This review underlines the strategies to suppress HER for selective NRR in view of proton-/electron-transfer kinetics, thermodynamics, and electrocatalyst design on the basis of deep understanding for NRR mechanisms.

This review underlines innovative design strategies for CO2RR system, also distinctively presents the current status and new trend.

Electrochemical reduction of carbon dioxide to hydrocarbons, driven by renewable power sources, is a fascinating and clean way to remedy greenhouse gas emission as a result of overdependence on fossil fuels and produce value-added fine chemicals. The Cu-based catalysts feature unique superiorities; nevertheless, achieving high hydrocarbon selectivity is still inhibited and remains a great challenge. In this study, we report on a tailor-made multifunction-coupled Cu-metal–organic framework (Cu-MOF) electrocatalyst by time-resolved controllable restructuration from Cu2O to Cu2O@Cu-MOF. The restructured electrocatalyst features a time-responsive behavior and is equipped with high specific surface area for strong adsorption capacity of CO2 and abundant active sites for high electrocatalysis activity based on the as-produced MOF on the surface of Cu2O, as well as the accelerated charge transfer derived from the Cu2O core in comparison with the Cu-MOF. These intriguing characteristics finally lead to a prominent performance towards hydrocarbons, with a high hydrocarbon Faradaic efficiency (FE) of 79.4%, particularly, the CH4 FE as high as 63.2% (at −1.71 V). This work presents a novel and efficient strategy to configure MOF-based materials in energy and catalysis fields, with a focus on big surface area, high adsorption ability, and much more exposed active sites.

The sluggish electrochemical kinetics of sulfur species has impeded the wide adoption of lithium-sulfur battery, which is one of the most promising candidates for next-generation energy storage system. Here, we present the electronic and geometric structures of all possible sulfur species and construct an electronic energy diagram to unveil their reaction pathways in batteries, as well as the molecular origin of their sluggish kinetics. By decoupling the contradictory requirements of accelerating charging and discharging processes, we select two pseudocapacitive oxides as electron-ion source and drain to enable the efficient transport of electron/Li+ to and from sulfur intermediates respectively. After incorporating dual oxides, the electrochemical kinetics of sulfur cathode is significantly accelerated. This strategy, which couples a fast-electrochemical reaction with a spontaneous chemical reaction to bypass a slow-electrochemical reaction pathway, offers a solution to accelerate an electrochemical reaction, providing new perspectives for the development of high-energy battery systems.

The application of graphene for electrochemical energy storage has received tremendous attention; however, challenges remain in synthesis and other aspects. Here we report the synthesis of high-quality, nitrogen-doped, mesoporous graphene particles through chemical vapor deposition with magnesium-oxide particles as the catalyst and template. Such particles possess excellent structural and electrochemical stability, electronic and ionic conductivity, enabling their use as high-performance anodes with high reversible capacity, outstanding rate performance (e.g., 1,138 mA h g −1 at 0.2 C or 440 mA h g −1 at 60 C with a mass loading of 1 mg cm −2 ), and excellent cycling stability (e.g., >99% capacity retention for 500 cycles at 2 C with a mass loading of 1 mg cm −2 ). Interestingly, thick electrodes could be fabricated with high areal capacity and current density (e.g., 6.1 mA h cm −2 at 0.9 mA cm −2 ), providing an intriguing class of materials for lithium-ion batteries with high energy and power performance.

Limited by the size of microelectronics, as well as the space of electrical vehicles, there are tremendous demands for lithium-ion batteries with high volumetric energy densities. Current lithium-ion batteries, however, adopt graphite-based anodes with low tap density and gravimetric capacity, resulting in poor volumetric performance metric. Here, by encapsulating nanoparticles of metallic tin in mechanically robust graphene tubes, we show tin anodes with high volumetric and gravimetric capacities, high rate performance, and long cycling life. Pairing with a commercial cathode material LiNi0.6Mn0.2Co0.2O2, full cells exhibit a gravimetric and volumetric energy density of 590 W h Kg−1 and 1,252 W h L−1, respectively, the latter of which doubles that of the cell based on graphite anodes. This work provides an effective route towards lithium-ion batteries with high energy density for a broad range of applications.

Integrated/cascade plasma-enabled N2 oxidation and electrocatalytic NO x – (where x = 2, 3) reduction reaction (pNOR-eNO x –RR) holds great promise for the renewable synthesis of ammonia (NH3). However, the corresponding activated effects and process of plasma toward N2 and O2 molecules and the mechanism of eNO x –RR to NH3 are unclear and need to be further uncovered, which largely limits the large-scale deployment of this process integration technology. Herein, we systematically investigate the plasma-enabled activation and recombination processes of N2 and O2 molecules, and more meaningfully, the mechanism of eNO x –RR at a microscopic level is also decoupled using copper (Cu) nanoparticles as a representative electrocatalyst. The concentration of produced NO x in the pNOR system is confirmed as a function of the length for spark discharge as well as the volumetric ratio for N2 and O2 feeding gas. The successive protonation process of NO x – and the key N-containing intermediates (e.g., −NH2) of eNO x –RR are detected with in situ infrared spectroscopy. Besides, in situ Raman spectroscopy further reveals the dynamic reconstruction process of Cu nanoparticles during the eNO x –RR process. The Cu nanoparticle-driven pNOR-eNO x –RR system can finally achieve a high NH3 yield rate of ∼40 nmol s–1 cm–2 and Faradaic efficiency of nearly 90%, overperforming the benchmarks reported in the literature. It is anticipated that this work will stimulate the practical development of the pNOR-eNO x –RR system for the green electrosynthesis of NH3 directly from air and water under ambient conditions.

The modification of the material surface by the second-phase particles enables the electron interaction on the Fermi level or the energy band between different materials, which can achieve the improvement of gas-sensing properties. Herein, a novel composite of PbS quantum-dots-modified MoS 2 (MoS 2 / PbS) is synthesized by combination of hydrothermal method with chemical precipitation and fabricated into the gas sensor to investigate its enhanced gas-sensing properties caused by the modification of PbS quantum dots at room temperature. It is found that the responsivity of MoS 2 /PbS is obviously higher than that of pure MoS 2 gas sensor throughout the whole test range, and MoS 2 /PbS gas sensor has better selectivity compared with pure MoS 2 gas sensor at room temperature. The response of MoS 2 / PbS gas sensor is about 50 times higher than that of MoS 2 gas sensor at 100 ppm NO 2 concentration. The recovery behavior is greatly improved, and the resistance of MoS 2 /PbS gas sensor can return completely with almost no drift (the recovery ratio is more than 99%). The enhanced gas-sensing properties of MoS 2 /PbS, which are superior to those of pure MoS 2 , are ascribed to the large surface area of MoS 2 combined with the high responsivity of PbS quantum dots for NO 2 . The formation of heterojunctions leads to the competitive adsorption of the target gases, which can prevent MoS 2 from being oxidized, further improving the stability of gas sensor. Furthermore, to profoundly discuss the enhanced performances and the sensing mechanism, the molecular models of adsorption systems are constructed to calculate the adsorption energies and the diffusion characters of NO 2 via density functional theory. We expect that our work can offer a useful guideline for enhancing the gassensing properties at room temperature.