Electrochemical conversion of nitrate (NO 3 − ) into ammonia (NH 3 ) recycles nitrogen and offers a route to the production of NH 3 , which is more valuable than dinitrogen gas. However, today's development of NO 3 − electroreduction remains hindered by the lack of a mechanistic picture of how catalyst structure may be tuned to enhance catalytic activity. Here we demonstrate enhanced NO 3 − reduction reaction (NO 3 − RR) performance on Cu 50 Ni 50 alloy catalysts, including a 0.12 V upshift in the half-wave potential and a 6-fold increase in activity compared to those obtained with pure Cu at 0 V vs reversible hydrogen electrode (RHE). Ni alloying enables tuning of the Cu d-band center and modulates the adsorption energies of intermediates such as *NO 3 − , *NO 2 , and *NH 2 . Using density functional theory calculations, we identify a NO 3 − RR-to-NH 3 pathway and offer an adsorption energy−activity relationship for the CuNi alloy system. This correlation between catalyst electronic structure and NO 3 − RR activity offers a design platform for further development of NO 3 − RR catalysts.

With high scalability and independent control over energy and power, redox flow batteries (RFBs) stand out as an important large-scale energy storage system. However, the widespread application of conventional RFBs is limited by the uncompetitive performance, as well as the high cost and environmental concerns associated with the use of metal-based redox species. In consideration of advantageous features such as potentially low cost, vast molecular diversity, and highly tailorable properties, organic and organometallic molecules emerge as promising alternative electroactive species for building sustainable RFBs. This review presents a systematic molecular engineering scheme for designing these novel redox species. We provide detailed synthetic strategies for modifying the organic and organometallic redox species in terms of solubility, redox potential, and molecular size. Recent advances are then introduced covering the reaction mechanisms, specific functionalization methods, and electrochemical performances of redox species classified by their molecular structures. Finally, we conclude with an analysis of the current challenges and perspectives on future directions in this emerging research field.

Conductive polymers combine the attractive properties associated with conventional polymers and unique electronic properties of metals or semiconductors. Recently, nanostructured conductive polymers have aroused considerable research interest owing to their unique properties over their bulk counterparts, such as large surface areas and shortened pathways for charge/mass transport, which make them promising candidates for broad applications in energy conversion and storage, sensors, actuators, and biomedical devices. Numerous synthetic strategies have been developed to obtain various conductive polymer nanostructures, and high-performance devices based on these nanostructured conductive polymers have been realized. This Tutorial review describes the synthesis and characteristics of different conductive polymer nanostructures; presents the representative applications of nanostructured conductive polymers as active electrode materials for electrochemical capacitors and lithium-ion batteries and new perspectives of functional materials for next-generation high-energy batteries, meanwhile discusses the general design rules, advantages, and limitations of nanostructured conductive polymers in the energy storage field; and provides new insights into future directions. Key learning points(1) General synthetic approaches and fundamental properties of 1D, 2D, and 3D nanostructured conductive polymers.

Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions provides an intriguing picture for the conversion of N into NH . However, electrocatalytic NRR mainly relies on metal-based catalysts, and it remains a grand challenge in enabling effective N activation on metal-free catalysts. Here we report a defect engineering strategy to realize effective NRR performance (NH yield: 8.09 μg h mg , Faradaic efficiency: 11.59 %) on metal-free polymeric carbon nitride (PCN) catalyst. Illustrated by density functional theory calculations, dinitrogen molecule can be chemisorbed on as-engineered nitrogen vacancies of PCN through constructing a dinuclear end-on bound structure for spatial electron transfer. Furthermore, the N-N bond length of adsorbed N increases dramatically, which corresponds to "strong activation" system to reduce N into NH . This work also highlights the significance of defect engineering for improving electrocatalysts with weak N adsorption and activation ability.

N fixation by the electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is regarded as a potential approach to achieve NH production, which still heavily relies on the Haber-Bosch process at the cost of huge energy and massive production of CO . A noble-metal-free Bi V O /CeO hybrid with an amorphous phase (BVC-A) is used as the cathode for electrocatalytic NRR. The amorphous Bi V O contains significant defects, which play a role as active sites. The CeO not only serves as a trigger to induce the amorphous structure, but also establishes band alignment with Bi V O for rapid interfacial charge transfer. Remarkably, BVC-A shows outstanding electrocatalytic NRR performance with high average yield (NH : 23.21 μg h mg , Faradaic efficiency: 10.16 %) under ambient conditions, which is superior to the Bi V O /CeO hybrid with crystalline phase (BVC-C) counterpart.

We report large-scale synthesis of silica nanowires (SiONWs) using an excimer laser ablation method. Silica was produced in the form of amorphous nanowires at a diameter of ∼15 nm and a length up to hundreds micrometers. The SiONWs emit stable and high brightness blue light at energies of 2.65 and 3.0 eV. The intensity of the emission is two orders of magnitude higher than that of porous silicon. The SiONWs may have potential applications in high-resolution optical heads of scanning near-field optical microscope or nanointerconnections in future integrated optical devices.

Electrical energy storage system such as secondary batteries is the principle power source for portable electronics, electric vehicles and stationary energy storage. As an emerging battery technology, Li-redox flow batteries inherit the advantageous features of modular design of conventional redox flow batteries and high voltage and energy efficiency of Li-ion batteries, showing great promise as efficient electrical energy storage system in transportation, commercial, and residential applications. The chemistry of lithium redox flow batteries with aqueous or non-aqueous electrolyte enables widened electrochemical potential window thus may provide much greater energy density and efficiency than conventional redox flow batteries based on proton chemistry. This Review summarizes the design rationale, fundamentals and characterization of Li-redox flow batteries from a chemistry and material perspective, with particular emphasis on the new chemistries and materials. The latest advances and associated challenges/ opportunities are comprehensively discussed.

Li2S is one of the most promising cathode materials for Li‐ion batteries because of its high theoretical capacity and compatibility with Li‐metal‐free anode materials. However, the poor conductivity and electrochemical reactivity lead to low initial capacity and severe capacity decay. In this communication, a nitrogen and phosphorus codoped carbon (N,P–C) framework derived from phytic acid doped polyaniline hydrogel is designed to support Li2S nanoparticles as a binder‐free cathode for Li–S battery. The porous 3D architecture of N and P codoped carbon provides continuous electron pathways and hierarchically porous channels for Li ion transport. Phosphorus doping can also suppress the shuttle effect through strong interaction between sulfur and the carbon framework, resulting in high Coulombic efficiency. Meanwhile, P doping in the carbon framework plays an important role in improving the reaction kinetics, as it may help catalyze the redox reactions of sulfur species to reduce electrochemical polarization, and enhance the ionic conductivity of Li2S. As a result, the Li2S/N,P–C composite electrode delivers a stable capacity of 700 mA h g−1 with average Coulombic efficiency of 99.4% over 100 cycles at 0.1C and an areal capacity as high as 2 mA h cm−2 at 0.5C.