Strontium-doped perovskite oxides are potential candidates for numerous important catalytic and energy conversion processes, yet strontium segregation to form catalytically and/or electrochemically inert phases results in instability and inefficiency during prolonged operation. In our recent Adv. Mater. paper, we proposed a Sr2+ cation trap by introducing SrMoO4 during cell fabrication, which partially transforms into conductive SrMoO3 under reducing conditions. In the application of solid oxide electrolysis of CO2, a one-order-of-magnitude reduction in degradation rate was achieved compared to the case without cation trapping.  

The vibrational frequency of the surface *CO determines the activity of C2+ product formation from CO2 and CO reduction. Now, published in JACS, we demonstrate this vibrational frequency modulation of surface *CO arising from the identities of the immobilized cations in ionomers, which promotes CO electroreduction to C2+ products. By comparing CO reduction performance and in-situ spectroscopic results on Cu modified with polynorbornene-tethered 3-methyl-imidazolium, 1-methyl-piperidinium, and trimethylammonium cations, we show that the imidazolium cation increases the C2+ partial current densities by a factor of more than 1.5 with a nearly doubled ratio of linearly bound low-frequency *CO vs. linearly bound high-frequency *CO compared to the other two cations, which arises from its more active engagement in charge transfer with CO to weaken the  C≡O bond.

In our recent Nat. Commun.  paper, we showed that polyvinylpyridine, a pyridine-functionalized polymer, preferentially enhances the activity toward multi-carbon products at the CO2-to-CO site by a factor of 3 while reducing that of the CO reduction site. This phenomenon arises from CO2 enrichment, increased hydrophilicity, and the redistribution of Cu surface charge in the presence of polyvinylpyridine. These findings demonstrate the potential to independently control CO2 reduction at different active sites.

Published in Angew. Chem., we show that the behavior of gas bubbles exerts a strong influence on CO2 capture rates and Faradaic efficiencies. We demonstrate that eliminating bubble accumulation by suppressing H2 evolution at the cathode/electrolyte interface facilitates CO2 capture, which ensures the access of CO2 to the alkaline electrode surfaces. We devise a polymer-electrolyte CO2 capture reactor outperforming existing electrochemical DAC devices.

We discovered the correlation between the B-site metals of La0.6Sr0.4Co1-xFexO3-δ and their coke resistance during high-temperature CO2 electrolysis. Elevated Fe/Co ratios enhance the coke resistance by suppressing excessive oxygen vacancy formation and Co/Fe exsolution. This underlying mechanism enables highly stable CO2 electrolysis performance and a tandem reactor for multi-carbon product synthesis with high CO2 utilization efficiency. Details can be found in Adv. Sci..

Congratulations to Huiying, Fan, Jundong, and Quan for winning the special prize in the Challenge Cup competition which was held by Beihang University on Nov 9 this year. The team consists of ten undergraduate and graduate students from Prof. Yanguang Li's group and our group, focusing on catalyst synthesis, membrane fabrication, and device scale-up for CO2 electroreduction.