with excellent catalyst stability (89 095 catalytic cycles in 4.5 h), while 19.9 mA cm −2 was met at 440 mV overpotential. Such a hybrid material combines the high selectivity of a homogeneous molecular catalyst to the robustness of a heterogeneous material. Catalytic performances compare well with those of noble‐metal‐based nano‐electrocatalysts and atomically dispersed metal atoms in carbon matrices.