Boron-doped graphene with different boron structures was rationally synthesized to enhance the adsorption of N 2 , thus enabling an efficient metal-free electrocatalyst for electrochemical N 2 reduction in aqueous solution at ambient conditions. At a doping level of 6.2%, boron-doped graphene achieved a NH 3 production rate of 9.8 mg$hr À1 $cm À2 and an excellent faradic efficiency (10.8% at À0.5 V versus reversible hydrogen electrode).

The electrocatalytic reduction of CO2 into value-added chemicals such as hydrocarbons has the potential for supplying fuel energy and reducing environmental hazards, while the accurate tuning of electrocatalysts at the ultimate single-atomic level remains extremely challenging. In this work, we demonstrate an atomic design of multiple oxygen vacancy-bound, single-atomic Cu-substituted CeO2 to optimize the CO2 electrocatalytic reduction to CH4. We carried out theoretical calculations to predict that the single-atomic Cu substitution in CeO2(110) surface can stably enrich up to three oxygen vacancies around each Cu site, yielding a highly effective catalytic center for CO2 adsorption and activation. This theoretical prediction is consistent with our controlled synthesis of the Cu-doped, mesoporous CeO2 nanorods. Structural characterizations indicate that the low concentration (<5%) Cu species in CeO2 nanorods are highly dispersed at single-atomic level with an unconventionally low coordination number ∼5, suggesting the direct association of 3 oxygen vacancies with each Cu ion on surfaces. This multiple oxygen vacancy-bound, single atomic Cu-substituted CeO2 enables an excellent electrocatalytic selectivity in reducing CO2 to methane with a faradaic efficiency as high as 58%, suggesting strong capabilities of rational design of electrocatalyst active centers for boosting activity and selectivity.

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The continuous increase of CO2 concentration in the atmosphere has been imposing an imminent threat for global climate change and environmental hazards. In recent years, the electrochemical or photochemical conversion of CO2 into value‐added chemicals or fuels has received significant attention, as it may enable an attractive means to mitigate the atmospheric CO2 concentration and complete the imbalanced carbon‐neutral energy cycle, as well as create renewable energy resources for human use. Among the different electrocatalysts being studied, Cu‐based materials have been demonstrated as the only category of candidates that allows the conversion of CO2 into a variety of reducing products, including carbon monoxide, hydrocarbons, and alcohols. Herein, the reaction pathways for different Cu‐based catalysts for C1 and C2+ products are introduced. Then, different parameters in tuning Cu‐based electrocatalysts are summarized and discussed, including the morphologies, compositions, crystal facets, and oxide derivation. In addition, various types of parameters for CO2 electroreduction are also described, particularly the option of electrolytes such as aqueous, ionic liquids, and organic solutions. Finally, the current challenges are discussed and the potential strategies to facilitate the future development of CO2 electroreduction are summarized.

Electrochemical reduction of carbon dioxide (CO2) is a promising approach to solve both renewable energy storage and carbon‐neutral energy cycles, while the capability of selective reduction to C2+ products has still been quite limited. In this work, partially reduced copper oxide nanodendrites with rich surface oxygen vacancies (CuOx–Vo) are developed, serving as excellent Lewis base sites for enhanced CO2 adsorption and subsequent electrochemical reduction. Theoretical calculations reveal that these oxygen vacancy‐rich CuOx surfaces provide strong binding affinities to the intermediates of *CO and *COH, but weak affinity to *CH2, thus leading to efficient formation of C2H4. As a result, the partially reduced CuOx nanodendrites exhibit one of the highest C2H4 production Faradaic efficiencies of 63%. The electrochemical stability test further shows that the C2H4 Faradaic efficiency strongly depends on the oxygen vacancy density in CuOx, which can further be regenerated for several cycles, thus suggesting the critical role of oxygen vacancies for the C2 product selectivity.

In this study, a hierarchical ZnCo2O4@MnO2 core–shell nanotube arrays electrode was developed by a facile two-step method.

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The rational design of active and durable reversible oxygen electrocatalysts plays a key role in renewable energy conversion and storage. Here we developed copper and cobalt-based oxide/iron hydroxide hybrid nanowire arrays (CuCoO x /FeOOH) via a three-step growth−annealing−conversion approach. These hybrid nanowires offer a large surface area for electrocatalytic sites, abundant pores for fast electrolyte access, efficient charge transfer, and strong coupling between CuCoO x and FeOOH components. Attributed to these features, the CuCoO x /FeOOH nanowires exhibit excellent bifunctional oxygen evolution reaction and oxygen reduction reaction activities, including low overpotentials, high current densities, and outstanding stabilities. Using the CuCoO x /FeOOH electrocatalyst as the oxygen electrode, a rechargeable zinc−air battery was fabricated to exhibit a small charge−discharge overpotential (0.75 V at 10 mA•cm −2 ) and a long-term cycling stability (150 cycles), thus suggesting new bifunctional electrocatalysts for energy conversion and storage applications.