Title : Atomically dispersed catalysts for energy related catalysis
Abstract:
This presentation includes three works on atomically dispersed catalysts for energy-related catalysts. In the first one, a series of atomically dispersed Co catalysts with different nitrogen coordination numbers are prepared and their CO2 electroreduction catalytic performance is explored. The best catalyst, atomically dispersed Co with two-coordinate nitrogen atoms, achieves both high selectivity and superior activity with 94% CO formation Faradaic efficiency and a current density of 18.1 mA cm-2 at an overpotential of 520 mV. The CO formation turnover frequency reaches a record value of 18,200 h-1, surpassing most reported metal-based catalysts under comparable conditions. Our experimental and theoretical results demonstrate that lower a coordination number facilitates activation of CO2 to the *CO2 - intermediate and hence enhances CO2 electroreduction activity. In the second one, we prepare atomically dispersed Au on carbon nitride (Au1 /C3 N4 ) and investigate its catalytic performance towards N2 electro-reduction to ammonium ions (NH4 +) in sulfuric acid aqueous solution. Au1 /C3 N4 exhibits outstanding NH4 + formation Faradaic efficiency which achieves 11.1% at -0.10 V vs. RHE (reversible hydrogen electrode), outperforming most of the reported catalysts. We then assemble a full electrolytic cell with Au1 /C3 N4 as cathode to reduce N2 into NH4 + and a platinum foil as anode to catalyze hydrogen oxidation reaction. Our experimental results demonstrate that such an electrolytic cell allows us to synthesize NH4 + directly from N2 and H2 with an energy utilization rate of 4.01 mmol kJ-1. In the third work, we investigate the performance of CH4 oxidation on atomically dispersed Ag catalyst. At a temperature of only 323 K, a methanol productivity of 0.44 mmol g-1 h-1 is achieved along with high selectivity, which allows us efficiently convert CH4 into upgraded chemicals. Our works underline the significant role of atomically dispersed catalysts in energy-related catalysis.
