Hexanuclear ring cobalt complex for photochemical CO_(2) to CO conversion

Photosynthesis in nature has been deemed as the most significant biochemical reaction,which maintains a relatively stable content of O_(2) and CO_(2) in the atmosphere.Herein,for a deeper comprehension of natural photosynthesis,an artificial photosynthesis model reaction of photochemical CO_(2) to CO conversion(CO_(2)+2 H^(+)+2e^(-)→CO+H_(2)O)catalyzed by a homogeneous hexanuclear ring cobalt complex{K_(2)[CoO_(3)PCH_(2)N(CH_(2)CO_(2))_(2)]}_(6)(Co6 complex)is developed.Using the[Ru(bpy)_(3)]^(2+)as a photosensitizer and TEOA as a sacrificial electron donor,an optimal turnover frequency of 503.3 h^(‒1) and an apparent quantum efficiency of 0.81%are obtained.The good photocatalytic CO_(2) reduction performance is attributed to the efficient electron transfer between Co6 complex and[Ru(bpy)_(3)]^(2+),which boosts the photogenerated carriers separation of the photosensitizer.It is confirmed by the j‐V curves,light‐assisted UV‐vis curves,steady‐state photoluminescence spectra and real‐time laser flash photolysis experiments.In addition,the proposed catalytic mechanism for CO_(2) reduction reaction catalyzed by the Co6 complex is explored by the potassium thiocyanate poison experiment,Pourbaix diagram and density functional theory calculations.

Molecular confined synthesis of magnetic CoO_(x)/Co/C hybrid catalyst for photocatalytic water oxidation and CO_(2)reduction

Photosynthesis[6CO_(2)+12H_(2)O→(CH_(2)O)+6O_(2)+6H_(2)O]in nature contains a light reaction process for oxygen evolution and a dark reaction process for carbon dioxide(CO_(2))reduction to carbohydrates,which is of great significance for the survival of living matter.Therefore,for simulating photosynthesis,it is desirable to design and fabricate a bifunctional catalyst for promoting photocatalytic water oxidation and CO_(2)reduction performances.Herein,a molecular confined synthesis strategy is reasonably proposed and applied,that is the bifunctional CoO_(x)/Co/C-T(T=700,800 and 900℃)photocatalysts prepared by the pyrolysis of molecular Co-EDTA under N_(2) and air atmosphere in turn.Among the prepared photocatalysts,the CoOx/Co/C-800 shows the best photocatalytic water oxidation activity with an oxygen yield of 51.2%.In addition,for CO_(2)reduction reaction,the CO evolution rate of 12.6μmol/h and selectivity of 75%can be achieved over this catalyst.The improved photocatalytic activities are attributed to the rapid electron transfer between the photosensitizer and the catalyst,which is strongly supported by the current densityvoltage G-V,steady-state and time-resolved photoluminescence spectra(PL).Overall,this work provides a reference for the preparation and optimization of photocatalysts with the capacity for water oxidation and CO_(2)reduction reactions.