Cu-catalyzed selective electrocatalytic
upgrading of carbon dioxide/monoxide
to valuable multicarbon oxygenates and hydrocarbons is an attractive
strategy for combating climate change. Despite recent research on
Cu-based catalysts for the CO2 and CO reduction reactions,
surface speciation of the various types of Cu surfaces under reaction
conditions remains a topic of discussion. Herein, in situ surface-enhanced
Raman spectroscopy (SERS) is employed to investigate the speciation
of four commonly used Cu surfaces, i.e., Cu foil, Cu micro/nanoparticles,
electrochemically deposited Cu film, and oxide-derived Cu, at potentials
relevant to the CO reduction reaction in an alkaline electrolyte.
Multiple oxide and hydroxide species exist on all Cu surfaces at negative
potentials, however, the speciation on the Cu foil is distinct from
that on micro/nanostructured Cu. The surface speciation is demonstrated
to correlate with the initial degree of oxidation of the Cu surface
prior to the exposure to negative potentials. Combining reactivity
and spectroscopic results on these four types of Cu surfaces, we conclude
that the oxygen containing surface species identified by Raman spectroscopy
are unlikely to be active in facilitating the formation of C2+ oxygenates in the CO reduction reaction.
Electrochemical deposition is a facile strategy to prepare functional materials but suffers from limitation in thin films and uncontrollable interface engineering. Here we report a universal electrosynthesis of metal hydroxides/oxides on varied substrates via reduction of oxyacid anions. On graphitic substrates, we find that the insertion of nitrate ion in graphene layers significantly enhances the electrodeposit–support interface, resulting in high mass loading and super hydrophilic/aerophobic properties. For the electrocatalytic oxygen evolution reaction, the nanocrystalline cerium dioxide and amorphous nickel hydroxide co-electrodeposited on graphite exhibits low overpotential (177 mV@10 mA cm−2) and sustains long-term durability (over 300 h) at a large current density of 1000 mA cm−2. In situ Raman and operando X-ray diffraction unravel that the integration of cerium promotes the formation of electrocatalytically active gamma-phase nickel oxyhydroxide with exposed (003) facets. Therefore, combining anion intercalation with cathodic electrodeposition allows building robust electrodes with high electrochemical performance.
Intravital microscopy (IVM) emerged and matured as a powerful tool for elucidating pathways in biological processes. Although label-free multiphoton IVM is attractive for its non-perturbative nature, its wide application has been hindered, mostly due to the limited contrast of each imaging modality and the challenge to integrate them. Here we introduce simultaneous label-free autofluorescence-multiharmonic (SLAM) microscopy, a single-excitation source nonlinear imaging platform that uses a custom-designed excitation window at 1110 nm and shaped ultrafast pulses at 10 MHz to enable fast (2-orders-of-magnitude improvement), simultaneous, and efficient acquisition of autofluorescence (FAD and NADH) and second/third harmonic generation from a wide array of cellular and extracellular components (e.g., tumor cells, immune cells, vesicles, and vessels) in living tissue using only 14 mW for extended time-lapse investigations. Our work demonstrates the versatility and efficiency of SLAM microscopy for tracking cellular events in vivo, and is a major enabling advance in label-free IVM.
Highlights d Lactate uptake promotes ATP production to upregulate SREBP1 and SCD1 d Lactate mediates the production of ferroptosis-related lipids in cancer cells d HCAR1/MCT1 inhibition sensitizes cancer cells to ferroptosis induction
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