Conversion of naturally abundant nitrogen to ammonia is a key (bio)chemical process to sustain life and represents a major challenge in chemistry and biology. Electrochemical reduction is emerging as a sustainable strategy for artificial nitrogen fixation at ambient conditions by tackling the hydrogen- and energy-intensive operations of the Haber–Bosch process. However, it is severely challenged by nitrogen activation and requires efficient catalysts for the nitrogen reduction reaction. Here we report that a boron carbide nanosheet acts as a metal-free catalyst for high-performance electrochemical nitrogen-to-ammonia fixation at ambient conditions. The catalyst can achieve a high ammonia yield of 26.57 μg h–1 mg–1cat. and a fairly high Faradaic efficiency of 15.95% at –0.75 V versus reversible hydrogen electrode, placing it among the most active aqueous-based nitrogen reduction reaction electrocatalysts. Notably, it also shows high electrochemical stability and excellent selectivity. The catalytic mechanism is assessed using density functional theory calculations.

The industrial artificial fixation of atmospheric N2 to NH3 is carried out using the Haber–Bosch process that is not only energy‐intensive but emits large amounts of greenhouse gas. Electrochemical reduction offers an environmentally benign and sustainable alternative for NH3 synthesis. Although Mo‐dependent nitrogenases and molecular complexes effectively catalyze the N2 fixation at ambient conditions, the development of a Mo‐based nanocatalyst for highly performance electrochemical N2 fixation still remains a key challenge. Here, greatly boosted electrocatalytic N2 reduction to NH3 with excellent selectivity by defect‐rich MoS2 nanoflowers is reported. In 0.1 m Na2SO4, this catalyst attains a high Faradic efficiency of 8.34% and a high NH3 yield of 29.28 µg h−1 mg−1cat. at −0.40 V versus reversible hydrogen electrode, much larger than those of defect‐free counterpart (2.18% and 13.41 µg h−1 mg−1cat.), with strong electrochemical stability. Density functional theory calculations show that the potential determining step has a lower energy barrier (0.60 eV) for defect‐rich catalyst than that of defect‐free one (0.68 eV).

Electrohydrogenation of N2 to NH3 is emerging as an environmentally benign strategy to tackle the issues associated with the energy-intensive, CO2-emitting Haber–Bosch process. However, the method is severely challenged by N2 activation and needs efficient N2 reduction reaction (NRR) catalysts. Here, we report that multishelled hollow Cr2O3 microspheres (MHCMs), which are synthesized by a facile synthetic route, can serve as efficient and selective non-noble metal electrocatalysts for NRR. In 0.1 M Na2SO4 solution, the MHCMs achieve a high Faradaic efficiency (6.78%) and a large NH3 yield (25.3 μg h–1 mgcat –1) at −0.9 V vs reversible hydrogen electrode. The MHCMs also exhibit high stability during the reaction. Density functional theory calculations suggest that NRR over MHCMs occurs via both distal associative and partially alternative routes.

CO2 electroreduction reaction offers an attractive approach to global carbon neutrality. Industrial CO2 electrolysis towards formate requires stepped-up current densities, which is limited by the difficulty of precisely reconciling the competing intermediates (COOH* and HCOO*). Herein, nano-crumples induced Sn-Bi bimetallic interface-rich materials are in situ designed by tailored electrodeposition under CO2 electrolysis conditions, significantly expediting formate production. Compared with Sn-Bi bulk alloy and pure Sn, this Sn-Bi interface pattern delivers optimum upshift of Sn p-band center, accordingly the moderate valence electron depletion, which leads to weakened Sn-C hybridization of competing COOH* and suitable Sn-O hybridization of HCOO*. Superior partial current density up to 140 mA/cm2 for formate is achieved. High Faradaic efficiency (>90%) is maintained at a wide potential window with a durability of 160 h. In this work, we elevate the interface design of highly active and stable materials for efficient CO2 electroreduction.

No abstract

Lanthanide coordination polymer nanoparticles (Ln-CPNs) have been recently demonstrated as excellent platforms for biomolecule detection. In this work, we synthesized novel cerium coordination polymer nanoparticles ATP-Ce-Tris CPNs in a simple and quick way using ATP molecules as the biocompatible ligands to Ce(3+) ions in tris(hydroxymethyl)aminomethane hydrochloric (Tris-HCl) solution. In view of the excellent free radical scavenging property of cerium compounds, which is ascribed to the mixed valence state (Ce(3+), Ce(4+)) and the reversible switch from Ce(3+) to Ce(4+), the synthesized ATP-Ce-Tris CPNs was used as artificial peroxidase to selectively and sensitively detect H2O2. The sensing mechanism depends on the oxidation of the fluorescent ATP-Ce(III)-Tris CPNs to nonfluorescent ATP-Ce(IV)-Tris CPNs by H2O2. Compared with those inorganic cerium oxide sensors, this kind of fluoresence ATP-Ce-Tris CPNs sensor needs no additional organic redox dye, such as ABTS (2,20-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), TMB (3,3,5,5-tetramethylbenzidine), or fluorescein as signal molecules. Moreover, such ATP-Ce-Tris CPNs sensor exhibited a more sensitive response to H2O2 with a detection limit down to 0.6 nM, which is 2 orders of magnitude lower than those of cerium oxide sensors. This sensing platform was further extended to the detection of glucose in combination with the specific catalytic effect of glucose oxidase (GOx) for the oxidation of glucose and formation of H2O2.

It is of great importance to design and develop highly active and selective electrocatalysts for the CO reduction reaction (CORR). In this communication, we report an iodide-derived nanostructured silver catalyst (ID-Ag) as an excellent CORR catalyst that is able to electrochemically reduce CO to CO with approximately 94.5% selectivity at the potential of -0.7 V in CO-saturated 0.5 M KHCO. This suggests that the highly electrochemical active surface area and adsorbed I anions onto the surfaces of the electrode contribute to the enhanced activity and selectivity of the nanostructured Ag electrocatalyst toward CO reduction.

In situ-derived boron-doped graphene quantum dots can significantly improve the activity of boron carbide nanosheets for artificial N2 fixation.