Electrochemical reduction of carbon dioxide (CO) to carbon monoxide (CO) is the first step in the synthesis of more complex carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the reaction suffers from slow kinetics owing to the low local concentration of CO surrounding typical CO reduction reaction catalysts. Alkali metal cations are known to overcome this limitation through non-covalent interactions with adsorbed reagent species, but the effect is restricted by the solubility of relevant salts. Large applied electrode potentials can also enhance CO adsorption, but this comes at the cost of increased hydrogen (H) evolution. Here we report that nanostructured electrodes produce, at low applied overpotentials, local high electric fields that concentrate electrolyte cations, which in turn leads to a high local concentration of CO close to the active CO reduction reaction surface. Simulations reveal tenfold higher electric fields associated with metallic nanometre-sized tips compared to quasi-planar electrode regions, and measurements using gold nanoneedles confirm a field-induced reagent concentration that enables the CO reduction reaction to proceed with a geometric current density for CO of 22 milliamperes per square centimetre at -0.35 volts (overpotential of 0.24 volts). This performance surpasses by an order of magnitude the performance of the best gold nanorods, nanoparticles and oxide-derived noble metal catalysts. Similarly designed palladium nanoneedle electrocatalysts produce formate with a Faradaic efficiency of more than 90 per cent and an unprecedented geometric current density for formate of 10 milliamperes per square centimetre at -0.2 volts, demonstrating the wider applicability of the field-induced reagent concentration concept.

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Fluorescent analogs of adenine that selectively oxidize guanine were used to investigate photoinduced electron transfer through the DNA pi-stack as a function of reactant stacking and energetics. Small variations in these factors led to profound changes in the kinetics and distance dependences of DNA-mediated electron-transfer reactions. Values of beta, a parameter reflecting the dependence of electron transfer on distance, ranged from 0.1 to 1.0 per angstrom. Strong stacking interactions result in the fastest electron-transfer kinetics. Electrons are thus transported preferentially through an intrastrand rather than interstrand pathway. Reactant energetics also modulate the distance dependence of DNA-mediated charge transport. These studies may resolve the range of disparate results previously reported, and paradigms must now be developed to describe these properties of the DNA pi-stack, which can range from insulator- to "wire"-like.

Low-dimensional perovskites have-in view of their high radiative recombination rates-shown great promise in achieving high luminescence brightness and colour saturation. Here we investigate the effect of electron-phonon interactions on the luminescence of single crystals of two-dimensional perovskites, showing that reducing these interactions can lead to bright blue emission in two-dimensional perovskites. Resonance Raman spectra and deformation potential analysis show that strong electron-phonon interactions result in fast non-radiative decay, and that this lowers the photoluminescence quantum yield (PLQY). Neutron scattering, solid-state NMR measurements of spin-lattice relaxation, density functional theory simulations and experimental atomic displacement measurements reveal that molecular motion is slowest, and rigidity greatest, in the brightest emitter. By varying the molecular configuration of the ligands, we show that a PLQY up to 79% and linewidth of 20 nm can be reached by controlling crystal rigidity and electron-phonon interactions. Designing crystal structures with electron-phonon interactions in mind offers a previously underexplored avenue to improve optoelectronic materials' performance.

As energy demand continues to increase, so too do anthropogenic carbon emissions and global temperatures. Renewable energy sources such as solar, wind and hydroelectricity displace fossil fuel carbon emissions and continue to progress to wider deployment. However, long-term (seasonal) energy storage remains a challenge that must be addressed for renewables to meet a major fraction of global energy demand 1 . Carbon dioxide electroreduction to renewable fuels and feedstocks provides an energy storage solution to the seasonal variability of renewable energy sources 2 . When coupled with carbon capture technology, the carbon dioxide reduction reaction (CO 2 RR) offers a means to close the carbon cycle.CO 2 RR electrocatalysts lower energetic barriers to CO 2 reduction by stabilizing intermediates and transition states in the multistep electrochemical reduction process 3 . Copper reduces CO 2 to a wide range of hydrocarbon products such as methane, ethylene, ethanol and propanol 4 . Unfortunately, bulk copper is not selective among various carbon products, and it also suffers Faradaic efficiency (FE) losses to the competing hydrogen evolution reaction.Among possible products, C2+ hydrocarbons are highly sought in view of their commercial value. Ethylene, for example, is a precursor to the production of polyethylene, a major plastic. Selectively producing ethylene over methane circumvents costly paraffin-olefin separation 5 . Developing catalysts that work at ambient conditions to produce C2 selectively over C1 gaseous products will increase the relevance of renewable feedstocks in the chemical sector.Oxide-derived copper is one class of catalyst that has shown enhanced CO 2 RR activity and increased selectivity towards multi-carbon products [6][7][8] . The selectivity of these catalysts is dependent on structural morphology and copper oxidation state 9-17 . Electrochemical reduction of copper oxide catalyst films can lead to grain boundaries, undercoordinated sites and roughened surfaces that are hypothesized to be catalytically active sites 8,18 . Residual oxides, proposed to play a key role in catalysis, may exist after electrochemical reduction 7 . A recent report of oxygen plasma-activated oxide-derived copper catalysts achieved an ethylene FE of 60% at − 0.9 V versus reversible hydrogen electrode (RHE) 9 , with activity attributed to the presence of Cu + species. In situ hard X-ray absorption spectroscopy (hXAS) experiments have suggested stable Cu + species exist at highly negative CO 2 RR potentials of ~− 1.0 versus RHE 9 . However, the presence of Cu + species during CO 2 RR is still the subject of debate; 7,19 and in situ tracking of the copper oxidation state with time resolution during CO 2 RR has remained elusive.Morphological effects of copper nanostructures have a significant effect on the selectivity of CO 2 RR to multi-carbon products [20][21][22][23][24] . Copper catalysts with different morphologies have been synthesized through annealing, chemical treatments on thin films, colloidal synthesis and ...