Electrochemical reduction of nitrogen to produce ammonia at moderate conditions in aqueous solutions holds great prospect but also faces huge challenges. Considering the high selectivity of Au‐based materials to inhibit competitive hydrogen evolution reaction (HER) and high activity of transition metals such as Fe and Mo toward the nitrogen reduction reaction (NRR), it was proposed that Au‐based alloy materials could act as efficient catalysts for N2 fixation based on density functional theory simulations. Only on Mo3Au(111) surface the adsorption of N2 is stronger than H atom. Thermodynamics combined with kinetics studies were performed to investigate the influence of composition and ratio of Au‐based alloys on NRR and HER. The binding energy and reorganization energy affected performance for the initial N2 activation and hydrogenation process. By considering the free‐energy diagram, the computed potential‐determining step was either the first or the fifth hydrogenation step on metal catalysts. The optimum catalytic activity could be achieved by adjusting atomic proportion in alloys to make all intermediate species exhibit moderate adsorption. Free‐energy diagrams of N2 hydrogenation via Langmuir‐Hinshelwood mechanism and hydrogen evolution via Tafel mechanism were compared to reveal that the Mo3Au surface showed satisfactory catalytic performance by simultaneously promoting NRR and suppressing HER. Theoretical simulations demonstrated that Au‐Mo alloy materials could be applied as high‐performance electrocatalysts for NRR.

CO 2 can be electrochemically reduced to different products depending on the nature of catalysts. In this work, we report comprehensive kinetic studies on catalytic selectivity and product distribution of the CO 2 reduction reaction on various metal surfaces. The influences on reaction kinetics can be clearly analyzed from the variation of reaction driving force (binding energy difference) and reaction resistance (reorganization energy). Moreover, the CO 2 RR product distributions are further affected by external factors such as electrode potential and solution pH. A potential-mediated mechanism is found to determine the competing two-electron reduction products of CO 2 that shifts from thermodynamics-controlled product formic acid at less negative electrode potentials to kinetic-controlled product CO at more negative electrode potentials. Based on detailed kinetic simulations, a three-parameter descriptor is applied to identify the catalytic selectivity of CO, formate, hydrocarbons/alcohols, as well as side product H 2 . The present kinetic study not only well explains the catalytic selectivity and product distribution of experimental results but also provides a fast way for catalyst screening.

Electrocatalytic CO2 reduction reaction (CO2RR) based on molecular catalysts, for example, cobalt porphyrin, is promising to enhance the carbon cycle and mitigate current climate crisis. However, the electrocatalytic performance and accurate evaluations remain problems because of either the low loading amount or the low utilization rate of the electroactive CoN4 sites. Herein a monomer is synthesized, cobalt(II)‐5,10,15,20‐tetrakis(3,5‐di(thiophen‐2‐yl)phenyl)porphyrin (CoP), electropolymerized onto carbon nanotubes (CNTs) networks, affording a molecular electrocatalyst of 3D microporous nanofilm (EP‐CoP, 2–3 nm thickness) with highly dispersed CoN4 sites. The new electrocatalyst shortens the electron transfer pathway, accelerates the redox kinetics of CoN4 sites, and improves the durability of the electrocatalytic CO2RR. From the intrinsic redox behavior of CoN4 sites, the effective utilization rate is obtained as 13.1%, much higher than that of the monomer assembled electrode (5.8%), and the durability is also promoted dramatically (>40 h) in H‐type cells. In commercial flow cells, EP‐CoP can achieve a faradic efficiency for CO (FECO) over 92% at an overpotential of 160 mV. At a higher overpotential of 620 mV, the working current density can reach 310 mA cm−2 with a high FECO of 98.6%, representing the best performance for electrodeposited molecular porphyrin electrocatalysts.

Organic carbonyl compounds are regarded as promising candidates for next-generation rechargeable batteries in terms of low cost, environmental protection, and high capacity. The carbonyl utilization is a key issue to...

Dedicated to the 60th Birthday of Professor Licheng SunThe synthesis of Co-doped Mn 3 O 4 nanocubes was achieved via galvanic replacement reactions for photo-reduction of CO 2 . Co@Mn 3 O 4 nanocubes could efficiently photo-reduce CO 2 to CO with a remarkable turnover number of 581.8 using [Ru-(bpy) 3 ]Cl 2 • 6H 2 O as photosensitizer and triethanolamine as sacrificial agent in acetonitrile and water. The galvanic replaced Co species are homogeneously distributed at the outer surface of Mn 3 O 4 , providing catalytic active sites during CO 2 reduction reactions, which facilitate the separation and migration of photogenerated charge carriers, further benefiting the outstanding photocatalytic performance of CO 2 reduction. Density functional theory calculations revealed that the decreasing of conduction band maximum in Co@Mn 3 O 4 was beneficial to the electron attachment from the excited sensitized molecule, which promoted photocatalytic reduction of CO 2 .