The electrochemical reduction of CO to multi-carbon products has attracted much attention because it provides an avenue to the synthesis of value-added carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the efficiency of CO conversion to C products remains below that necessary for its implementation at scale. Modifying the local electronic structure of copper with positive valence sites has been predicted to boost conversion to C products. Here, we use boron to tune the ratio of Cu to Cu active sites and improve both stability and C-product generation. Simulations show that the ability to tune the average oxidation state of copper enables control over CO adsorption and dimerization, and makes it possible to implement a preference for the electrosynthesis of C products. We report experimentally a C Faradaic efficiency of 79 ± 2% on boron-doped copper catalysts and further show that boron doping leads to catalysts that are stable for in excess of ~40 hours while electrochemically reducing CO to multi-carbon hydrocarbons.

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Efficient wide-bandgap perovskite solar cells (PSCs) enable high-efficiency tandem photovoltaics when combined with crystalline silicon and other low-bandgap absorbers. However, wide-bandgap PSCs today exhibit performance far inferior to that of sub-1.6-eV bandgap PSCs due to their tendency to form a high density of deep traps. Here, we show that healing the deep traps in wide-bandgap perovskites—in effect, increasing the defect tolerance via cation engineering—enables further performance improvements in PSCs. We achieve a stabilized power conversion efficiency of 20.7% for 1.65-eV bandgap PSCs by incorporating dipolar cations, with a high open-circuit voltage of 1.22 V and a fill factor exceeding 80%. We also obtain a stabilized efficiency of 19.1% for 1.74-eV bandgap PSCs with a high open-circuit voltage of 1.25 V. From density functional theory calculations, we find that the presence and reorientation of the dipolar cation in mixed cation–halide perovskites heals the defects that introduce deep trap states.

This Perspective illustrates how the presence of internal and external electric fields can affect catalytic activity and selectivity, with a focus on heterogeneous catalysts. Specifically, experimental investigations of the electric field influence on catalyst selectivity in pulsed field mass desorption microscopes, scanning tunneling microscopes, probe–bed–probe reactors, continuous-circuit reactors, and capacitor reactors are described. Through these examples, we show how the electric field, whether externally applied or intrinsically present, can affect the behavior of a wide number of materials relevant to catalysis. We review some of the theoretical methods that have been used to elucidate the influence of external electric fields on catalytic reactions, as well as the application of such methods to selective methane activation. In doing so, we illustrate the breadth of possibilities in field-assisted catalysis.

Colloidal nanocrystals combine size-and facet-dependent properties with solution processing. They offer thus a compelling suite of materials for technological

The electrochemical reduction of carbon monoxide is a promising approach for the renewable production of carbon-based fuels and chemicals. Copper shows activity toward multi-carbon products from CO reduction, with reaction selectivity favoring two-carbon products; however, efficient conversion of CO to higher carbon products such as n-propanol, a liquid fuel, has yet to be achieved. We hypothesize that copper adparticles, possessing a high density of under-coordinated atoms, could serve as preferential sites for n-propanol formation. Density functional theory calculations suggest that copper adparticles increase CO binding energy and stabilize two-carbon intermediates, facilitating coupling between adsorbed *CO and two-carbon intermediates to form three-carbon products. We form adparticle-covered catalysts in-situ by mediating catalyst growth with strong CO chemisorption. The new catalysts exhibit an n-propanol Faradaic efficiency of 23% from CO reduction at an n-propanol partial current density of 11 mA cm−2.

This work demonstrates the benefits of applying an external electric field to the methane steam reforming reaction (MSR) in order to tune the catalytic activity of Ni. Through combined DFT calculations and experimental work, we present evidence for the usefulness of an electric field in improving the efficiency of current MSR processesnamely by reducing coke formation and lowering the overall temperature requirements. We focus on the influence of an electric field on (i) the MSR mechanisms, (ii) the rate-limiting step of the most favorable MSR mechanism, (iii) the methanol synthesis reaction during the MSR reaction, and (iv) the formation of coke. Our computational results show that an electric field can change the most favorable MSR mechanism as well as alter the values of the rate constants and equilibrium constants at certain temperatures and, hence, significantly affect the kinetic properties of the overall MSR reaction. Both computational and experimental results also suggest that a positive electric field can impede the formation of coke over a Ni catalytic surface during the MSR reaction. Moreover, the presence of a negative electric field notably increases the rate constant and the equilibrium constant for the methanol synthesis reaction, which suggests a possible direct route from methane to methanol. Finally, a field-induced Brønsted− Evans−Polanyi (BEP) relationship was developed for C−H bond cleavage, C−O bond cleavage, and O−H bond formation over a Ni catalytic surface. Overall, this investigation strengthens our understanding of the effect of an electric field on the Ni-based MSR catalytic system and highlights the benefits of designing heterogeneous reactions under applied electric fields.