Search

Aqueous zinc-ion battery is regarded as one of the promising devices for large-scale energy storage systems owing to its high safety, cost-effectiveness, and competitive electrochemical properties. However, the dendrite growth on zinc metal anodes dramatically hinders its further practical applications, and the internal mechanism of dendrite evolution is still unclear. The introduction of a protective layer on the anode interface is an effective method to avoid zinc dendrite growth. Herein, a two-dimensional (2D) atomic surface diffusion mechanism is proposed to reveal the evolution of zinc deposition from tiny protrusion to dendrite under uneven electric and ionic fields. Further, the conductive copper nitride (CN) protective layer is constructed on the zinc metal anode by a facile and scalable magnetron sputtering approach. Their protective layer possesses a high zinc affinity and high diffusion barrier for zinc atom migration, leading to spacious nucleation, and uniform zinc deposition, thus significantly boosting the electrochemical stability. For the first time, the role of the restricted 2D atomic surface diffusion mechanism in inhibiting the formation of zinc tiny protrusion that induces uneven electric and ionic fields is revealed. This work can provide a novel insight for future research on dendrite-free zinc metal anodes by interfacial modification., (© 2021 Wiley-VCH GmbH.)

Cu‐based catalysts have been identified as the most promising candidates for generation of C2+ products in electrochemical CO2 reduction reaction. Defect engineering in catalysts is a widely employed strategy for promoting C−C coupling on Cu. However, comprehensive understanding of defect structure‐to‐activity relationship has not been obtained. In this study, controllable defects generation is achieved, which leads to a series of Cu‐based catalysts with various phase mixing degrees. It is observed that the Faradaic efficiency toward C2+ products increases with the phase mixing degree, reaching 81 % at maximum. In situ infrared absorption spectroscopy reveals that the catalysts with higher phase mixing degree tend to form *CO more easily and possess higher retention of *CO under high overpotential window, thereby promoting C−C coupling. This work sheds new light on the relationship between defects and C−C coupling, and the rational developed of more advanced Cu‐base catalysts. [ABSTRACT FROM AUTHOR]

Catalysts involving post‐transition metals have shown almost invincible performance on generating formate in electrochemical CO2 reduction reaction (CO2RR). Conversely, Cu without post‐transition metals has struggled to achieve comparable activity. In this study, a sulfur (S)‐doped‐copper (Cu)‐based catalyst is developed, exhibiting excellent performance in formate generation with a maximum Faradaic efficiency of 92 % and a partial current density of 321 mA cm−2. Ex situ structural elucidations reveal the presence of abundant grain boundaries and high retention of S−S bonds from the covellite phase during CO2RR. Furthermore, thermodynamic calculations demonstrate that S−S bonds can moderate the binding energies with various intermediates, further improving the activity of the formate pathway. This work is significant in modifying a low‐cost catalyst (Cu) with a non‐metallic element (S) to achieve comparable performance to mainstream catalysts for formate generation in industrial grade. [ABSTRACT FROM AUTHOR]

The conventional industrial production of nitrogen‐containing fertilizers, such as urea and ammonia, relies heavily on energy‐intensive processes, accounting for approximately 3 % of global annual CO2 emissions. Herein, we report a sustainable electrocatalytic approach that realizes direct and selective synthesis of urea and ammonia from co‐reduction of CO2 and nitrates under ambient conditions. With the assistance of a copper (Cu)‐based salphen organic catalyst, outstanding urea (3.64 mg h−1 mgcat−1) and ammonia (9.73 mg h−1 mgcat−1) yield rates are achieved, in addition to a remarkable Faradaic efficiency of 57.9±3 % for the former. This work proposes an appealing sustainable route to converting greenhouse gas and waste nitrates by renewable energies into value‐added fertilizers. [ABSTRACT FROM AUTHOR]

We demonstrate the synthesis of a core-shell catalyst consisting of a Pt monolayer as the shell arid porous/hollow Pd-Cu alloy nanoparticles as the core. The porous/hollow Pd-Cu nanoparticles were fabricated by selectively dissolving a less noble metal, Cu, using an electrochemical dealloying process. The Pt mass activity for the oxygen reduction reaction of a Pt monolayer deposited on such a porous core is 3.5 times higher than that of a Pt monolayer deposited on bulk Pd nanoparticles and 1 4times higherthan that of state-of-the-art Pt/C electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hybrid DFT model is developed to simulate the water/Cu interface. • Effects of crystal facet and pH on nitrate reduction mechanism over Cu are studied. • In acidic media, nitrate is reduced to NH 3 on both Cu(1 0 0) and Cu(1 1 1). • In alkaline media, NH 2 OH forms on Cu(1 0 0) at low overpotentials, and NH 3 is kinetically favorable on Cu(1 1 1). As a beneficial technology for nitrate removal and ammonia synthesis, electrocatalytic nitrate reduction reaction (NO 3 RR) has received much attention in experimental and theoretical studies. Previous work suggests that Cu is one of the most active electrocatalysts for NO 3 RR. However, the fundamental reaction mechanism, governing the activity and selectivity of Cu towards NO 3 RR with various facets and pH, remains elusive. Herein, a hybrid model is developed by combining the explicit water layer and the implicit solvation scheme to simulate the water/Cu interface based on theoretical density functional theory simulations. The hybrid model is used to elucidate the effects of crystal facets and pH on NO 3 RR mechanism over Cu. Our simulation results illustrate that NO 3 RR in acidic media proceeds via the formation of *NOH to produce NH 3 on both (1 0 0) and (1 1 1) facets. While in alkaline media, Cu(1 0 0) prefers the formation of NH 2 OH via *NHO at low overpotentials, and Cu(1 1 1) kinetically favors the formation of NH 3. In general, the (1 0 0) facet is more active towards NO 3 RR than the (1 1 1) facet, especially at higher pH, due to lower thermodynamic and kinetic barriers. Our results provide deeper mechanistic insights into the effects of both crystal facets and pH on the electrocatalytic activity and product selectivity of Cu towards NO 3 RR. The hybrid model developed here can be applied to other electrochemical reactions at water/metal interfaces. [ABSTRACT FROM AUTHOR]