Integrated Capture and Electroreduction of Flue Gas CO₂ to Formate Using Amine Functionalized SnO_<i>x</i> Nanoparticles

Flue gas from fossil fuel combustion contributes significantly to CO2 emissions. Due to the low CO2 concentration and the existence of reactive O2 in the flue gas, direct flue gas CO2 electrochemical conversion is a challenging task. Here we integrated both CO2 capture and electrochemical conversion into CO2 enriching catalysts by grafting alkanolamines on a tin oxide surface, which can electrochemically reduce simulated flue gas (SFG, 15% CO2, 8% O2, 77% N2) to formate. Maximum formate Faradaic efficiency of 84.2% has been reached by diethanolamine modified tin oxide (DEA–SnOx/C) at −0.75 V vs RHE with partial current density of 6.7 mA·cm–2 in 0.5 M KHCO3 under simulated flue gas atmosphere. Surface amino groups not only enrich CO2 locally but also inhibit O2 reduction, and in situ infrared (in situ IR) spectroscopy confirmed that amino groups accelerate CO2 reduction by promoting the formation of key intermediates (OCHO–*)

Nanostructured Tin Catalysts for Selective Electrochemical Reduction of Carbon Dioxide to Formate

High surface area tin oxide nanocrystals prepared by a facile hydrothermal method are evaluated as electrocatalysts toward CO₂ reduction to formate. At these novel nanostructured tin catalysts, CO₂ reduction occurs selectively to formate at overpotentials as low as ∼340 mV. In aqueous NaHCO₃ solutions, maximum Faradaic efficiencies for formate production of >93% have been reached with high stability and current densities of >10 mA/cm² on graphene supports. The notable reactivity toward CO₂ reduction achieved here may arise from a compromise between the strength of the interaction between CO₂^•– and the nanoscale tin surface and subsequent kinetic activation toward protonation and further reduction

Highly Efficient Alkaline Water Electrolysis Using Alkanolamine-Functionalized Zirconia-Blended Separators

Alkaline water electrolysis is one of the most promising technologies for green hydrogen production. Here, we synthesized a series of alkanolamine-modified zirconia particles by a one-pot method to construct zirconia-based composite membranes for alkaline water electrolysis. Among these membranes, the diethanolamine (DEA)-functionalized zirconia separator exhibits superior hydrophilicity with a low water contact angle of 44° and low area resistance of 0.12 Ω·cm2, which were 47 and 60%, respectively, less than that of the commercial Zirfon PERL UTP 500 separator. Conceivably, the DEA-functionalized zirconia separator presents high electrochemical performance with a current density of 1114 mA cm–2 at 2.0 V with Raney Ni as the cathode catalyst and CoMnO@CoFe layered double hydroxide (LDH) as the anode catalyst at 80 °C, closing the gap with proton exchange membrane electrolysis. In addition, the DEA-modified separator exhibits high stability for over 150 h at a high current density of 500 mA cm–2 and stable cell voltages in 30 wt % KOH at 80 °C

Temperature-Dependent Electrosynthesis of C₂ Oxygenates from Oxalic Acid Using Gallium Tin Oxides

The electrosynthesis of multi-carbon chemicals such as glyoxylic acid (GX) and glycolic acid (GC) from oxalic acid (OA) offers a feasible pathway to achieve sustainable chemical production, especially when coupled with the electroreduction of CO2 to form OA. Here, we demonstrate a series of gallium tin oxide catalysts for selective, controlled OA electroreduction to GX and GC in acidic media. The product distribution can be tuned by changing the reaction temperatures. At room temperature using the GaSnOx/C catalyst, GX can be obtained with a GX Faradaic efficiency (FEGX) of 92.7% at −0.7 V vs RHE and a GX current density (jGX) of −100.2 mA cm–2. At a raised temperature of 80 °C using the GaSnOx/C catalyst, a GC Faradaic efficiency (FEGC) of 91.7% at −0.8 V vs RHE can be obtained. The accelerated OA electroreduction results from the Ga/Sn synergy in the catalysts. A proper Ga/Sn ratio not only enriches OA adsorption and enhances surface binding of intermediates, but also ensures catalyst stability in acidic media

Unexpected C_carbene−X (X: I, Br, Cl) Reductive Elimination from N-Heterocyclic Carbene Copper Halide Complexes Under Oxidative Conditions

The non-spectator roles of NHC ligands have attracted wide attention due to their important implications for reaction mechanisms and subsequent impact on catalyst design. Herein, we report facile Ccarbene−halogen reductive eliminations from NHC copper halide complexes at RT under oxidative conditions. Density functional calculations on a simplified model system suggest that the reactions occur through oxidation of Cu(I) species to Cu(III) species followed by Ccarbene−halogen reductive eliminations from NHC Cu(III) halide complexes. Remarkably short Ccarbene−chloride contacts and rare interactions between the chloride lone pair electrons and the Ccarbene pπ orbital were found for the calculated NHC Cu(III) chlorides. The facile Ccarbene−X reductive elimination reported here warrants consideration as a potential decomposition pathway in reactions involving NHC-supported high-valent metal complexes, especially with late transition metals

Tailored Bimetallic Ni–Sn Catalyst for Electrochemical Ammonia Oxidation to Dinitrogen with High Selectivity

Direct electrochemical ammonia oxidation reaction (eAOR) is an efficient and sustainable strategy to process wastewater containing ammonia, and it endures overoxidation and severely competitive oxygen evolution reaction (OER). Herein, we synthesized a Ni(OH)2/SnO2 composite catalyst by a multistep strategy and applied it to the eAOR process. Ni(OH)2/SnO2 exhibited a N2–N Faradaic efficiency (FEN2–N) of 84.2%, with a N2 partial current density (jN2–N) of 2.7 mA cm–2 at 1.55 V vs reversible hydrogen electrode (RHE) in 0.5 M K2SO4 with 10 mM NH3–N (pH 11). The oxophilic Sn promoted NH3 absorption on Ni sites while suppressing the OER. As the active species, NiOOH accelerated the dimerization of intermediates (*NH2 or *NH) to form N2

Unexpected C_carbene−X (X: I, Br, Cl) Reductive Elimination from N-Heterocyclic Carbene Copper Halide Complexes Under Oxidative Conditions

The non-spectator roles of NHC ligands have attracted wide attention due to their important implications for reaction mechanisms and subsequent impact on catalyst design. Herein, we report facile Ccarbene−halogen reductive eliminations from NHC copper halide complexes at RT under oxidative conditions. Density functional calculations on a simplified model system suggest that the reactions occur through oxidation of Cu(I) species to Cu(III) species followed by Ccarbene−halogen reductive eliminations from NHC Cu(III) halide complexes. Remarkably short Ccarbene−chloride contacts and rare interactions between the chloride lone pair electrons and the Ccarbene pπ orbital were found for the calculated NHC Cu(III) chlorides. The facile Ccarbene−X reductive elimination reported here warrants consideration as a potential decomposition pathway in reactions involving NHC-supported high-valent metal complexes, especially with late transition metals

Electrocatalytic Water Oxidation with a Copper(II) Polypeptide Complex

A self-assembly-formed tri­glycyl­glycine macro­cyclic ligand (TGG^4–) complex of Cu­(II), [(TGG^4–)­Cu^II–OH₂]^2–, efficiently catalyzes water oxidation in a phosphate buffer at pH 11 at room temperature by a well-defined mechanism. In the mechanism, initial oxidation to Cu­(III) is followed by further oxidation to a formal “Cu­(IV)” with formation of a peroxide intermediate, which undergoes further oxidation to release oxygen and close the catalytic cycle. The catalyst exhibits high stability and activity toward water oxidation under these conditions with a high turnover frequency of 33 s^–1

Presentation_1_Boost event-driven tactile learning with location spiking neurons.pdf

Tactile sensing is essential for a variety of daily tasks. Inspired by the event-driven nature and sparse spiking communication of the biological systems, recent advances in event-driven tactile sensors and Spiking Neural Networks (SNNs) spur the research in related fields. However, SNN-enabled event-driven tactile learning is still in its infancy due to the limited representation abilities of existing spiking neurons and high spatio-temporal complexity in the event-driven tactile data. In this paper, to improve the representation capability of existing spiking neurons, we propose a novel neuron model called “location spiking neuron,” which enables us to extract features of event-based data in a novel way. Specifically, based on the classical Time Spike Response Model (TSRM), we develop the Location Spike Response Model (LSRM). In addition, based on the most commonly-used Time Leaky Integrate-and-Fire (TLIF) model, we develop the Location Leaky Integrate-and-Fire (LLIF) model. Moreover, to demonstrate the representation effectiveness of our proposed neurons and capture the complex spatio-temporal dependencies in the event-driven tactile data, we exploit the location spiking neurons to propose two hybrid models for event-driven tactile learning. Specifically, the first hybrid model combines a fully-connected SNN with TSRM neurons and a fully-connected SNN with LSRM neurons. And the second hybrid model fuses the spatial spiking graph neural network with TLIF neurons and the temporal spiking graph neural network with LLIF neurons. Extensive experiments demonstrate the significant improvements of our models over the state-of-the-art methods on event-driven tactile learning, including event-driven tactile object recognition and event-driven slip detection. Moreover, compared to the counterpart artificial neural networks (ANNs), our SNN models are 10× to 100× energy-efficient, which shows the superior energy efficiency of our models and may bring new opportunities to the spike-based learning community and neuromorphic engineering. Finally, we thoroughly examine the advantages and limitations of various spiking neurons and discuss the broad applicability and potential impact of this work on other spike-based learning applications.</p