A cyanide-bridged di-manganese complex, {[Mn(bpy)(CO)3]2(μ-CN)}+, is introduced as an efficient electrocatalyst and photochemically active for proton-assisted of CO2 reduction to CO.

Certain alloys of nickel have recently been shown to reduce CO 2 to multi-carbon products electrochemically without the need for copper. Here we show that Ni 3 Ga thin film electrocatalysts on carbon electrodes discriminate between CO 2 reduction pathways and products based on their surface morphologies, which are controlled by catalyst-carbon support interactions. It is also observed that unsupported, bulk Ni 3 Ga reduces CO but not CO 2 . With this understanding, a tandem electrocatalyst utilizing two variants of the Ni 3 Ga material-one supported and one unsupported-was developed. In this two-electrode system, CO is generated from CO 2 on an electrode optimized for this process, and the CO is then further reduced to methanol in the same reactor. It appears that choice of carbon support impacts the morphology of Ni 3 Ga during the synthesis of the catalyst, thereby influencing the electrolysis product distribution. The discovery or design of CO 2 reduction catalysts has been a focus of current electrochemical studies due to the rising concentration of CO 2 in the atmosphere coupled with global challenges accompanying such a phenomenon.1,2 Materials that facilitate the transformation of CO 2 are wide-ranging, but a deficiency in our understanding of how they function is exemplified by several recent studies reporting on what is nominally the same electrode material after modifying the structure, morphology, or composition and eliciting a new or improved response toward CO 2 reduction. 3-10When a known CO 2 -reducing material is altered to include novel structures or morphologies, it is anticipated that the newly introduced characteristic may change the base material's activity by increasing the concentration of surface active sites or improving intermediate stability, thereby impacting catalysis. As an example, the Kanan group has reported that copper catalyst morphology influences the distribution and faradaic efficiencies of CO 2 reduction products. 11 The importance of morphology is one reason why nanoparticles and thin films have garnered attention. Selection of heterogeneous catalysts in non-bulk form involves immobilizing nanoparticles, thin films, and other specialty structures on electrodes, and thus a second material, the solid support, is added to the electrochemical system.It is well-established that solid support identity can directly impact material or catalytic properties. For example, Rakhi et al. grew Co 3 O 4 nanowires on carbon fiber paper and planar graphitized carbon paper and achieved startlingly different morphologies, 12 while other authors witnessed similar morphological impacts for different systems. 13,14 Superconductivity, 15,16 material hardness, 17 and especially catalytic efficacy in the oxygen reduction reaction [18][19][20][21] have been attributed to solid supports interacting with or changing properties of surface materials that are typically the focus of the study. These works suggest that properties such as catalyst morphology, which is important for CO 2 electrocatalysis, ma...